README.md

# [LeetCode](https://leetcode.com/problemset/all/)

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* R.I.P. to my old Leetcode repository, where there were `5.7k+` stars and `2.2k+` forks (ever the top 3 in the field).
* Since free questions may be even mistakenly taken down by some companies, only solutions will be post on now.
* There are new LeetCode questions every week. I'll keep updating for full summary and better solutions.
* For more problem solutions, you can see my [LintCode](https://github.com/kamyu104/LintCode), [GoogleKickStart](https://github.com/kamyu104/GoogleKickStart-2021) repositories.
* For more challenging problem solutions, you can also see my [GoogleCodeJam](https://github.com/kamyu104/GoogleCodeJam-2021), [FacebookHackerCup](https://github.com/kamyu104/FacebookHackerCup-2021) repositories.
* Hope you enjoy the journey of learning data structures and algorithms.
* Notes: "🔒" means your subscription of [LeetCode premium membership](https://leetcode.com/subscribe/) is required for reading the question.

## Solutions
- [0001 - 1000](./0001-1000.md)

## Algorithms

* [Bit Manipulation](https://github.com/kamyu104/LeetCode-Solutions#bit-manipulation)
* [Array](https://github.com/kamyu104/LeetCode-Solutions#array)
* [String](https://github.com/kamyu104/LeetCode-Solutions#string)
* [Linked List](https://github.com/kamyu104/LeetCode-Solutions#linked-list)
* [Stack](https://github.com/kamyu104/LeetCode-Solutions#stack)
* [Queue](https://github.com/kamyu104/LeetCode-Solutions#queue)
* [Binary Heap](https://github.com/kamyu104/LeetCode-Solutions#binary-heap)
* [Tree](https://github.com/kamyu104/LeetCode-Solutions#tree)
* [Hash Table](https://github.com/kamyu104/LeetCode-Solutions#hash-table)
* [Math](https://github.com/kamyu104/LeetCode-Solutions#math)
* [Sort](https://github.com/kamyu104/LeetCode-Solutions#sort)
* [Two Pointers](https://github.com/kamyu104/LeetCode-Solutions#two-pointers)
* [Recursion](https://github.com/kamyu104/LeetCode-Solutions#recursion)
* [Binary Search](https://github.com/kamyu104/LeetCode-Solutions#binary-search)
* [Binary Search Tree](https://github.com/kamyu104/LeetCode-Solutions#binary-search-tree)
* [Breadth-First Search](https://github.com/kamyu104/LeetCode-Solutions#breadth-first-search)
* [Depth-First Search](https://github.com/kamyu104/LeetCode-Solutions#depth-first-search)
* [Backtracking](https://github.com/kamyu104/LeetCode-Solutions#backtracking)
* [Dynamic Programming](https://github.com/kamyu104/LeetCode-Solutions#dynamic-programming)
* [Greedy](https://github.com/kamyu104/LeetCode-Solutions#greedy)
* [Graph](https://github.com/kamyu104/LeetCode-Solutions#graph)
* [Geometry](https://github.com/kamyu104/LeetCode-Solutions#geometry)
* [Simulation](https://github.com/kamyu104/LeetCode-Solutions#simulation)
* [Design](https://github.com/kamyu104/LeetCode-Solutions#design)
* [Concurrency](https://github.com/kamyu104/LeetCode-Solutions#concurrency)

## Database

* [SQL](https://github.com/kamyu104/LeetCode-Solutions#sql)


## Shell

* [Shell Script](https://github.com/kamyu104/LeetCode-Solutions#shell-script)

## Reference

* C++
    * [STL Time Complexity (Detailed)](http://www.cplusplus.com/reference/stl/)
    * [STL Time Complexity (Summary)](http://john-ahlgren.blogspot.com/2013/10/stl-container-performance.html)
    * [Data Structure and Algorithms Cheat Sheet](https://github.com/gibsjose/cpp-cheat-sheet/blob/master/Data%20Structures%20and%20Algorithms.md)
* Python
    * [Time Complexity](https://wiki.python.org/moin/TimeComplexity)
* Algorithms
    * [Rosetta Code](https://rosettacode.org)
    * [CP-Algorithms](https://cp-algorithms.com)
    * [KACTL](https://github.com/kth-competitive-programming/kactl)
    * [Codeforces](https://codeforces.com/)
* Math
    * [Stack Exchange](https://math.stackexchange.com)     
* Visualization
    * [VisuAlgo](https://visualgo.net/en)
    * [Data Structure Visualizations](https://www.cs.usfca.edu/~galles/visualization/Algorithms.html)
    * [Algorithm Visualizer](https://algorithm-visualizer.org/)
 * Handy Table
    * [Thinking Techniques](https://sites.google.com/site/mostafasibrahim/programming-competitions/thinking-techniques) as follows:

| n | Complexity | Possible Algorithms & Techniques |
| - | - | - |
| 10<sup>18</sup>+ | _O(1)_ | Math |
| 10<sup>18</sup> | _O(logn)_ | Binary & Ternary Search / Matrix Power / Cycle Tricks / Big Simulation Steps / Values Reranking / Math |
| 10<sup>16</sup> | _O(n<sup>1/2</sup>)_ | Math |
| 10<sup>8</sup> | _O(n)_ | Greedy / Ad-hoc / DP |
| 4×10<sup>7</sup> | _O(nlogn)_ | Linear # Calls to Binary & Ternary Search / Pre-processing & Querying / Divide and Conquer |
| 10<sup>4</sup> | _O(n<sup>2</sup>)_ | Ad-hoc / DP / Greedy / Divide and Conquer / Branch and Bound |
| 500 | _O(n<sup>3</sup>)_ | Ad-hoc / DP / Greedy / Divide and Conquer / Branch and Bound  |
| 90 | _O(n<sup>4</sup>)_ | Ad-hoc / DP / Greedy / Divide and Conquer / Branch and Bound |
| 50 | _O(n<sup>5</sup>)_ | Branch and Bound |
| 40 | _O(nx2<sup>n/2</sup>)_ | 	Meet in the Middle |
| 20 | _O(n×2<sup>n</sup>)_ | Backtracking / Generating 2<sup>n</sup> Subsets / Bitmask Technique |
| 11 | _O(n!)_ | Factorial / Permutation / Combination Algorithm |

## Bit Manipulation
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1310 | [XOR Queries of a Subarray](https://leetcode.com/problems/xor-queries-of-a-subarray/) | [C++](./C++/xor-queries-of-a-subarray.cpp) [Python](./Python/xor-queries-of-a-subarray.py) | _O(n)_ | _O(1)_ | Medium ||
1318 | [Minimum Flips to Make a OR b Equal to c](https://leetcode.com/problems/minimum-flips-to-make-a-or-b-equal-to-c/) | [C++](./C++/minimum-flips-to-make-a-or-b-equal-to-c.cpp) [Python](./Python/minimum-flips-to-make-a-or-b-equal-to-c.py) | _O(1)_ | _O(1)_ | Medium ||
1342 | [Number of Steps to Reduce a Number to Zero](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero/) | [C++](./C++/number-of-steps-to-reduce-a-number-to-zero.cpp) [Python](./Python/number-of-steps-to-reduce-a-number-to-zero.py) | _O(logn)_ | _O(1)_ | Easy ||
1558 | [Minimum Numbers of Function Calls to Make Target Array](https://leetcode.com/problems/minimum-numbers-of-function-calls-to-make-target-array/) | [C++](./C++/minimum-numbers-of-function-calls-to-make-target-array.cpp) [Python](./Python/minimum-numbers-of-function-calls-to-make-target-array.py) | _O(nlogn)_ | _O(1)_ | Medium || Greedy
1707 | [Maximum XOR With an Element From Array](https://leetcode.com/problems/maximum-xor-with-an-element-from-array/) | [C++](./C++/maximum-xor-with-an-element-from-array.cpp) [Python](./Python/maximum-xor-with-an-element-from-array.py) | _O(nlogn + mlogm + nlogk + mlogk)_ | _O(nlogk)_ | Hard | variant of [Maximum XOR of Two Numbers in an Array](https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/) | Greedy, Trie
1720 | [Decode XORed Array](https://leetcode.com/problems/decode-xored-array/) | [C++](./C++/decode-xored-array.cpp) [Python](./Python/decode-xored-array.py) | _O(n)_ | _O(1)_ | Easy ||
1734 | [Decode XORed Permutation](https://leetcode.com/problems/decode-xored-permutation/) | [C++](./C++/decode-xored-permutation.cpp) [Python](./Python/decode-xored-permutation.py) | _O(n)_ | _O(1)_ | Medium ||
1829 | [Maximum XOR for Each Query](https://leetcode.com/problems/maximum-xor-for-each-query/) | [C++](./C++/maximum-xor-for-each-query.cpp) [Python](./Python/maximum-xor-for-each-query.py) | _O(n)_ | _O(1)_ | Medium ||
2151 | [Maximum Good People Based on Statements](https://leetcode.com/problems/maximum-good-people-based-on-statements/) | [C++](./C++/maximum-good-people-based-on-statements.cpp) [Python](./Python/maximum-good-people-based-on-statements.py) | _O(n^2 * 2^n)_ | _O(1)_ | Hard || Bitmask, Brute Force

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Array
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1002 | [Find Common Characters](https://leetcode.com/problems/find-common-characters/) | [C++](./C++/find-common-characters.cpp) [Python](./Python/find-common-characters.py) | _O(n * l)_ | _O(1)_      | Easy         ||
1007 | [Minimum Domino Rotations For Equal Row](https://leetcode.com/problems/minimum-domino-rotations-for-equal-row/) | [C++](./C++/minimum-domino-rotations-for-equal-row.cpp) [Python](./Python/minimum-domino-rotations-for-equal-row.py) | _O(n)_ | _O(1)_      | Medium         ||
1010 | [Pairs of Songs With Total Durations Divisible by 60](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/) | [C++](./C++/pairs-of-songs-with-total-durations-divisible-by-60.cpp) [Python](./Python/pairs-of-songs-with-total-durations-divisible-by-60.py) | _O(n)_ | _O(1)_      | Easy         ||
1013 | [Partition Array Into Three Parts With Equal Sum](https://leetcode.com/problems/partition-array-into-three-parts-with-equal-sum/) | [C++](./C++/partition-array-into-three-parts-with-equal-sum.cpp) [Python](./Python/partition-array-into-three-parts-with-equal-sum.py) | _O(n)_ | _O(1)_      | Easy         ||
1014 | [Best Sightseeing Pair](https://leetcode.com/problems/best-sightseeing-pair/) | [C++](./C++/best-sightseeing-pair.cpp) [Python](./Python/best-sightseeing-pair.py) | _O(n)_ | _O(1)_      | Medium         ||
1018 | [Binary Prefix Divisible By 5](https://leetcode.com/problems/binary-prefix-divisible-by-5/) | [C++](./C++/binary-prefix-divisible-by-5.cpp) [Python](./Python/binary-prefix-divisible-by-5.py) | _O(n)_ | _O(1)_      | Easy         ||
1030 | [Matrix Cells in Distance Order](https://leetcode.com/problems/matrix-cells-in-distance-order/) | [C++](./C++/matrix-cells-in-distance-order.cpp) [Python](./Python/matrix-cells-in-distance-order.py) | _O(m * n)_ | _O(1)_      | Easy         ||
1031 | [Maximum Sum of Two Non-Overlapping Subarrays](https://leetcode.com/problems/maximum-sum-of-two-non-overlapping-subarrays/) | [C++](./C++/maximum-sum-of-two-non-overlapping-subarrays.cpp) [Python](./Python/maximum-sum-of-two-non-overlapping-subarrays.py) | _O(n)_ | _O(1)_      | Medium         ||
1051 | [Height Checker](https://leetcode.com/problems/height-checker/) | [C++](./C++/height-checker.cpp) [Python](./Python/height-checker.py) | _O(nlogn)_ | _O(n)_      | Easy         ||
1052 | [Grumpy Bookstore Owner](https://leetcode.com/problems/grumpy-bookstore-owner/) | [C++](./C++/grumpy-bookstore-owner.cpp) [Python](./Python/grumpy-bookstore-owner.py) | _O(n)_ | _O(1)_      | Medium         ||
1072 | [Flip Columns For Maximum Number of Equal Rows](https://leetcode.com/problems/flip-columns-for-maximum-number-of-equal-rows/) | [C++](./C++/flip-columns-for-maximum-number-of-equal-rows.cpp) [Python](./Python/flip-columns-for-maximum-number-of-equal-rows.py) | _O(m * n)_ | _O(m * n)_      | Medium         ||
1074 | [Number of Submatrices That Sum to Target](https://leetcode.com/problems/number-of-submatrices-that-sum-to-target/) | [C++](./C++/number-of-submatrices-that-sum-to-target.cpp) [Python](./Python/number-of-submatrices-that-sum-to-target.py) | _O(m^2 * n)_ | _O(n)_      | Hard         ||
1085 | [Sum of Digits in the Minimum Number](https://leetcode.com/problems/sum-of-digits-in-the-minimum-number/) | [C++](./C++/sum-of-digits-in-the-minimum-number.cpp) [Python](./Python/sum-of-digits-in-the-minimum-number.py) | _O(n * l)_ | _O(l)_      | Easy         |🔒||
1089 | [Duplicate Zeros](https://leetcode.com/problems/duplicate-zeros/) | [C++](./C++/duplicate-zeros.cpp) [Python](./Python/duplicate-zeros.py) | _O(n)_ | _O(1)_      | Easy         ||
1093 | [Statistics from a Large Sample](https://leetcode.com/problems/statistics-from-a-large-sample/) | [C++](./C++/statistics-from-a-large-sample.cpp) [Python](./Python/statistics-from-a-large-sample.py) | _O(n)_ | _O(1)_      | Medium         ||
1099 | [Two Sum Less Than K](https://leetcode.com/problems/two-sum-less-than-k/) | [C++](./C++/two-sum-less-than-k.cpp) [Python](./Python/two-sum-less-than-k.py) | _O(nlogn)_ | _O(1)_      | Easy         |🔒|
1109 | [Corporate Flight Bookings](https://leetcode.com/problems/corporate-flight-bookings/) | [C++](./C++/corporate-flight-bookings.cpp) [Python](./Python/corporate-flight-bookings.py) | _O(n)_ | _O(1)_      | Medium         || Line Sweep
1144 | [Decrease Elements To Make Array Zigzag](https://leetcode.com/problems/decrease-elements-to-make-array-zigzag/) | [C++](./C++/decrease-elements-to-make-array-zigzag.cpp) [Python](./Python/decrease-elements-to-make-array-zigzag.py) | _O(n)_ | _O(1)_      | Medium         ||
1184 | [Distance Between Bus Stops](https://leetcode.com/problems/distance-between-bus-stops/) | [C++](./C++/distance-between-bus-stops.cpp) [Python](./Python/distance-between-bus-stops.py) | _O(n)_ | _O(1)_      | Easy         || 
1200 | [Minimum Absolute Difference](https://leetcode.com/problems/minimum-absolute-difference/) | [C++](./C++/minimum-absolute-difference.cpp) [Python](./Python/minimum-absolute-difference.py) | _O(nlogn)_ | _O(n)_      | Easy         || 
1222 | [Queens That Can Attack the King](https://leetcode.com/problems/queens-that-can-attack-the-king/) | [C++](./C++/queens-that-can-attack-the-king.cpp) [Python](./Python/queens-that-can-attack-the-king.py) | _O(1)_ | _O(1)_      | Medium         || 
1252 | [Cells with Odd Values in a Matrix](https://leetcode.com/problems/cells-with-odd-values-in-a-matrix/) | [C++](./C++/cells-with-odd-values-in-a-matrix.cpp) [Python](./Python/cells-with-odd-values-in-a-matrix.py) | _O(n + m)_ | _O(n + m)_      | Easy         || 
1260 | [Shift 2D Grid](https://leetcode.com/problems/shift-2d-grid/) | [C++](./C++/shift-2d-grid.cpp) [Python](./Python/shift-2d-grid.py) | _O(n)_ | _O(1)_      | Easy         || 
1267 | [Count Servers that Communicate](https://leetcode.com/problems/count-servers-that-communicate/) | [C++](./C++/count-servers-that-communicate.cpp) [Python](./Python/count-servers-that-communicate.py) | _O(m * n)_ | _O(m + n)_      | Medium         || 
1275 | [Find Winner on a Tic Tac Toe Game](https://leetcode.com/problems/find-winner-on-a-tic-tac-toe-game/) | [C++](./C++/find-winner-on-a-tic-tac-toe-game.cpp) [Python](./Python/find-winner-on-a-tic-tac-toe-game.py) | _O(1)_ | _O(1)_      | Easy         || 
1295 | [Find Numbers with Even Number of Digits](https://leetcode.com/problems/find-numbers-with-even-number-of-digits/) | [C++](./C++/find-numbers-with-even-number-of-digits.cpp) [Python](./Python/find-numbers-with-even-number-of-digits.py) | _O(nlog(logm))_ | _O(logm)_      | Easy         || 
1299 | [Replace Elements with Greatest Element on Right Side](https://leetcode.com/problems/replace-elements-with-greatest-element-on-right-side/) | [C++](./C++/replace-elements-with-greatest-element-on-right-side.cpp) [Python](./Python/replace-elements-with-greatest-element-on-right-side.py) | _O(n)_ | _O(1)_      | Easy         || 
1304 | [Find N Unique Integers Sum up to Zero](https://leetcode.com/problems/find-n-unique-integers-sum-up-to-zero/) | [C++](./C++/find-n-unique-integers-sum-up-to-zero.cpp) [Python](./Python/find-n-unique-integers-sum-up-to-zero.py) | _O(n)_ | _O(1)_      | Easy         || 
1313 | [Decompress Run-Length Encoded List](https://leetcode.com/problems/decompress-run-length-encoded-list/) | [C++](./C++/decompress-run-length-encoded-list.cpp) [Python](./Python/decompress-run-length-encoded-list.py) | _O(n)_ | _O(1)_      | Easy         || 
1329 | [Sort the Matrix Diagonally](https://leetcode.com/problems/sort-the-matrix-diagonally/) | [C++](./C++/sort-the-matrix-diagonally.cpp) [Python](./Python/sort-the-matrix-diagonally.py) | _O(m * n * log(min(m, n))_ | _O(m * n)_      | Medium         || Sort
1331 | [Rank Transform of an Array](https://leetcode.com/problems/rank-transform-of-an-array/) | [C++](./C++/rank-transform-of-an-array.cpp) [Python](./Python/rank-transform-of-an-array.py) | _O(nlogn)_ | _O(n)_      | Easy         || 
1333 | [Filter Restaurants by Vegan-Friendly, Price and Distance](https://leetcode.com/problems/filter-restaurants-by-vegan-friendly-price-and-distance/) | [C++](./C++/filter-restaurants-by-vegan-friendly-price-and-distance.cpp) [Python](./Python/filter-restaurants-by-vegan-friendly-price-and-distance.py) | _O(rlogr)_ | _O(r)_      | Medium         || Sort
1337 | [The K Weakest Rows in a Matrix](https://leetcode.com/problems/the-k-weakest-rows-in-a-matrix/) | [C++](./C++/the-k-weakest-rows-in-a-matrix.cpp) [Python](./Python/the-k-weakest-rows-in-a-matrix.py) | _O(m * n)_ | _O(k)_      | Easy         || OrderedDict, Quick Select
1343 | [Number of Sub-arrays of Size K and Average Greater than or Equal to Threshold](https://leetcode.com/problems/number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold/) | [C++](./C++/number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold.cpp) [Python](./Python/number-of-sub-arrays-of-size-k-and-average-greater-than-or-equal-to-threshold.py) | _O(n)_ | _O(1)_      | Medium         || 
1346 | [Check If N and Its Double Exist](https://leetcode.com/problems/check-if-n-and-its-double-exist/) | [C++](./C++/check-if-n-and-its-double-exist.cpp) [Python](./Python/check-if-n-and-its-double-exist.py) | _O(n)_ | _O(n)_      | Easy         || 
1351 | [Count Negative Numbers in a Sorted Matrix](https://leetcode.com/problems/count-negative-numbers-in-a-sorted-matrix/) | [C++](./C++/count-negative-numbers-in-a-sorted-matrix.cpp) [Python](./Python/count-negative-numbers-in-a-sorted-matrix.py) | _O(m + n)_ | _O(1)_      | Easy         || 
1375 | [Bulb Switcher III](https://leetcode.com/problems/bulb-switcher-iii/) | [C++](./C++/bulb-switcher-iii.cpp) [Python](./Python/bulb-switcher-iii.py) | _O(n)_ | _O(1)_      | Medium         ||
1380 | [Lucky Numbers in a Matrix](https://leetcode.com/problems/lucky-numbers-in-a-matrix/) | [C++](./C++/lucky-numbers-in-a-matrix.cpp) [Python](./Python/lucky-numbers-in-a-matrix.py) | _O(m * n)_ | _O(m + n)_      | Easy         ||
1389 | [Create Target Array in the Given Order](https://leetcode.com/problems/create-target-array-in-the-given-order/) | [C++](./C++/create-target-array-in-the-given-order.cpp) [Python](./Python/create-target-array-in-the-given-order.py) | _O(n^2)_ | _O(1)_      | Easy         ||
1394 | [Find Lucky Integer in an Array](https://leetcode.com/problems/find-lucky-integer-in-an-array/) | [C++](./C++/find-lucky-integer-in-an-array.cpp) [Python](./Python/find-lucky-integer-in-an-array.py) | _O(n)_ | _O(n)_      | Easy         ||
1399 | [Count Largest Group](https://leetcode.com/problems/count-largest-group/) | [C++](./C++/count-largest-group.cpp) [Python](./Python/count-largest-group.py) | _O(nlogn)_ | _O(n)_      | Easy         ||
1404 | [Number of Steps to Reduce a Number in Binary Representation to One](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-in-binary-representation-to-one/) | [C++](./C++/number-of-steps-to-reduce-a-number-in-binary-representation-to-one.cpp) [Python](./Python/number-of-steps-to-reduce-a-number-in-binary-representation-to-one.py) | _O(n)_ | _O(1)_      | Medium         ||
1413 | [Minimum Value to Get Positive Step by Step Sum](https://leetcode.com/problems/minimum-value-to-get-positive-step-by-step-sum/) | [C++](./C++/minimum-value-to-get-positive-step-by-step-sum.cpp) [Python](./Python/minimum-value-to-get-positive-step-by-step-sum.py) | _O(n)_ | _O(1)_      | Easy         ||
1426 | [Counting Elements](https://leetcode.com/problems/counting-elements/)| [C++](./C++/counting-elements.cpp) [Python](./Python/counting-elements.py) | _O(n)_      | _O(n)_          | Easy         | 🔒 |
1427 | [Perform String Shifts](https://leetcode.com/problems/perform-string-shifts/)| [C++](./C++/perform-string-shifts.cpp) [Python](./Python/perform-string-shifts.py) | _O(n + l)_      | _O(1)_          | Easy         | 🔒 |
1428 | [Leftmost Column with at Least a One](https://leetcode.com/problems/leftmost-column-with-at-least-a-one/)| [C++](./C++/leftmost-column-with-at-least-a-one.cpp) [Python](./Python/leftmost-column-with-at-least-a-one.py) | _O(m + n)_      | _O(1)_          | Medium         | 🔒 |
1431 | [Kids With the Greatest Number of Candies](https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/) | [C++](./C++/kids-with-the-greatest-number-of-candies.cpp) [Python](./Python/kids-with-the-greatest-number-of-candies.py) | _O(n)_ | _O(1)_      | Easy         || 
1437 | [Check If All 1's Are at Least Length K Places Away](https://leetcode.com/problems/check-if-all-1s-are-at-least-length-k-places-away/) | [C++](./C++/check-if-all-1s-are-at-least-length-k-places-away.cpp) [Python](./Python/check-if-all-1s-are-at-least-length-k-places-away.py) | _O(n)_ | _O(1)_      | Medium         || 
1450 | [Number of Students Doing Homework at a Given Time](https://leetcode.com/problems/number-of-students-doing-homework-at-a-given-time/) | [C++](./C++/number-of-students-doing-homework-at-a-given-time.cpp) [Python](./Python/number-of-students-doing-homework-at-a-given-time.py) | _O(n)_ | _O(1)_      | Easy         || 
1460 | [Make Two Arrays Equal by Reversing Sub-arrays](https://leetcode.com/problems/make-two-arrays-equal-by-reversing-sub-arrays/) | [C++](./C++/make-two-arrays-equal-by-reversing-sub-arrays.cpp) [Python](./Python/make-two-arrays-equal-by-reversing-sub-arrays.py) | _O(n)_ | _O(n)_      | Easy         || 
1464 | [Maximum Product of Two Elements in an Array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array/) | [C++](./C++/maximum-product-of-two-elements-in-an-array.cpp) [Python](./Python/maximum-product-of-two-elements-in-an-array.py) | _O(n)_ | _O(1)_      | Easy         || 
1465 | [Maximum Area of a Piece of Cake After Horizontal and Vertical Cuts](https://leetcode.com/problems/maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts/) | [C++](./C++/maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts.cpp) [Python](./Python/maximum-area-of-a-piece-of-cake-after-horizontal-and-vertical-cuts.py) | _O(hlogh + wlogw)_ | _O(1)_      | Medium         || 
1470 | [Shuffle the Array](https://leetcode.com/problems/shuffle-the-array/) | [C++](./C++/shuffle-the-array.cpp) [Python](./Python/shuffle-the-array.py) | _O(n)_ | _O(1)_      | Easy         ||
1471 | [The k Strongest Values in an Array](https://leetcode.com/problems/the-k-strongest-values-in-an-array/) | [C++](./C++/the-k-strongest-values-in-an-array.cpp) [Python](./Python/the-k-strongest-values-in-an-array.py) | _O(n)_ | _O(1)_      | Medium         || Quick Select
1475 | [Final Prices With a Special Discount in a Shop](https://leetcode.com/problems/final-prices-with-a-special-discount-in-a-shop/) | [C++](./C++/final-prices-with-a-special-discount-in-a-shop.cpp) [Python](./Python/final-prices-with-a-special-discount-in-a-shop.py) | _O(n)_ | _O(n)_      | Easy         || Mono Stack
1480 | [Running Sum of 1d Array](https://leetcode.com/problems/running-sum-of-1d-array/) | [C++](./C++/running-sum-of-1d-array.cpp) [Python](./Python/running-sum-of-1d-array.py) | _O(n)_ | _O(1)_      | Easy         ||
1491 | [Average Salary Excluding the Minimum and Maximum Salary](https://leetcode.com/problems/average-salary-excluding-the-minimum-and-maximum-salary/) | [C++](./C++/average-salary-excluding-the-minimum-and-maximum-salary.cpp) [Python](./Python/average-salary-excluding-the-minimum-and-maximum-salary.py) | _O(n)_ | _O(1)_      | Easy         ||
1502 | [Can Make Arithmetic Progression From Sequence](https://leetcode.com/problems/can-make-arithmetic-progression-from-sequence/) | [C++](./C++/can-make-arithmetic-progression-from-sequence.cpp) [Python](./Python/can-make-arithmetic-progression-from-sequence.py) | _O(n)_ | _O(1)_      | Easy         ||
1503 | [Last Moment Before All Ants Fall Out of a Plank](https://leetcode.com/problems/last-moment-before-all-ants-fall-out-of-a-plank/) | [C++](./C++/last-moment-before-all-ants-fall-out-of-a-plank.cpp) [Python](./Python/last-moment-before-all-ants-fall-out-of-a-plank.py) | _O(n)_ | _O(1)_      | Medium         ||
1534 | [Count Good Triplets](https://leetcode.com/problems/count-good-triplets/) | [C++](./C++/count-good-triplets.cpp) [Python](./Python/count-good-triplets.py) | _O(n^3)_ | _O(1)_      | Easy         ||
1535 | [Find the Winner of an Array Game](https://leetcode.com/problems/find-the-winner-of-an-array-game/) | [C++](./C++/find-the-winner-of-an-array-game.cpp) [Python](./Python/find-the-winner-of-an-array-game.py) | _O(n)_ | _O(1)_      | Medium         ||
1538 | [Guess the Majority in a Hidden Array](https://leetcode.com/problems/guess-the-majority-in-a-hidden-array/) | [C++](./C++/guess-the-majority-in-a-hidden-array.cpp) [Python](./Python/guess-the-majority-in-a-hidden-array.py) | _O(n)_ | _O(1)_      | Medium         |🔒|
1550 | [Three Consecutive Odds](https://leetcode.com/problems/three-consecutive-odds/) | [C++](./C++/three-consecutive-odds.cpp) [Python](./Python/three-consecutive-odds.py) | _O(n)_ | _O(1)_      | Easy         ||
1559 | [Detect Cycles in 2D Grid](https://leetcode.com/problems/detect-cycles-in-2d-grid/) | [C++](./C++/detect-cycles-in-2d-grid.cpp) [Python](./Python/detect-cycles-in-2d-grid.py) | _O(m * n)_ | _O(m * n)_      | Hard         || Union Find, BFS
1560 | [Most Visited Sector in a Circular Track](https://leetcode.com/problems/most-visited-sector-in-a-circular-track/) | [C++](./C++/most-visited-sector-in-a-circular-track.cpp) [Python](./Python/most-visited-sector-in-a-circular-track.py) | _O(n)_ | _O(1)_      | Easy         ||
1562 | [Find Latest Group of Size M](https://leetcode.com/problems/find-latest-group-of-size-m/) | [C++](./C++/find-latest-group-of-size-m.cpp) [Python](./Python/find-latest-group-of-size-m.py) | _O(n)_ | _O(n)_      | Medium         ||
1566 | [Detect Pattern of Length M Repeated K or More Times](https://leetcode.com/problems/detect-pattern-of-length-m-repeated-k-or-more-times/) | [C++](./C++/detect-pattern-of-length-m-repeated-k-or-more-times.cpp) [Python](./Python/detect-pattern-of-length-m-repeated-k-or-more-times.py) | _O(n)_ | _O(1)_      | Easy         ||
1572 | [Matrix Diagonal Sum](https://leetcode.com/problems/matrix-diagonal-sum/) | [C++](./C++/matrix-diagonal-sum.cpp) [Python](./Python/matrix-diagonal-sum.py) | _O(n)_ | _O(1)_      | Easy         ||
1574 | [Shortest Subarray to be Removed to Make Array Sorted](https://leetcode.com/problems/shortest-subarray-to-be-removed-to-make-array-sorted/) | [C++](./C++/shortest-subarray-to-be-removed-to-make-array-sorted.cpp) [Python](./Python/shortest-subarray-to-be-removed-to-make-array-sorted.py) | _O(n)_ | _O(1)_      | Medium         ||
1582 | [Special Positions in a Binary Matrix](https://leetcode.com/problems/special-positions-in-a-binary-matrix/) | [C++](./C++/special-positions-in-a-binary-matrix.cpp) [Python](./Python/special-positions-in-a-binary-matrix.py) | _O(n^2)_ | _O(n)_      | Easy         ||
1583 | [Count Unhappy Friends](https://leetcode.com/problems/count-unhappy-friends/) | [C++](./C++/count-unhappy-friends.cpp) [Python](./Python/count-unhappy-friends.py) | _O(n^2)_ | _O(n^2)_      | Medium         ||
1619 | [Mean of Array After Removing Some Elements](https://leetcode.com/problems/mean-of-array-after-removing-some-elements/) | [C++](./C++/mean-of-array-after-removing-some-elements.cpp) [Python](./Python/mean-of-array-after-removing-some-elements.py) | _O(n)_ | _O(1)_      | Easy         || Quick Select
1629 | [Slowest Key](https://leetcode.com/problems/slowest-key/) | [C++](./C++/slowest-key.cpp) [Python](./Python/slowest-key.py) | _O(n)_ | _O(1)_      | Easy         ||
1646 | [Get Maximum in Generated Array](https://leetcode.com/problems/get-maximum-in-generated-array/) | [C++](./C++/get-maximum-in-generated-array.cpp) [Python](./Python/get-maximum-in-generated-array.py) | _O(n)_ | _O(n)_ | Easy ||
1652 | [Defuse the Bomb](https://leetcode.com/problems/defuse-the-bomb/) | [C++](./C++/defuse-the-bomb.cpp) [Python](./Python/defuse-the-bomb.py) | _O(n)_ | _O(1)_ | Easy ||
1672 | [Richest Customer Wealth](https://leetcode.com/problems/richest-customer-wealth/) | [C++](./C++/richest-customer-wealth.cpp) [Python](./Python/richest-customer-wealth.py) | _O(m * n)_ | _O(1)_ | Easy ||
1700 | [Number of Students Unable to Eat Lunch](https://leetcode.com/problems/number-of-students-unable-to-eat-lunch/) | [C++](./C++/number-of-students-unable-to-eat-lunch.cpp) [Python](./Python/number-of-students-unable-to-eat-lunch.py) | _O(n)_ | _O(1)_ | Easy ||
1701 | [Average Waiting Time](https://leetcode.com/problems/average-waiting-time/) | [C++](./C++/average-waiting-time.cpp) [Python](./Python/average-waiting-time.py) | _O(n)_ | _O(1)_ | Medium ||
1706 | [Where Will the Ball Fall](https://leetcode.com/problems/where-will-the-ball-fall/) | [C++](./C++/where-will-the-ball-fall.cpp) [Python](./Python/where-will-the-ball-fall.py) | _O(m * n)_ | _O(1)_ | Medium ||
1714 | [Sum Of Special Evenly-Spaced Elements In Array](https://leetcode.com/problems/sum-of-special-evenly-spaced-elements-in-array/) | [C++](./C++/sum-of-special-evenly-spaced-elements-in-array.cpp) [Python](./Python/sum-of-special-evenly-spaced-elements-in-array.py) | _O(n * sqrt(n))_ | _O(n * sqrt(n))_ | Hard | 	🔒 |
1726 | [Tuple with Same Product](https://leetcode.com/problems/tuple-with-same-product/) | [C++](./C++/tuple-with-same-product.cpp) [Python](./Python/tuple-with-same-product.py) | _O(n^2)_ | _O(n^2)_ | Medium ||
1732 | [Find the Highest Altitude](https://leetcode.com/problems/find-the-highest-altitude/) | [C++](./C++/find-the-highest-altitude.cpp) [Python](./Python/find-the-highest-altitude.py) | _O(n)_ | _O(1)_ | Medium ||
1738 | [Find Kth Largest XOR Coordinate Value](https://leetcode.com/problems/find-kth-largest-xor-coordinate-value/) | [C++](./C++/find-kth-largest-xor-coordinate-value.cpp) [Python](./Python/find-kth-largest-xor-coordinate-value.py) | _O(m * n)_ on average | _O(m * n)_ | Medium || Quick Select
1742 | [Maximum Number of Balls in a Box](https://leetcode.com/problems/maximum-number-of-balls-in-a-box/) | [C++](./C++/maximum-number-of-balls-in-a-box.cpp) [Python](./Python/maximum-number-of-balls-in-a-box.py) | _O(nlogm)_ | _O(logm)_ | Easy ||
1752 | [Check if Array Is Sorted and Rotated](https://leetcode.com/problems/check-if-array-is-sorted-and-rotated/) | [C++](./C++/check-if-array-is-sorted-and-rotated.cpp) [Python](./Python/check-if-array-is-sorted-and-rotated.py) | _O(n)_ | _O(1)_ | Easy ||
1755 | [Closest Subsequence Sum](https://leetcode.com/problems/closest-subsequence-sum/) | [C++](./C++/closest-subsequence-sum.cpp) [Python](./Python/closest-subsequence-sum.py) | _O(n * 2^(n/2))_ | _O(2^(n/2))_ | Hard || Meet in the Middle
1773 | [Count Items Matching a Rule](https://leetcode.com/problems/count-items-matching-a-rule/) | [C++](./C++/count-items-matching-a-rule.cpp) [Python](./Python/count-items-matching-a-rule.py) | _O(n)_ | _O(1)_ | Easy ||
1779 | [Find Nearest Point That Has the Same X or Y Coordinate](https://leetcode.com/problems/find-nearest-point-that-has-the-same-x-or-y-coordinate/) | [C++](./C++/find-nearest-point-that-has-the-same-x-or-y-coordinate.cpp) [Python](./Python/find-nearest-point-that-has-the-same-x-or-y-coordinate.py) | _O(n)_ | _O(1)_ | Easy ||
1800 | [Maximum Ascending Subarray Sum](https://leetcode.com/problems/maximum-ascending-subarray-sum/) | [C++](./C++/maximum-ascending-subarray-sum.cpp) [Python](./Python/maximum-ascending-subarray-sum.py) | _O(n)_ | _O(1)_ | Easy ||
1826 | [Faulty Sensor](https://leetcode.com/problems/faulty-sensor/) | [C++](./C++/faulty-sensor.cpp) [Python](./Python/faulty-sensor.py) | _O(n)_ | _O(1)_ | Easy |🔒||
1848 | [Minimum Distance to the Target Element](https://leetcode.com/problems/minimum-distance-to-the-target-element/) | [C++](./C++/minimum-distance-to-the-target-element.cpp) [Python](./Python/minimum-distance-to-the-target-element.py) | _O(n)_ | _O(1)_ | Easy ||
1861 | [Rotating the Box](https://leetcode.com/problems/rotating-the-box/) | [C++](./C++/rotating-the-box.cpp) [Python](./Python/rotating-the-box.py) | _O(m * n)_ | _O(1)_ | Medium ||
1869 | [Longer Contiguous Segments of Ones than Zeros](https://leetcode.com/problems/longer-contiguous-segments-of-ones-than-zeros/) | [C++](./C++/longer-contiguous-segments-of-ones-than-zeros.cpp) [Python](./Python/longer-contiguous-segments-of-ones-than-zeros.py) | _O(n)_ | _O(1)_ | Easy ||
1878 | [Get Biggest Three Rhombus Sums in a Grid](https://leetcode.com/problems/get-biggest-three-rhombus-sums-in-a-grid/) | [C++](./C++/get-biggest-three-rhombus-sums-in-a-grid.cpp) [Python](./Python/get-biggest-three-rhombus-sums-in-a-grid.py) | _O(m * n * min(m, n))_ | _O(m * n)_ | Easy ||
1886 | [Determine Whether Matrix Can Be Obtained By Rotation](https://leetcode.com/problems/determine-whether-matrix-can-be-obtained-by-rotation/) | [C++](./C++/determine-whether-matrix-can-be-obtained-by-rotation.cpp) [Python](./Python/determine-whether-matrix-can-be-obtained-by-rotation.py) | _O(m * n)_ | _O(1)_ | Easy ||
1895 | [Largest Magic Square](https://leetcode.com/problems/largest-magic-square/) | [C++](./C++/largest-magic-square.cpp) [Python](./Python/largest-magic-square.py) | _O(max(m, n) * min(m, n)^3)_ | _O(m * n)_ | Medium ||
1906 | [Minimum Absolute Difference Queries](https://leetcode.com/problems/minimum-absolute-difference-queries/) | [C++](./C++/minimum-absolute-difference-queries.cpp) [Python](./Python/minimum-absolute-difference-queries.py) | _O(r * (n + q))_ | _O(r * n)_ | Medium || Prefix Sum, Binary Search
1909 | [Remove One Element to Make the Array Strictly Increasing](https://leetcode.com/problems/remove-one-element-to-make-the-array-strictly-increasing/) | [C++](./C++/remove-one-element-to-make-the-array-strictly-increasing.cpp) [Python](./Python/remove-one-element-to-make-the-array-strictly-increasing.py) | _O(n)_ | _O(1)_ | Easy ||
1914 | [Cyclically Rotating a Grid](https://leetcode.com/problems/cyclically-rotating-a-grid/) | [C++](./C++/cyclically-rotating-a-grid.cpp) [Python](./Python/cyclically-rotating-a-grid.py) | _O(m * n)_ | _O(1)_ | Medium || Inplace
1920 | [Build Array from Permutation](https://leetcode.com/problems/build-array-from-permutation/) | [C++](./C++/build-array-from-permutation.cpp) [Python](./Python/build-array-from-permutation.py) | _O(n)_ | _O(1)_ | Easy || Inplace
1929 | [Concatenation of Array](https://leetcode.com/problems/concatenation-of-array/) | [C++](./C++/concatenation-of-array.cpp) [Python](./Python/concatenation-of-array.py) | _O(n)_ | _O(1)_ | Easy ||
1940 | [Longest Common Subsequence Between Sorted Arrays](https://leetcode.com/problems/longest-common-subsequence-between-sorted-arrays/) | [C++](./C++/longest-common-subsequence-between-sorted-arrays.cpp) [Python](./Python/longest-common-subsequence-between-sorted-arrays.py) | _O(m * n)_ | _O(l)_ | Medium | 🔒 |
1958 | [Check if Move is Legal](https://leetcode.com/problems/check-if-move-is-legal/) | [C++](./C++/check-if-move-is-legal.cpp) [Python](./Python/check-if-move-is-legal.py) | _O(1)_ | _O(1)_ | Medium | |
1966 | [Binary Searchable Numbers in an Unsorted Array](https://leetcode.com/problems/binary-searchable-numbers-in-an-unsorted-array/) | [C++](./C++/binary-searchable-numbers-in-an-unsorted-array.cpp) [Python](./Python/binary-searchable-numbers-in-an-unsorted-array.py) | _O(n)_ | _O(n)_ | Medium |🔒| Prefix Sum |
1970 | [Last Day Where You Can Still Cross](https://leetcode.com/problems/last-day-where-you-can-still-cross/) | [C++](./C++/last-day-where-you-can-still-cross.cpp) [Python](./Python/last-day-where-you-can-still-cross.py) | _O(m * n)_ | _O(m * n)_ | Hard | variant of [Bricks Falling When Hit](https://leetcode.com/problems/bricks-falling-when-hit/) | Union Find
1983 | [Widest Pair of Indices With Equal Range Sum](https://leetcode.com/problems/widest-pair-of-indices-with-equal-range-sum/) | [C++](./C++/widest-pair-of-indices-with-equal-range-sum.cpp) [Python](./Python/widest-pair-of-indices-with-equal-range-sum.py) | _O(n)_ | _O(n)_ | Medium | variant of [Find the Longest Substring Containing Vowels in Even Counts](https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts/), 🔒 | Prefix Sum
1991 | [Find the Middle Index in Array](https://leetcode.com/problems/find-the-middle-index-in-array/) | [C++](./C++/find-the-middle-index-in-array.cpp) [Python](./Python/find-the-middle-index-in-array.py) | _O(n)_ | _O(1)_ | Easy | | Prefix Sum
1992 | [Find All Groups of Farmland](https://leetcode.com/problems/find-all-groups-of-farmland/) | [C++](./C++/find-all-groups-of-farmland.cpp) [Python](./Python/find-all-groups-of-farmland.py) | _O(m * n)_ | _O(1)_ | Medium | variant of [Number of Islands](https://leetcode.com/problems/number-of-islands/) | 
1998 | [GCD Sort of an Array](https://leetcode.com/problems/gcd-sort-of-an-array/) | [C++](./C++/gcd-sort-of-an-array.cpp) [Python](./Python/gcd-sort-of-an-array.py) | _O(nlogn + m)_ | _O(n + m)_ | Hard |  | Union Find, `Sieve of Eratosthenes`
2007 | [Find Original Array From Doubled Array](https://leetcode.com/problems/find-original-array-from-doubled-array/) | [C++](./C++/find-original-array-from-doubled-array.cpp) [Python](./Python/find-original-array-from-doubled-array.py) | _O(n + klogk)_ | _O(k)_      | Medium         | variant of [Array of Doubled Pairs](https://leetcode.com/problems/array-of-doubled-pairs/) |
2011 | [Final Value of Variable After Performing Operations](https://leetcode.com/problems/final-value-of-variable-after-performing-operations/) | [C++](./C++/final-value-of-variable-after-performing-operations.cpp) [Python](./Python/final-value-of-variable-after-performing-operations.py) | _O(n)_ | _O(1)_      | Easy         | |
2012 | [Sum of Beauty in the Array](https://leetcode.com/problems/sum-of-beauty-in-the-array/) | [C++](./C++/sum-of-beauty-in-the-array.cpp) [Python](./Python/sum-of-beauty-in-the-array.py) | _O(n)_ | _O(n)_ | Medium || Prefix Sum
2016 | [Maximum Difference Between Increasing Elements](https://leetcode.com/problems/maximum-difference-between-increasing-elements/)| [C++](./C++/maximum-difference-between-increasing-elements.cpp) [Python](./Python/maximum-difference-between-increasing-elements.py) | _O(n)_ | _O(1)_ | Easy | variant of [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) |
2017 | [Grid Game](https://leetcode.com/problems/grid-game/) | [C++](./C++/grid-game.cpp) [Python](./Python/grid-game.py) | _O(n)_ | _O(1)_ | Medium || Prefix Sum
2018 | [Check if Word Can Be Placed In Crossword](https://leetcode.com/problems/check-if-word-can-be-placed-in-crossword/) | [C++](./C++/check-if-word-can-be-placed-in-crossword.cpp) [Python](./Python/check-if-word-can-be-placed-in-crossword.py) | _O(m * n)_ | _O(1)_ | Medium ||
2022 | [Convert 1D Array Into 2D Array](https://leetcode.com/problems/convert-1d-array-into-2d-array/) | [C++](./C++/convert-1d-array-into-2d-array.cpp) [Python](./Python/convert-1d-array-into-2d-array.py) | _O(m * n)_ | _O(1)_ | Easy ||
2033 | [Minimum Operations to Make a Uni-Value Grid](https://leetcode.com/problems/minimum-operations-to-make-a-uni-value-grid/) | [C++](./C++/minimum-operations-to-make-a-uni-value-grid.cpp) [Python](./Python/minimum-operations-to-make-a-uni-value-grid.py) | _O(m * n)_  on average | _O(m * n)_ | Medium | variant of [Minimum Moves to Equal Array Elements II](https://leetcode.com/problems/minimum-moves-to-equal-array-elements-ii/) | Math, Median, Quick Select
2035 | [Partition Array Into Two Arrays to Minimize Sum Difference](https://leetcode.com/problems/partition-array-into-two-arrays-to-minimize-sum-difference/) | [C++](./C++/partition-array-into-two-arrays-to-minimize-sum-difference.cpp) [Python](./Python/partition-array-into-two-arrays-to-minimize-sum-difference.py) | _O(n * 2^n)_ | _O(2^n)_ | Hard || Meet in the Middle
2038 | [Remove Colored Pieces if Both Neighbors are the Same Color](https://leetcode.com/problems/remove-colored-pieces-if-both-neighbors-are-the-same-color/) | [C++](./C++/remove-colored-pieces-if-both-neighbors-are-the-same-color.cpp) [Python](./Python/remove-colored-pieces-if-both-neighbors-are-the-same-color.py) | _O(n)_ | _O(1)_ | Medium || 
2055 | [Plates Between Candles](https://leetcode.com/problems/plates-between-candles/) | [C++](./C++/plates-between-candles.cpp) [Python](./Python/plates-between-candles.py) | _O(n + q)_ | _O(n)_ | Medium || Prefix Sum 
2057 | [Smallest Index With Equal Value](https://leetcode.com/problems/smallest-index-with-equal-value/) | [C++](./C++/smallest-index-with-equal-value.cpp) [Python](./Python/smallest-index-with-equal-value.py) | _O(n)_ | _O(1)_ | Easy ||
2075 | [Decode the Slanted Ciphertext](https://leetcode.com/problems/decode-the-slanted-ciphertext/) | [C++](./C++/decode-the-slanted-ciphertext.cpp) [Python](./Python/decode-the-slanted-ciphertext.py) | _O(n)_ | _O(1)_ | Medium ||
2078 | [Two Furthest Houses With Different Colors](https://leetcode.com/problems/two-furthest-houses-with-different-colors/) | [C++](./C++/two-furthest-houses-with-different-colors.cpp) [Python](./Python/two-furthest-houses-with-different-colors.py) | _O(n)_ | _O(1)_ | Easy ||
2079 | [Watering Plants](https://leetcode.com/problems/watering-plants/) | [C++](./C++/watering-plants.cpp) [Python](./Python/watering-plants.py) | _O(n)_ | _O(1)_ | Medium ||
2098 | [Subsequence of Size K With the Largest Even Sum](https://leetcode.com/problems/subsequence-of-size-k-with-the-largest-even-sum/) | [C++](./C++/subsequence-of-size-k-with-the-largest-even-sum.cpp) [Python](./Python/subsequence-of-size-k-with-the-largest-even-sum.py) | _O(n)_ on average | _O(1)_ | Medium | 🔒 | Quick Select
2099 | [Find Subsequence of Length K With the Largest Sum](https://leetcode.com/problems/find-subsequence-of-length-k-with-the-largest-sum/) | [C++](./C++/find-subsequence-of-length-k-with-the-largest-sum.cpp) [Python](./Python/find-subsequence-of-length-k-with-the-largest-sum.py) | _O(n)_ on average | _O(n)_ | Easy | | Quick Select
2100 | [Find Good Days to Rob the Bank](https://leetcode.com/problems/find-good-days-to-rob-the-bank/) | [C++](./C++/find-good-days-to-rob-the-bank.cpp) [Python](./Python/find-good-days-to-rob-the-bank.py) | _O(n)_ | _O(n)_ | Medium | | Prefix Sum
2106 | [Maximum Fruits Harvested After at Most K Steps](https://leetcode.com/problems/maximum-fruits-harvested-after-at-most-k-steps/) | [C++](./C++/maximum-fruits-harvested-after-at-most-k-steps.cpp) [Python](./Python/maximum-fruits-harvested-after-at-most-k-steps.py) | _O(n)_ | _O(n)_ | Hard | | Prefix Sum
2113 | [Elements in Array After Removing and Replacing Elements](https://leetcode.com/problems/elements-in-array-after-removing-and-replacing-elements/) | [C++](./C++/elements-in-array-after-removing-and-replacing-elements.cpp) [Python](./Python/elements-in-array-after-removing-and-replacing-elements.py) | _O(n)_ | _O(1)_ | Medium | 🔒 |
2121 | [Intervals Between Identical Elements](https://leetcode.com/problems/intervals-between-identical-elements/) | [C++](./C++/intervals-between-identical-elements.cpp) [Python](./Python/intervals-between-identical-elements.py) | _O(n)_ | _O(n)_ | Medium | | Prefix Sum
2122 | [Recover the Original Array](https://leetcode.com/problems/recover-the-original-array/) | [C++](./C++/recover-the-original-array.cpp) [Python](./Python/recover-the-original-array.py) | _O(n^2)_ | _O(n)_ | Hard | |
2128 | [Remove All Ones With Row and Column Flips](https://leetcode.com/problems/remove-all-ones-with-row-and-column-flips/) | [C++](./C++/remove-all-ones-with-row-and-column-flips.cpp) [Python](./Python/remove-all-ones-with-row-and-column-flips.py) | _O(m * n)_ | _O(1)_ | Medium | 🔒 |
2132 | [Stamping the Grid](https://leetcode.com/problems/stamping-the-grid/) | [C++](./C++/stamping-the-grid.cpp) [Python](./Python/stamping-the-grid.py) | _O(m * n)_ | _O(m * n)_ | Hard | | Prefix Sum
2155 | [All Divisions With the Highest Score of a Binary Array](https://leetcode.com/problems/all-divisions-with-the-highest-score-of-a-binary-array/) | [C++](./C++/all-divisions-with-the-highest-score-of-a-binary-array.cpp) [Python](./Python/all-divisions-with-the-highest-score-of-a-binary-array.py) | _O(n)_ | _O(1)_ | Medium | | Prefix Sum

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## String
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1016 | [Binary String With Substrings Representing 1 To N](https://leetcode.com/problems/binary-string-with-substrings-representing-1-to-n/) | [C++](./C++/binary-string-with-substrings-representing-1-to-n.cpp) [Python](./Python/binary-string-with-substrings-representing-1-to-n.py) | _O(n^2)_ | _O(1)_      | Medium         ||
1023 | [Camelcase Matching](https://leetcode.com/problems/camelcase-matching/) | [C++](./C++/camelcase-matching.cpp) [Python](./Python/camelcase-matching.py) | _O(n * l)_ | _O(1)_      | Medium         ||
1061 | [Lexicographically Smallest Equivalent String](https://leetcode.com/problems/lexicographically-smallest-equivalent-string/) | [C++](./C++/lexicographically-smallest-equivalent-string.cpp) [Python](./Python/lexicographically-smallest-equivalent-string.py) | _O(n)_ | _O(n)_ |  Medium | 🔒 | Union Find
1056 | [Confusing Number](https://leetcode.com/problems/confusing-number/) | [C++](./C++/confusing-number.cpp) [Python](./Python/confusing-number.py) | _O(logn)_ | _O(logn)_ |  Easy | 🔒 |
1071 | [Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings/) | [C++](./C++/greatest-common-divisor-of-strings.cpp) [Python](./Python/greatest-common-divisor-of-strings.py) | _O(m + n)_ | _O(1)_      | Easy         ||
1078 | [Occurrences After Bigram](https://leetcode.com/problems/occurrences-after-bigram/) | [C++](./C++/occurrences-after-bigram.cpp) [Python](./Python/occurrences-after-bigram.py) | _O(n)_ | _O(1)_      | Easy         ||
1100 | [Find K-Length Substrings With No Repeated Characters](https://leetcode.com/problems/find-k-length-substrings-with-no-repeated-characters/) | [C++](./C++/find-k-length-substrings-with-no-repeated-characters.cpp) [Python](./Python/find-k-length-substrings-with-no-repeated-characters.py) | _O(n)_ | _O(k)_      | Medium         |🔒|
1108 | [Defanging an IP Address](https://leetcode.com/problems/defanging-an-ip-address/) | [C++](./C++/defanging-an-ip-address.cpp) [Python](./Python/defanging-an-ip-address.py) | _O(n)_ | _O(1)_      | Easy         ||
1119 | [Remove Vowels from a String](https://leetcode.com/problems/remove-vowels-from-a-string/) | [C++](./C++/remove-vowels-from-a-string.cpp) [Python](./Python/remove-vowels-from-a-string.py) | _O(n)_ | _O(1)_      | Easy         |🔒|
1147 | [Longest Chunked Palindrome Decomposition](https://leetcode.com/problems/longest-chunked-palindrome-decomposition/) | [C++](./C++/longest-chunked-palindrome-decomposition.cpp) [Python](./Python/longest-chunked-palindrome-decomposition.py) | _O(n)_ | _O(1)_ | Hard | | `Rabin-Karp Algorithm`
1177 | [Can Make Palindrome from Substring](https://leetcode.com/problems/can-make-palindrome-from-substring/) | [C++](./C++/can-make-palindrome-from-substring.cpp) [Python](./Python/can-make-palindrome-from-substring.py) | _O(m + n)_ | _O(n)_ | Medium | |
1178 | [Number of Valid Words for Each Puzzle](https://leetcode.com/problems/number-of-valid-words-for-each-puzzle/) | [C++](./C++/number-of-valid-words-for-each-puzzle.cpp) [Python](./Python/number-of-valid-words-for-each-puzzle.py) | _O(n * l + m * L)_ | _O(L!)_ | Hard | | Trie, Bit Manipulation
1189 | [Maximum Number of Balloons](https://leetcode.com/problems/maximum-number-of-balloons/) | [C++](./C++/maximum-number-of-balloons.cpp) [Python](./Python/maximum-number-of-balloons.py) | _O(n)_ | _O(1)_ | Easy | | Hash
1233 | [Remove Sub-Folders from the Filesystem](https://leetcode.com/problems/remove-sub-folders-from-the-filesystem/) | [C++](./C++/remove-sub-folders-from-the-filesystem.cpp) [Python](./Python/remove-sub-folders-from-the-filesystem.py) | _O(n)_ | _O(t)_ | Medium | | Trie
1271 | [Hexspeak](https://leetcode.com/problems/hexspeak/) | [C++](./C++/hexspeak.cpp) [Python](./Python/hexspeak.py) | _O(n)_ | _O(1)_ | Easy | |
1309 | [Decrypt String from Alphabet to Integer Mapping](https://leetcode.com/problems/decrypt-string-from-alphabet-to-integer-mapping/) | [C++](./C++/decrypt-string-from-alphabet-to-integer-mapping.cpp) [Python](./Python/decrypt-string-from-alphabet-to-integer-mapping.py) | _O(n)_ | _O(1)_ | Easy | |
1324 | [Print Words Vertically](https://leetcode.com/problems/print-words-vertically/) | [C++](./C++/print-words-vertically.cpp) [Python](./Python/print-words-vertically.py) | _O(n)_ | _O(n)_ | Medium | |
1328 | [Break a Palindrome](https://leetcode.com/problems/break-a-palindrome/) | [C++](./C++/break-a-palindrome.cpp) [Python](./Python/break-a-palindrome.py) | _O(n)_ | _O(1)_ | Medium | |
1332 | [Remove Palindromic Subsequences](https://leetcode.com/problems/remove-palindromic-subsequences/) | [C++](./C++/remove-palindromic-subsequences.cpp) [Python](./Python/remove-palindromic-subsequences.py) | _O(n)_ | _O(1)_ | Easy | |
1347 | [Minimum Number of Steps to Make Two Strings Anagram](https://leetcode.com/problems/minimum-number-of-steps-to-make-two-strings-anagram/) | [C++](./C++/minimum-number-of-steps-to-make-two-strings-anagram.cpp) [Python](./Python/minimum-number-of-steps-to-make-two-strings-anagram.py) | _O(n)_ | _O(1)_ | Medium | |
1370 | [Increasing Decreasing String](https://leetcode.com/problems/increasing-decreasing-string/) | [C++](./C++/increasing-decreasing-string.cpp) [Python](./Python/increasing-decreasing-string.py) | _O(n)_ | _O(1)_ | Easy | | Sort |
1371 | [Find the Longest Substring Containing Vowels in Even Counts](https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts/) | [C++](./C++/find-the-longest-substring-containing-vowels-in-even-counts.cpp) [Python](./Python/find-the-longest-substring-containing-vowels-in-even-counts.py) | _O(n)_ | _O(1)_ | Medium | |
1374 | [Generate a String With Characters That Have Odd Count](https://leetcode.com/problems/generate-a-string-with-characters-that-have-odd-counts/) | [C++](./C++/generate-a-string-with-characters-that-have-odd-counts.cpp) [Python](./Python/generate-a-string-with-characters-that-have-odd-counts.py) | _O(n)_ | _O(1)_ | Easy | |
1392 | [Longest Happy Prefix](https://leetcode.com/problems/longest-happy-prefix/) | [C++](./C++/longest-happy-prefix.cpp)  [Python](./Python/longest-happy-prefix.py) | _O(n)_ | _O(n)_ | Hard         || `KMP Algorithm`, `Rabin-Karp Algorithm` |
1408 | [String Matching in an Array](https://leetcode.com/problems/string-matching-in-an-array/)| [C++](./C++/string-matching-in-an-array.cpp) [Python](./Python/string-matching-in-an-array.py) | _O(n)_ | _O(t)_ | Easy || `KMP Algorithm`, `Aho-Corasick Automata`, Trie |
1410 | [HTML Entity Parser](https://leetcode.com/problems/html-entity-parser/)| [C++](./C++/html-entity-parser.cpp) [Python](./Python/html-entity-parser.py)| _O(n)_ | _O(t)_ | Medium || `Aho-Corasick Automata`, Trie |
1417 | [Reformat The String](https://leetcode.com/problems/reformat-the-string/)| [C++](./C++/reformat-the-string.cpp) [Python](./Python/reformat-the-string.py)| _O(n)_ | _O(1)_ | Easy |||
1422 | [Maximum Score After Splitting a String](https://leetcode.com/problems/maximum-score-after-splitting-a-string/)| [C++](./C++/maximum-score-after-splitting-a-string.cpp) [Python](./Python/maximum-score-after-splitting-a-string.py)| _O(n)_ | _O(1)_ | Easy |||
1432 | [Max Difference You Can Get From Changing an Integer](https://leetcode.com/problems/max-difference-you-can-get-from-changing-an-integer/)| [C++](./C++/max-difference-you-can-get-from-changing-an-integer.cpp) [Python](./Python/max-difference-you-can-get-from-changing-an-integer.py)| _O(logn)_ | _O(logn)_ | Medium |||
1436 | [Destination City](https://leetcode.com/problems/destination-city/)| [C++](./C++/destination-city.cpp) [Python](./Python/destination-city.py)| _O(n)_ | _O(n)_ | Easy |||
1446 | [Consecutive Characters](https://leetcode.com/problems/consecutive-characters/)| [C++](./C++/consecutive-characters.cpp) [Python](./Python/consecutive-characters.py)| _O(n)_ | _O(1)_ | Easy |||
1455 | [Check If a Word Occurs As a Prefix of Any Word in a Sentence](https://leetcode.com/problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence/) | [C++](./C++/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence.cpp) [Python](./Python/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence.py) | _O(n)_ | _O(n)_ | Easy || `KMP Algorithm` |
1461 | [Check If a String Contains All Binary Codes of Size K](https://leetcode.com/problems/check-if-a-string-contains-all-binary-codes-of-size-k/) | [C++](./C++/check-if-a-string-contains-all-binary-codes-of-size-k.cpp) [Python](./Python/check-if-a-string-contains-all-binary-codes-of-size-k.py) | _O(n * k)_ | _O(k * 2^k)_ | Medium || Bit Manipulation |
1496 | [Path Crossing](https://leetcode.com/problems/path-crossing/) | [C++](./C++/path-crossing.cpp) [Python](./Python/path-crossing.py) | _O(n)_ | _O(n)_ | Easy |||
1507 | [Reformat Date](https://leetcode.com/problems/reformat-date/) | [C++](./C++/reformat-date.cpp) [Python](./Python/reformat-date.py) | _O(n)_ | _O(1)_ | Easy |||
1528 | [Shuffle String](https://leetcode.com/problems/shuffle-string/) | [C++](./C++/shuffle-string.cpp) [Python](./Python/shuffle-string.py) | _O(n)_ | _O(1)_ | Easy |||
1529 | [Bulb Switcher IV](https://leetcode.com/problems/bulb-switcher-iv/) | [C++](./C++/bulb-switcher-iv.cpp) [Python](./Python/bulb-switcher-iv.py) | _O(n)_ | _O(1)_ | Medium |||
1540 | [Can Convert String in K Moves](https://leetcode.com/problems/can-convert-string-in-k-moves/) | [C++](./C++/can-convert-string-in-k-moves.cpp) [Python](./Python/can-convert-string-in-k-moves.py) | _O(n)_ | _O(1)_ | Medium |||
1542 | [Find Longest Awesome Substring](https://leetcode.com/problems/find-longest-awesome-substring/) | [C++](./C++/find-longest-awesome-substring.cpp) [Python](./Python/find-longest-awesome-substring.py) | _O(n)_ | _O(1)_ | Hard |||
1544 | [Make The String Great](https://leetcode.com/problems/make-the-string-great/) | [C++](./C++/make-the-string-great.cpp) [Python](./Python/make-the-string-great.py) | _O(n)_ | _O(1)_ | Easy |||
1545 | [Find Kth Bit in Nth Binary String](https://leetcode.com/problems/find-kth-bit-in-nth-binary-string/) | [C++](./C++/find-kth-bit-in-nth-binary-string.cpp) [Python](./Python/find-kth-bit-in-nth-binary-string.py) | _O(n)_ | _O(1)_ | Medium |||
1554 | [Strings Differ by One Character](https://leetcode.com/problems/strings-differ-by-one-character/) | [C++](./C++/strings-differ-by-one-character.cpp) [Python](./Python/strings-differ-by-one-character.py) | _O(n * m)_ | _O(n)_ | Medium || `Rabin-Karp Algorithm` |
1556 | [Thousand Separator](https://leetcode.com/problems/thousand-separator/) | [C++](./C++/thousand-separator.cpp) [Python](./Python/thousand-separator.py) | _O(n)_ | _O(1)_ | Easy |||
1573 | [Number of Ways to Split a String](https://leetcode.com/problems/number-of-ways-to-split-a-string/) | [C++](./C++/number-of-ways-to-split-a-string.cpp) [Python](./Python/number-of-ways-to-split-a-string.py) | _O(n)_ | _O(1)_ | Medium |||
1576 | [Replace All ?'s to Avoid Consecutive Repeating Characters](https://leetcode.com/problems/replace-all-s-to-avoid-consecutive-repeating-characters/) | [C++](./C++/replace-all-s-to-avoid-consecutive-repeating-characters.cpp) [Python](./Python/replace-all-s-to-avoid-consecutive-repeating-characters.py) | _O(n)_ | _O(1)_ | Easy |||
1592 | [Rearrange Spaces Between Words](https://leetcode.com/problems/rearrange-spaces-between-words/) | [C++](./C++/rearrange-spaces-between-words.cpp) [Python](./Python/rearrange-spaces-between-words.py) | _O(n)_ | _O(1)_ | Easy || Inplace |
1598 | [Crawler Log Folder](https://leetcode.com/problems/crawler-log-folder/) | [C++](./C++/crawler-log-folder.cpp) [Python](./Python/crawler-log-folder.py) | _O(n)_ | _O(1)_ | Easy |||
1614 | [Maximum Nesting Depth of the Parentheses](https://leetcode.com/problems/maximum-nesting-depth-of-the-parentheses/) | [C++](./C++/maximum-nesting-depth-of-the-parentheses.cpp) [Python](./Python/maximum-nesting-depth-of-the-parentheses.py) | _O(n)_ | _O(1)_ | Easy |||
1624 | [Largest Substring Between Two Equal Characters](https://leetcode.com/problems/largest-substring-between-two-equal-characters/) | [C++](./C++/largest-substring-between-two-equal-characters.cpp) [Python](./Python/largest-substring-between-two-equal-characters.py) | _O(n)_ | _O(1)_ | Easy |||
1638 | [Count Substrings That Differ by One Character](https://leetcode.com/problems/count-substrings-that-differ-by-one-character/) | [C++](./C++/count-substrings-that-differ-by-one-character.cpp) [Python](./Python/count-substrings-that-differ-by-one-character.py) | _O(m * n)_ | _O(1)_ | Medium | variant of [Count Unique Characters of All Substrings of a Given String](https://leetcode.com/problems/count-unique-characters-of-all-substrings-of-a-given-string/) | Tricky |
1662 | [Check If Two String Arrays are Equivalent](https://leetcode.com/problems/check-if-two-string-arrays-are-equivalent/) | [C++](./C++/check-if-two-string-arrays-are-equivalent.cpp) [Python](./Python/check-if-two-string-arrays-are-equivalent.py) | _O(n)_ | _O(1)_ | Easy |||
1668 | [Maximum Repeating Substring](https://leetcode.com/problems/maximum-repeating-substring/) | [C++](./C++/maximum-repeating-substring.cpp) [Python](./Python/maximum-repeating-substring.py) | _O(n)_ | _O(m)_ | Easy || `KMP Algorithm` |
1678 | [Goal Parser Interpretation](https://leetcode.com/problems/goal-parser-interpretation/) | [C++](./C++/goal-parser-interpretation.cpp) [Python](./Python/goal-parser-interpretation.py) | _O(n)_ | _O(1)_ | Easy |||
1684 | [Count the Number of Consistent Strings](https://leetcode.com/problems/count-the-number-of-consistent-strings/) | [C++](./C++/count-the-number-of-consistent-strings.cpp) [Python](./Python/count-the-number-of-consistent-strings.py) | _O(n)_ | _O(1)_ | Easy |||
1694 | [Reformat Phone Number](https://leetcode.com/problems/reformat-phone-number/) | [C++](./C++/reformat-phone-number.cpp) [Python](./Python/reformat-phone-number.py) | _O(n)_ | _O(1)_ | Easy || Inplace |
1698 | [Number of Distinct Substrings in a String](https://leetcode.com/problems/number-of-distinct-substrings-in-a-string/) | [C++](./C++/number-of-distinct-substrings-in-a-string.cpp) [Python](./Python/number-of-distinct-substrings-in-a-string.py) | _O(n^2)_ | _O(t)_ | Medium | 🔒 | Trie |
1704 | [Determine if String Halves Are Alike](https://leetcode.com/problems/determine-if-string-halves-are-alike/) | [C++](./C++/determine-if-string-halves-are-alike.cpp) [Python](./Python/determine-if-string-halves-are-alike.py) | _O(n)_ | _O(1)_ | Easy |||
1763 | [Longest Nice Substring](https://leetcode.com/problems/longest-nice-substring/) | [C++](./C++/longest-nice-substring.cpp) [Python](./Python/longest-nice-substring.py) | _O(n)_ | _O(n)_ | Easy |||
1768 | [Merge Strings Alternately](https://leetcode.com/problems/merge-strings-alternately/) | [C++](./C++/merge-strings-alternately.cpp) [Python](./Python/merge-strings-alternately.py) | _O(m + n)_ | _O(1)_ | Easy |||
1784 | [Check if Binary String Has at Most One Segment of Ones](https://leetcode.com/problems/check-if-binary-string-has-at-most-one-segment-of-ones/) | [C++](./C++/check-if-binary-string-has-at-most-one-segment-of-ones.cpp) [Python](./Python/check-if-binary-string-has-at-most-one-segment-of-ones.py) | _O(n)_ | _O(1)_ | Easy |||
1790 | [Check if One String Swap Can Make Strings Equal](https://leetcode.com/problems/check-if-one-string-swap-can-make-strings-equal/) | [C++](./C++/check-if-one-string-swap-can-make-strings-equal.cpp) [Python](./Python/check-if-one-string-swap-can-make-strings-equal.py) | _O(n)_ | _O(1)_ | Easy |||
1796 | [Second Largest Digit in a String](https://leetcode.com/problems/second-largest-digit-in-a-string/) | [C++](./C++/second-largest-digit-in-a-string.cpp) [Python](./Python/second-largest-digit-in-a-string.py) | _O(n)_ | _O(1)_ | Easy |||
1805 | [Number of Different Integers in a String](https://leetcode.com/problems/number-of-different-integers-in-a-string/) | [C++](./C++/number-of-different-integers-in-a-string.cpp) [Python](./Python/number-of-different-integers-in-a-string.py) | _O(n)_ | _O(n)_ | Easy |||
1813 | [Sentence Similarity III](https://leetcode.com/problems/sentence-similarity-iii/) | [C++](./C++/sentence-similarity-iii.cpp) [Python](./Python/sentence-similarity-iii.py) | _O(n)_ | _O(1)_ | Medium |||
1816 | [Truncate Sentence](https://leetcode.com/problems/truncate-sentence/) | [C++](./C++/truncate-sentence.cpp) [Python](./Python/truncate-sentence.py) | _O(n)_ | _O(1)_ | Easy |||
1832 | [Check if the Sentence Is Pangram](https://leetcode.com/problems/check-if-the-sentence-is-pangram/) | [C++](./C++/check-if-the-sentence-is-pangram.cpp) [Python](./Python/check-if-the-sentence-is-pangram.py) | _O(n)_ | _O(1)_ | Easy |||
1839 | [Longest Substring Of All Vowels in Order](https://leetcode.com/problems/longest-substring-of-all-vowels-in-order/) | [C++](./C++/longest-substring-of-all-vowels-in-order.cpp) [Python](./Python/longest-substring-of-all-vowels-in-order.py) | _O(n)_ | _O(1)_ | Medium |||
1844 | [Replace All Digits with Characters](https://leetcode.com/problems/replace-all-digits-with-characters/) | [C++](./C++/replace-all-digits-with-characters.cpp) [Python](./Python/replace-all-digits-with-characters.py) | _O(n)_ | _O(1)_ | Easy |||
1854 | [Maximum Population Year](https://leetcode.com/problems/maximum-population-year/) | [C++](./C++/maximum-population-year.cpp) [Python](./Python/maximum-population-year.py) | _O(n)_ | _O(1)_ | Easy || Line Sweep |
1858 | [Longest Word With All Prefixes](https://leetcode.com/problems/longest-word-with-all-prefixes/) | [C++](./C++/longest-word-with-all-prefixes.cpp) [Python](./Python/longest-word-with-all-prefixes.py) | _O(n)_ | _O(t)_ | Medium | 🔒 | Trie, DFS |
1876 | [Substrings of Size Three with Distinct Characters](https://leetcode.com/problems/substrings-of-size-three-with-distinct-characters/) | [C++](./C++/substrings-of-size-three-with-distinct-characters.cpp) [Python](./Python/substrings-of-size-three-with-distinct-characters.py) | _O(n)_ | _O(1)_ | Easy | |  |
1880 | [Check if Word Equals Summation of Two Words](https://leetcode.com/problems/check-if-word-equals-summation-of-two-words/) | [C++](./C++/check-if-word-equals-summation-of-two-words.cpp) [Python](./Python/check-if-word-equals-summation-of-two-words.py) | _O(n)_ | _O(1)_ | Easy | |  |
1903 | [Largest Odd Number in String](https://leetcode.com/problems/largest-odd-number-in-string/) | [C++](./C++/largest-odd-number-in-string.cpp) [Python](./Python/largest-odd-number-in-string.py) | _O(n)_ | _O(1)_ | Easy | |  |
1910 | [Remove All Occurrences of a Substring](https://leetcode.com/problems/remove-all-occurrences-of-a-substring/) | [C++](./C++/remove-all-occurrences-of-a-substring.cpp) [Python](./Python/remove-all-occurrences-of-a-substring.py) | _O(n + m)_ | _O(n + m)_ | Medium | | `KMP Algorithm` |
1933 | [Check if String Is Decomposable Into Value-Equal Substrings](https://leetcode.com/problems/check-if-string-is-decomposable-into-value-equal-substrings/) | [C++](./C++/check-if-string-is-decomposable-into-value-equal-substrings.cpp) [Python](./Python/check-if-string-is-decomposable-into-value-equal-substrings.py) | _O(n)_ | _O(1)_ |  Easy | 🔒 |
1935 | [Maximum Number of Words You Can Type](https://leetcode.com/problems/maximum-number-of-words-you-can-type/) | [C++](./C++/maximum-number-of-words-you-can-type.cpp) [Python](./Python/maximum-number-of-words-you-can-type.py) | _O(n)_ | _O(1)_ | Easy | |  |
1957 | [Delete Characters to Make Fancy String](https://leetcode.com/problems/delete-characters-to-make-fancy-string/) | [C++](./C++/delete-characters-to-make-fancy-string.cpp) [Python](./Python/delete-characters-to-make-fancy-string.py) | _O(n)_ | _O(1)_ | Easy || Inplace
1961 | [Check If String Is a Prefix of Array](https://leetcode.com/problems/check-if-string-is-a-prefix-of-array/) | [C++](./C++/check-if-string-is-a-prefix-of-array.cpp) [Python](./Python/check-if-string-is-a-prefix-of-array.py) | _O(n)_ | _O(1)_ | Easy ||
1963 | [Minimum Number of Swaps to Make the String Balanced](https://leetcode.com/problems/minimum-number-of-swaps-to-make-the-string-balanced/) | [C++](./C++/minimum-number-of-swaps-to-make-the-string-balanced.cpp) [Python](./Python/minimum-number-of-swaps-to-make-the-string-balanced.py) | _O(n)_ | _O(1)_ | Medium | variant of [Maximum Nesting Depth of the Parentheses](https://leetcode.com/problems/maximum-nesting-depth-of-the-parentheses/) ||
1967 | [Number of Strings That Appear as Substrings in Word](https://leetcode.com/problems/number-of-strings-that-appear-as-substrings-in-word/)| [C++](./C++/number-of-strings-that-appear-as-substrings-in-word.cpp) [Python](./Python/number-of-strings-that-appear-as-substrings-in-word.py) | _O(n * l + m)_ | _O(t)_ | Easy || `KMP Algorithm`, `Aho-Corasick Automata`, Trie |
1974 | [Minimum Time to Type Word Using Special Typewriter](https://leetcode.com/problems/minimum-time-to-type-word-using-special-typewriter/) | [C++](./C++/minimum-time-to-type-word-using-special-typewriter.cpp) [Python](./Python/minimum-time-to-type-word-using-special-typewriter.py) | _O(n)_ | _O(1)_ | Easy |||
2000 | [Reverse Prefix of Word](https://leetcode.com/problems/reverse-prefix-of-word/) | [C++](./C++/reverse-prefix-of-word.cpp) [Python](./Python/reverse-prefix-of-word.py) | _O(n)_ | _O(1)_ | Easy |||
2042 | [Check if Numbers Are Ascending in a Sentence](https://leetcode.com/problems/check-if-numbers-are-ascending-in-a-sentence/) | [C++](./C++/check-if-numbers-are-ascending-in-a-sentence.cpp) [Python](./Python/check-if-numbers-are-ascending-in-a-sentence.py) | _O(n)_ | _O(1)_ | Easy |||
2047 | [Number of Valid Words in a Sentence](https://leetcode.com/problems/number-of-valid-words-in-a-sentence/) | [C++](./C++/number-of-valid-words-in-a-sentence.cpp) [Python](./Python/number-of-valid-words-in-a-sentence.py) | _O(n)_ | _O(1)_ | Easy |||
2048 | [Next Greater Numerically Balanced Number](https://leetcode.com/problems/next-greater-numerically-balanced-number/) | [C++](./C++/next-greater-numerically-balanced-number.cpp) [Python](./Python/next-greater-numerically-balanced-number.py) | _O(1)_ | _O(1)_ | Medium || Permutations, Precompute, Binary Search |
2081 | [Sum of k-Mirror Numbers](https://leetcode.com/problems/sum-of-k-mirror-numbers/) | [C++](./C++/sum-of-k-mirror-numbers.cpp) [Python](./Python/sum-of-k-mirror-numbers.py) | _O(10^6)_ | _O(1)_ | Hard || String, Palindrome, Brute Force |
2103 | [Rings and Rods](https://leetcode.com/problems/rings-and-rods/) | [C++](./C++/rings-and-rods.cpp) [Python](./Python/rings-and-rods.py) | _O(n)_ | _O(1)_ | Easy || |
2108 | [Find First Palindromic String in the Array](https://leetcode.com/problems/find-first-palindromic-string-in-the-array/) | [C++](./C++/find-first-palindromic-string-in-the-array.cpp) [Python](./Python/find-first-palindromic-string-in-the-array.py) | _O(n)_ | _O(1)_ | Easy || |
2109 | [Adding Spaces to a String](https://leetcode.com/problems/adding-spaces-to-a-string/) | [C++](./C++/adding-spaces-to-a-string.cpp) [Python](./Python/adding-spaces-to-a-string.py) | _O(n)_ | _O(1)_ | Medium || Inplace |
2114 | [Maximum Number of Words Found in Sentences](https://leetcode.com/problems/maximum-number-of-words-found-in-sentences/) | [C++](./C++/maximum-number-of-words-found-in-sentences.cpp) [Python](./Python/maximum-number-of-words-found-in-sentences.py) | _O(n)_ | _O(1)_ | Easy |||
2116 | [Check if a Parentheses String Can Be Valid](https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/) | [C++](./C++/check-if-a-parentheses-string-can-be-valid.cpp) [Python](./Python/check-if-a-parentheses-string-can-be-valid.py) | _O(n)_ | _O(1)_ | Medium |||
2124 | [Check if All A's Appears Before All B's](https://leetcode.com/problems/check-if-all-as-appears-before-all-bs/) | [C++](./C++/check-if-all-as-appears-before-all-bs.cpp) [Python](./Python/check-if-all-as-appears-before-all-bs.py) | _O(n)_ | _O(1)_ | Easy |||
2129 | [Capitalize the Title](https://leetcode.com/problems/capitalize-the-title/) | [C++](./C++/capitalize-the-title.cpp) [Python](./Python/capitalize-the-title.py) | _O(n)_ | _O(1)_ | Easy |||
2131 | [Longest Palindrome by Concatenating Two Letter Words](https://leetcode.com/problems/longest-palindrome-by-concatenating-two-letter-words/) | [C++](./C++/longest-palindrome-by-concatenating-two-letter-words.cpp) [Python](./Python/longest-palindrome-by-concatenating-two-letter-words.py) | _O(n)_ | _O(n)_ | Medium |||
2135 | [Count Words Obtained After Adding a Letter](https://leetcode.com/problems/count-words-obtained-after-adding-a-letter/) | [C++](./C++/count-words-obtained-after-adding-a-letter.cpp) [Python](./Python/count-words-obtained-after-adding-a-letter.py) | _O(n)_ | _O(n)_ | Medium || Bitmask |
2138 | [Divide a String Into Groups of Size k](https://leetcode.com/problems/divide-a-string-into-groups-of-size-k/) | [C++](./C++/divide-a-string-into-groups-of-size-k.cpp) [Python](./Python/divide-a-string-into-groups-of-size-k.py) | _O(n)_ | _O(1)_ | Easy || |
2156 | [Find Substring With Given Hash Value](https://leetcode.com/problems/find-substring-with-given-hash-value/) | [C++](./C++/find-substring-with-given-hash-value.cpp) [Python](./Python/find-substring-with-given-hash-value.py) | _O(n)_ | _O(1)_ | Medium | | `Rabin-Karp Algorithm`, Rolling Hash
2157 | [Groups of Strings](https://leetcode.com/problems/groups-of-strings/) | [C++](./C++/groups-of-strings.cpp) [Python](./Python/groups-of-strings.py) | _O(26 * n)_ | _O(26 * n)_ | Hard | | Bitmasks, Union Find

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## Linked List
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1171 | [Remove Zero Sum Consecutive Nodes from Linked List](https://leetcode.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list/) | [C++](./C++/remove-zero-sum-consecutive-nodes-from-linked-list.cpp) [Python](./Python/remove-zero-sum-consecutive-nodes-from-linked-list.py) | _O(n)_ | _O(n)_ | Medium || OrderedDict, Hash
1180 | [Count Substrings with Only One Distinct Letter](https://leetcode.com/problems/count-substrings-with-only-one-distinct-letter/)| [C++](./C++/count-substrings-with-only-one-distinct-letter.cpp) [Python](./Python/count-substrings-with-only-one-distinct-letter.py) | _O(n)_       | _O(1)_         | Easy         | 🔒 ||
1181 | [Before and After Puzzle](https://leetcode.com/problems/before-and-after-puzzle/)| [C++](./C++/before-and-after-puzzle.cpp) [Python](./Python/before-and-after-puzzle.py) | _O(l * rlogr)_       | _O(l * (n + r))_         | Medium         | 🔒 | Hash |
1265 | [Print Immutable Linked List in Reverse](https://leetcode.com/problems/print-immutable-linked-list-in-reverse/) | [C++](./C++/print-immutable-linked-list-in-reverse.cpp) [Python](./Python/print-immutable-linked-list-in-reverse.py) | _O(n)_       | _O(sqrt(n))_         | Medium         | 🔒 ||
1290 | [Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/) | [C++](./C++/convert-binary-number-in-a-linked-list-to-integer.cpp) [Python](./Python/convert-binary-number-in-a-linked-list-to-integer.py) | _O(n)_       | _O(1)_         | Easy         |||
1474 | [Delete N Nodes After M Nodes of a Linked List](https://leetcode.com/problems/delete-n-nodes-after-m-nodes-of-a-linked-list/) | [C++](./C++/delete-n-nodes-after-m-nodes-of-a-linked-list.cpp) [Python](./Python/delete-n-nodes-after-m-nodes-of-a-linked-list.py) | _O(n)_       | _O(1)_         | Easy         | 🔒 ||
1634 | [Add Two Polynomials Represented as Linked Lists](https://leetcode.com/problems/add-two-polynomials-represented-as-linked-lists/)| [C++](./C++/add-two-polynomials-represented-as-linked-lists.cpp) [Python](./Python/add-two-polynomials-represented-as-linked-lists.py) | _O(m + n)_       | _O(1)_         | Medium         | 🔒 ||
1650 | [Lowest Common Ancestor of a Binary Tree III](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-iii/)| [C++](./C++/lowest-common-ancestor-of-a-binary-tree-iii.cpp)  [Python](./Python/lowest-common-ancestor-of-a-binary-tree-iii.py) | _O(h)_ | _O(1)_         | Medium           |🔒, variant of [Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists/) |
1669 | [Merge In Between Linked Lists](https://leetcode.com/problems/merge-in-between-linked-lists/)| [C++](./C++/merge-in-between-linked-lists.cpp)  [Python](./Python/merge-in-between-linked-lists.py) | _O(m + n)_ | _O(1)_         | Medium           ||
1721 | [Swapping Nodes in a Linked List](https://leetcode.com/problems/swapping-nodes-in-a-linked-list/)| [C++](./C++/swapping-nodes-in-a-linked-list.cpp)  [Python](./Python/swapping-nodes-in-a-linked-list.py) | _O(n)_ | _O(1)_         | Medium           ||
1836 | [Remove Duplicates From an Unsorted Linked List](https://leetcode.com/problems/remove-duplicates-from-an-unsorted-linked-list/)| [C++](./C++/remove-duplicates-from-an-unsorted-linked-list.cpp)  [Python](./Python/remove-duplicates-from-an-unsorted-linked-list.py) | _O(n)_ | _O(n)_         | Medium           | 🔒 |
2058 | [Find the Minimum and Maximum Number of Nodes Between Critical Points](https://leetcode.com/problems/find-the-minimum-and-maximum-number-of-nodes-between-critical-points/)| [C++](./C++/find-the-minimum-and-maximum-number-of-nodes-between-critical-points.cpp)  [Python](./Python/find-the-minimum-and-maximum-number-of-nodes-between-critical-points.py) | _O(n)_ | _O(1)_         | Medium           ||
2074 | [Reverse Nodes in Even Length Groups](https://leetcode.com/problems/reverse-nodes-in-even-length-groups/) | [C++](./C++/reverse-nodes-in-even-length-groups.cpp) [Python](./Python/reverse-nodes-in-even-length-groups.py) | _O(n)_  | _O(1)_         | Medium           | |
2095 | [Delete the Middle Node of a Linked List](https://leetcode.com/problems/delete-the-middle-node-of-a-linked-list/) | [C++](./C++/delete-the-middle-node-of-a-linked-list.cpp) [Python](./Python/delete-the-middle-node-of-a-linked-list.py) | _O(n)_  | _O(1)_         | Medium           | | Two Pointers
2130 | [Maximum Twin Sum of a Linked List](https://leetcode.com/problems/maximum-twin-sum-of-a-linked-list/) | [C++](./C++/maximum-twin-sum-of-a-linked-list.cpp) [Python](./Python/maximum-twin-sum-of-a-linked-list.py) | _O(n)_  | _O(1)_         | Medium           | | Two Pointers

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## Stack
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1003 | [Check If Word Is Valid After Substitutions](https://leetcode.com/problems/check-if-word-is-valid-after-substitutions/) | [C++](./C++/check-if-word-is-valid-after-substitutions.cpp) [Python](./Python/check-if-word-is-valid-after-substitutions.py) | _O(n)_  | _O(n)_         | Medium           ||
1019 | [Next Greater Node In Linked List](https://leetcode.com/problems/next-greater-node-in-linked-list/) | [C++](./C++/next-greater-node-in-linked-list.cpp) [Python](./Python/next-greater-node-in-linked-list.py) | _O(n)_  | _O(n)_         | Medium           || Mono Stack
1021 | [Remove Outermost Parentheses](https://leetcode.com/problems/remove-outermost-parentheses/) | [C++](./C++/remove-outermost-parentheses.cpp) [Python](./Python/remove-outermost-parentheses.py) | _O(n)_ | _O(1)_      | Easy         ||
1047 | [Remove All Adjacent Duplicates In String](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string/) | [C++](./C++/remove-all-adjacent-duplicates-in-string.cpp) [Python](./Python/remove-all-adjacent-duplicates-in-string.py) | _O(n)_ | _O(n)_      | Easy         ||
1063 | [Number of Valid Subarrays](https://leetcode.com/problems/number-of-valid-subarrays/)| [C++](./C++/number-of-valid-subarrays.cpp)  [Python](./Python/number-of-valid-subarrays.py)| _O(n)_ | _O(n)_         | Hard           | 🔒 | Mono Stack
1130 | [Minimum Cost Tree From Leaf Values](https://leetcode.com/problems/minimum-cost-tree-from-leaf-values/)| [C++](./C++/minimum-cost-tree-from-leaf-values.cpp)  [Python](./Python/minimum-cost-tree-from-leaf-values.py)| _O(n)_ | _O(n)_         | Medium           || Mono Stack
1190 | [Reverse Substrings Between Each Pair of Parentheses](https://leetcode.com/problems/reverse-substrings-between-each-pair-of-parentheses/)| [C++](./C++/reverse-substrings-between-each-pair-of-parentheses.cpp)  [Python](./Python/reverse-substrings-between-each-pair-of-parentheses.py)| _O(n)_ | _O(n)_         | Medium           ||
1209 | [Remove All Adjacent Duplicates in String II](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii/) | [C++](./C++/remove-all-adjacent-duplicates-in-string-ii.cpp) [Python](./Python/remove-all-adjacent-duplicates-in-string-ii.py) | _O(n)_ | _O(n)_      | Medium         ||
1441 | [Build an Array With Stack Operations](https://leetcode.com/problems/build-an-array-with-stack-operations/) | [C++](./C++/build-an-array-with-stack-operations.cpp) [Python](./Python/build-an-array-with-stack-operations.py) | _O(n)_ | _O(1)_      | Easy         ||
1541 | [Minimum Insertions to Balance a Parentheses String](https://leetcode.com/problems/minimum-insertions-to-balance-a-parentheses-string/) | [C++](./C++/minimum-insertions-to-balance-a-parentheses-string.cpp) [Python](./Python/minimum-insertions-to-balance-a-parentheses-string.py) | _O(n)_ | _O(1)_      | Medium         ||
1597 | [Build Binary Expression Tree From Infix Expression](https://leetcode.com/problems/build-binary-expression-tree-from-infix-expression/) | [C++](./C++/build-binary-expression-tree-from-infix-expression.cpp) [Python](./Python/build-binary-expression-tree-from-infix-expression.py) | _O(n)_  | _O(n)_         | Medium           | 🔒, variant of [Basic Calculator III](https://leetcode.com/problems/basic-calculator-iii/) |
1856 | [Maximum Subarray Min-Product](https://leetcode.com/problems/maximum-subarray-min-product/) | [C++](./C++/maximum-subarray-min-product.cpp) [Python](./Python/maximum-subarray-min-product.py) | _O(n)_ | _O(n)_ | Medium | variant of [Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/) | Mono Stack, Prefix Sum
1944 | [Number of Visible People in a Queue](https://leetcode.com/problems/number-of-visible-people-in-a-queue/) | [C++](./C++/number-of-visible-people-in-a-queue.cpp) [Python](./Python/number-of-visible-people-in-a-queue.py) | _O(n)_  | _O(n)_         | Hard           | variant of [Buildings With an Ocean View](https://leetcode.com/problems/buildings-with-an-ocean-view/) | Mono Stack
1950 | [Maximum of Minimum Values in All Subarrays](https://leetcode.com/problems/maximum-of-minimum-values-in-all-subarrays/) | [C++](./C++/maximum-of-minimum-values-in-all-subarrays.cpp) [Python](./Python/maximum-of-minimum-values-in-all-subarrays.py) | _O(n)_  | _O(n)_         | Medium           | 🔒 | Mono Stack
2104 | [Sum of Subarray Ranges](https://leetcode.com/problems/sum-of-subarray-ranges/) | [C++](./C++/sum-of-subarray-ranges.cpp) [Python](./Python/sum-of-subarray-ranges.py) | _O(n)_ | _O(n)_ | Medium | | Mono Stack

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## Queue
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1424 | [Diagonal Traverse II](https://leetcode.com/problems/diagonal-traverse-ii/)| [C++](./C++/diagonal-traverse-ii.cpp) [Python](./Python/diagonal-traverse-ii.py) | _O(m * n)_        | _O(m)_          | Medium           |||
1438 | [Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit](https://leetcode.com/problems/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit/)| [C++](./C++/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit.cpp) [Python](./Python/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit.py) | _O(n)_        | _O(n)_          | Hard           | | Mono Deque |
1499 | [Max Value of Equation](https://leetcode.com/problems/max-value-of-equation/)| [C++](./C++/max-value-of-equation.cpp) [Python](./Python/max-value-of-equation.py) | _O(n)_        | _O(n)_          | Hard           | | Mono Deque |
1696 | [Jump Game VI](https://leetcode.com/problems/jump-game-vi/) | [C++](./C++/jump-game-vi.cpp) [Python](./Python/jump-game-vi.py) | _O(n)_ | _O(k)_ | Medium | | Mono Deque, Sliding Window |

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## Binary Heap
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1046 | [Last Stone Weight](https://leetcode.com/problems/last-stone-weight/) | [C++](./C++/last-stone-weight.cpp) [Python](./Python/last-stone-weight.py) | _O(nlogn)_ | _O(n)_ | Easy |||
1057 | [Campus Bikes](https://leetcode.com/problems/campus-bikes/) | [C++](./C++/campus-bikes.cpp) [Python](./Python/campus-bikes.py) |  _O((w * b) * log(w * b))_ | _O(w * b)_   | Medium |🔒||
1383 | [Maximum Performance of a Team](https://leetcode.com/problems/maximum-performance-of-a-team/) | [C++](./C++/maximum-performance-of-a-team.cpp) [Python](./Python/maximum-performance-of-a-team.py) | _O(nlogn)_ | _O(n)_ | Hard | variant of [Minimum Cost to Hire K Workers](https://leetcode.com/problems/minimum-cost-to-hire-k-workers/) | Sort |
1439 | [Find the Kth Smallest Sum of a Matrix With Sorted Rows](https://leetcode.com/problems/find-the-kth-smallest-sum-of-a-matrix-with-sorted-rows/) | [C++](./C++/find-the-kth-smallest-sum-of-a-matrix-with-sorted-rows.cpp) [Python](./Python/find-the-kth-smallest-sum-of-a-matrix-with-sorted-rows.py) | _O(m * klogk)_ | _O(k)_ | Hard || Binary Search |
1606 | [Find Servers That Handled Most Number of Requests](https://leetcode.com/problems/find-servers-that-handled-most-number-of-requests/) | [C++](./C++/find-servers-that-handled-most-number-of-requests.cpp) [Python](./Python/find-servers-that-handled-most-number-of-requests.py) | _O(nlogk)_ | _O(k)_ | Hard | | Sorted List |
1642 | [Furthest Building You Can Reach](https://leetcode.com/problems/furthest-building-you-can-reach/) | [C++](./C++/furthest-building-you-can-reach.cpp) [Python](./Python/furthest-building-you-can-reach.py) | _O(nlogk)_ | _O(k)_ | Medium | | |
1675 | [Minimize Deviation in Array](https://leetcode.com/problems/minimize-deviation-in-array/) | [C++](./C++/minimize-deviation-in-array.cpp) [Python](./Python/minimize-deviation-in-array.py) | _O((n * log(max_num)) * logn)_ | _O(n)_ | Hard | | |
1792 | [Maximum Average Pass Ratio](https://leetcode.com/problems/maximum-average-pass-ratio/) | [C++](./C++/maximum-average-pass-ratio.cpp) [Python](./Python/maximum-average-pass-ratio.py) | _O(n + mlogn)_ | _O(n)_ | Medium | | |
1882 | [Process Tasks Using Servers](https://leetcode.com/problems/process-tasks-using-servers/) | [C++](./C++/process-tasks-using-servers.cpp) [Python](./Python/process-tasks-using-servers.py) | _O(n + mlogn)_ | _O(n)_ | Medium | | |
1962 | [Remove Stones to Minimize the Total](https://leetcode.com/problems/remove-stones-to-minimize-the-total/) | [C++](./C++/remove-stones-to-minimize-the-total.cpp) [Python](./Python/remove-stones-to-minimize-the-total.py) | _O(klogn)_ | _O(1)_ | Medium | | |
2054 | [Two Best Non-Overlapping Events](https://leetcode.com/problems/two-best-non-overlapping-events/) | [C++](./C++/two-best-non-overlapping-events.cpp) [Python](./Python/two-best-non-overlapping-events.py) | _O(nlogn)_ | _O(n)_ | Medium | | Line Sweep, Heap |

<br/>
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    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Tree
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1008 | [Construct Binary Search Tree from Preorder Traversal](https://leetcode.com/problems/construct-binary-search-tree-from-preorder-traversal/)| [C++](./C++/construct-binary-search-tree-from-preorder-traversal.cpp) [Python](./Python/construct-binary-search-tree-from-preorder-traversal.py)| _O(n)_ | _O(h)_ | Medium |||
1022 | [Sum of Root To Leaf Binary Numbers](https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/)| [C++](./C++/sum-of-root-to-leaf-binary-numbers.cpp) [Python](./Python/sum-of-root-to-leaf-binary-numbers.py)| _O(n)_ | _O(h)_ | Easy |||
1026 | [Maximum Difference Between Node and Ancestor](https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/)| [C++](./C++/maximum-difference-between-node-and-ancestor.cpp) [Python](./Python/maximum-difference-between-node-and-ancestor.py)| _O(n)_ | _O(h)_ | Medium || DFS |
1028 | [Recover a Tree From Preorder Traversal](https://leetcode.com/problems/recover-a-tree-from-preorder-traversal/)| [C++](./C++/recover-a-tree-from-preorder-traversal.cpp) [Python](./Python/recover-a-tree-from-preorder-traversal.py)| _O(n)_ | _O(h)_ | Hard || DFS |
1032 | [Stream of Characters](https://leetcode.com/problems/stream-of-characters/)| [C++](./C++/stream-of-characters.cpp) [C++](./C++/stream-of-characters2.cpp) [Python](./Python/stream-of-characters.py) [Python](./Python/stream-of-characters2.py) | ctor: _O(n)_ <br> query: _O(m)_ | _O(t)_ | Hard || `Aho-Corasick Automata`, Trie |
1038 | [Binary Search Tree to Greater Sum Tree](https://leetcode.com/problems/binary-search-tree-to-greater-sum-tree/)| [C++](./C++/binary-search-tree-to-greater-sum-tree.cpp) [Python](./Python/binary-search-tree-to-greater-sum-tree.py)| _O(n)_ | _O(h)_ | Medium || DFS |
1065 | [Index Pairs of a String](https://leetcode.com/problems/index-pairs-of-a-string/)| [C++](./C++/index-pairs-of-a-string.cpp)  [Python](./Python/index-pairs-of-a-string.py) | _O(n + m + z)_ | _O(t)_ | Easy |🔒| `Aho-Corasick Automata`, Trie |
1080 | [Insufficient Nodes in Root to Leaf Paths](https://leetcode.com/problems/insufficient-nodes-in-root-to-leaf-paths/)| [C++](./C++/insufficient-nodes-in-root-to-leaf-paths.cpp) [Python](./Python/insufficient-nodes-in-root-to-leaf-paths.py)| _O(n)_ | _O(h)_ | Medium || DFS |
1104 | [Path In Zigzag Labelled Binary Tree](https://leetcode.com/problems/path-in-zigzag-labelled-binary-tree/)| [C++](./C++/path-in-zigzag-labelled-binary-tree.cpp) [Python](./Python/path-in-zigzag-labelled-binary-tree.py)| _O(logn)_ | _O(logn)_ | Easy || Math |
1120 | [Maximum Average Subtree](https://leetcode.com/problems/maximum-average-subtree/)| [C++](./C++/maximum-average-subtree.cpp)  [Python](./Python/maximum-average-subtree.py) | _O(n)_ | _O(h)_ | Easy |🔒| DFS |
1123 | [Lowest Common Ancestor of Deepest Leaves](https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves/)| [C++](./C++/lowest-common-ancestor-of-deepest-leaves.cpp)  [Python](./Python/lowest-common-ancestor-of-deepest-leaves.py) | _O(n)_ | _O(h)_ | Medium || DFS |
1145 | [Binary Tree Coloring Game](https://leetcode.com/problems/binary-tree-coloring-game/)| [C++](./C++/binary-tree-coloring-game.cpp)  [Python](./Python/binary-tree-coloring-game.py) | _O(n)_ | _O(h)_ | Medium || DFS |
1257 | [Smallest Common Region](https://leetcode.com/problems/smallest-common-region/)| [C++](./C++/smallest-common-region.cpp)  [Python](./Python/smallest-common-region.py) | _O(m * n)_ | _O(n)_ | Medium |||
1261 | [Find Elements in a Contaminated Binary Tree](https://leetcode.com/problems/find-elements-in-a-contaminated-binary-tree/)| [C++](./C++/find-elements-in-a-contaminated-binary-tree.cpp)  [Python](./Python/find-elements-in-a-contaminated-binary-tree.py) | _O(n)_ | _O(h)_ | Medium || DFS|
1325 | [Delete Leaves With a Given Value](https://leetcode.com/problems/delete-leaves-with-a-given-value/)| [C++](./C++/delete-leaves-with-a-given-value.cpp)  [Python](./Python/delete-leaves-with-a-given-value.py) | _O(n)_ | _O(h)_ | Medium || DFS|
1339 | [Maximum Product of Splitted Binary Tree](https://leetcode.com/problems/maximum-product-of-splitted-binary-tree/)| [C++](./C++/maximum-product-of-splitted-binary-tree.cpp)  [Python](./Python/maximum-product-of-splitted-binary-tree.py) | _O(n)_ | _O(h)_ | Medium || DFS|
1409 | [Queries on a Permutation With Key](https://leetcode.com/problems/queries-on-a-permutation-with-key/) | [C++](./C++/queries-on-a-permutation-with-key.cpp) [Python](./Python/queries-on-a-permutation-with-key.py) | _O(nlogn)_ | _O(n)_ | Medium | | BIT, Fenwick Tree
1430 | [Check If a String Is a Valid Sequence from Root to Leaves Path in a Binary Tree](https://leetcode.com/problems/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree/)| [C++](./C++/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree.cpp) [Python](./Python/check-if-a-string-is-a-valid-sequence-from-root-to-leaves-path-in-a-binary-tree.py) | _O(n)_ | _O(h)_ | Medium | 🔒 |  BFS, DFS, Stack
1443 | [Minimum Time to Collect All Apples in a Tree](https://leetcode.com/problems/minimum-time-to-collect-all-apples-in-a-tree/) | [C++](./C++/minimum-time-to-collect-all-apples-in-a-tree.cpp) [Python](./Python/minimum-time-to-collect-all-apples-in-a-tree.py) | _O(n)_          | _O(n)_          | Medium           || DFS, Stack |
1448 | [Count Good Nodes in Binary Tree](https://leetcode.com/problems/count-good-nodes-in-binary-tree/)| [C++](./C++/count-good-nodes-in-binary-tree.cpp) [Python](./Python/count-good-nodes-in-binary-tree.py) | _O(n)_ | _O(h)_ | Medium | | DFS, Stack
1457 | [Pseudo-Palindromic Paths in a Binary Tree](https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree/)| [C++](./C++/pseudo-palindromic-paths-in-a-binary-tree.cpp) [Python](./Python/pseudo-palindromic-paths-in-a-binary-tree.py) | _O(n)_ | _O(h)_ | Medium | | DFS, Stack
1469 | [Find All The Lonely Nodes](https://leetcode.com/problems/find-all-the-lonely-nodes/)| [C++](./C++/find-all-the-lonely-nodes.cpp) [Python](./Python/find-all-the-lonely-nodes.py) | _O(n)_ | _O(h)_ | Easy | 🔒 | DFS, Stack
1490 | [Clone N-ary Tree](https://leetcode.com/problems/clone-n-ary-tree/) | [C++](./C++/clone-n-ary-tree.cpp) [Python](./Python/clone-n-ary-tree.py) | _O(n)_          | _O(h)_          | Medium           |🔒| DFS, Stack |
1505 | [Minimum Possible Integer After at Most K Adjacent Swaps On Digits](https://leetcode.com/problems/minimum-possible-integer-after-at-most-k-adjacent-swaps-on-digits/) | [C++](./C++/minimum-possible-integer-after-at-most-k-adjacent-swaps-on-digits.cpp) [Python](./Python/minimum-possible-integer-after-at-most-k-adjacent-swaps-on-digits.py) | _O(nlogn)_ | _O(n)_ | Hard | | BIT, Fenwick Tree
1506 | [Find Root of N-Ary Tree](https://leetcode.com/problems/find-root-of-n-ary-tree/)| [C++](./C++/find-root-of-n-ary-tree.cpp) [Python](./Python/find-root-of-n-ary-tree.py) | _O(n)_ | _O(1)_ | Medium | 🔒 | Bit Manipulation
1516 | [Move Sub-Tree of N-Ary Tree](https://leetcode.com/problems/move-sub-tree-of-n-ary-tree/)| [C++](./C++/move-sub-tree-of-n-ary-tree.cpp) [Python](./Python/move-sub-tree-of-n-ary-tree.py) | _O(n)_ | _O(h)_ | Hard | 🔒 | DFS, Stack
1519 | [Number of Nodes in the Sub-Tree With the Same Label](https://leetcode.com/problems/number-of-nodes-in-the-sub-tree-with-the-same-label/) | [C++](./C++/number-of-nodes-in-the-sub-tree-with-the-same-label.cpp) [Python](./Python/number-of-nodes-in-the-sub-tree-with-the-same-label.py) | _O(n)_          | _O(h)_          | Medium           || DFS, Stack |
1522 | [Diameter of N-Ary Tree](https://leetcode.com/problems/diameter-of-n-ary-tree/) | [C++](./C++/diameter-of-n-ary-tree.cpp) [Python](./Python/diameter-of-n-ary-tree.py) | _O(n)_          | _O(h)_          | Medium           |🔒| DFS, Stack |
1530 | [Number of Good Leaf Nodes Pairs](https://leetcode.com/problems/number-of-good-leaf-nodes-pairs/)| [C++](./C++/number-of-good-leaf-nodes-pairs.cpp) [Python](./Python/number-of-good-leaf-nodes-pairs.py) | _O(n)_ | _O(h)_ | Medium | | DFS, Stack
1612 | [Check If Two Expression Trees are Equivalent](https://leetcode.com/problems/check-if-two-expression-trees-are-equivalent/)  | [C++](./C++/check-if-two-expression-trees-are-equivalent.cpp) [Python](./Python/check-if-two-expression-trees-are-equivalent.py) | _O(n)_| _O(1)_| Medium           |🔒| `Morris Traversal`, Inorder Traversal, Stack, Hash Table | 
1649 | [Create Sorted Array through Instructions](https://leetcode.com/problems/create-sorted-array-through-instructions/)| [C++](./C++/create-sorted-array-through-instructions.cpp) [Python](./Python/create-sorted-array-through-instructions.py)| _O(nlogn)_ | _O(n)_ | Hard | variant of [Count of Smaller Numbers After Self](https://leetcode.com/problems/count-of-smaller-numbers-after-self/) | BIT, Fenwick Tree, Merge Sort |
1666 | [Change the Root of a Binary Tree](https://leetcode.com/problems/change-the-root-of-a-binary-tree/)  | [C++](./C++/change-the-root-of-a-binary-tree.cpp) [Python](./Python/change-the-root-of-a-binary-tree.py) | _O(h)_| _O(1)_| Medium           |🔒| | 
1834 | [Single-Threaded CPU](https://leetcode.com/problems/single-threaded-cpu/)  | [C++](./C++/single-threaded-cpu.cpp) [Python](./Python/single-threaded-cpu.py) | _O(nlogn)_| _O(n)_| Medium           | | | 
1938 | [Maximum Genetic Difference Query](https://leetcode.com/problems/maximum-genetic-difference-query/) | [C++](./C++/maximum-genetic-difference-query.cpp) [Python](./Python/maximum-genetic-difference-query.py) | _O(nlogk + mlogk)_ | _O(n + logk)_ | Hard | variant of [Maximum XOR With an Element From Array](https://leetcode.com/problems/maximum-xor-with-an-element-from-array/) | DFS, Greedy, Trie
1948 | [Delete Duplicate Folders in System](https://leetcode.com/problems/delete-duplicate-folders-in-system/) |[C++](./C++/delete-duplicate-folders-in-system.cpp)  [Python](./Python/delete-duplicate-folders-in-system.py) | _O(n * m * l + tlogt + l * t)_ | _O(l * t)_ | Hard         | variant of [Find Duplicate Subtrees](https://leetcode.com/problems/find-duplicate-subtrees/) | Trie, DFS, Hash
2003 | [Smallest Missing Genetic Value in Each Subtree](https://leetcode.com/problems/smallest-missing-genetic-value-in-each-subtree/) |[C++](./C++/smallest-missing-genetic-value-in-each-subtree.cpp)  [Python](./Python/smallest-missing-genetic-value-in-each-subtree.py) | _O(n)_ | _O(n)_ | Hard         | | DFS, Stack
2096 | [Step-By-Step Directions From a Binary Tree Node to Another](https://leetcode.com/problems/step-by-step-directions-from-a-binary-tree-node-to-another/) |[C++](./C++/step-by-step-directions-from-a-binary-tree-node-to-another.cpp)  [Python](./Python/step-by-step-directions-from-a-binary-tree-node-to-another.py) | _O(n)_ | _O(h)_ | Medium         | | DFS, Stack

<br/>
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    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Hash Table
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1001 | [Grid Illumination](https://leetcode.com/problems/grid-illumination/) |[C++](./C++/grid-illumination.cpp)  [Python](./Python/grid-illumination.py) | _O(l + q)_ | _O(l)_ | Hard         ||
1124 | [Longest Well-Performing Interval](https://leetcode.com/problems/longest-well-performing-interval/) |[C++](./C++/longest-well-performing-interval.cpp)  [Python](./Python/longest-well-performing-interval.py) | _O(n)_ | _O(n)_ | Medium         ||
1133 | [Largest Unique Number](https://leetcode.com/problems/largest-unique-number/) | [C++](./C++/largest-unique-number.cpp) [Python](./Python/largest-unique-number.py) | _O(n)_| _O(n)_| Easy |🔒| Hash |
1152 | [Analyze User Website Visit Pattern](https://leetcode.com/problems/analyze-user-website-visit-pattern/) | [C++](./C++/analyze-user-website-visit-pattern.cpp) [Python](./Python/analyze-user-website-visit-pattern.py) | _O(n^3)_| _O(n^3)_| Medium |🔒| Hash |
1153 | [String Transforms Into Another String](https://leetcode.com/problems/string-transforms-into-another-string/) | [C++](./C++/string-transforms-into-another-string.cpp) [Python](./Python/string-transforms-into-another-string.py) | _O(n)_| _O(1)_| Hard |🔒| Hash |
1160 | [Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters/) |[C++](./C++/find-words-that-can-be-formed-by-characters.cpp)  [Python](./Python/find-words-that-can-be-formed-by-characters.py) | _O(m * n)_ | _O(1)_ | Easy         ||
1165 | [Single-Row Keyboard](https://leetcode.com/problems/single-row-keyboard/) | [C++](./C++/single-row-keyboard.cpp) [Python](./Python/single-row-keyboard.py)  | _O(n)_ |  _O(1)_ | Easy         |🔒||
1198 | [Find Smallest Common Element in All Rows](https://leetcode.com/problems/find-smallest-common-element-in-all-rows/) | [C++](./C++/find-smallest-common-element-in-all-rows.cpp) [Python](./Python/find-smallest-common-element-in-all-rows.py)  | _O(m * n)_ |  _O(n)_ | Medium         |🔒||
1207 | [Unique Number of Occurrences](https://leetcode.com/problems/unique-number-of-occurrences/) | [C++](./C++/unique-number-of-occurrences.cpp) [Python](./Python/unique-number-of-occurrences.py)  | _O(n)_ |  _O(n)_ | Easy         |||
1224 | [Maximum Equal Frequency](https://leetcode.com/problems/maximum-equal-frequency/) | [C++](./C++/maximum-equal-frequency.cpp) [Python](./Python/maximum-equal-frequency.py)  | _O(n)_ |  _O(n)_ | Hard         |||
1418 | [Display Table of Food Orders in a Restaurant](https://leetcode.com/problems/display-table-of-food-orders-in-a-restaurant/) | [C++](./C++/display-table-of-food-orders-in-a-restaurant.cpp) [Python](./Python/display-table-of-food-orders-in-a-restaurant.py)  | _O(n + tlogt + flogf)_ |  _O(n)_ | Medium         |||
1452 | [People Whose List of Favorite Companies Is Not a Subset of Another List](https://leetcode.com/problems/people-whose-list-of-favorite-companies-is-not-a-subset-of-another-list/) | [C++](./C++/people-whose-list-of-favorite-companies-is-not-a-subset-of-another-list.cpp) [Python](./Python/people-whose-list-of-favorite-companies-is-not-a-subset-of-another-list.py) | _O(n * m * l + n^2 * m)_   | _O(n * m * l)_        | Medium         ||
1487 | [Making File Names Unique](https://leetcode.com/problems/making-file-names-unique/) | [C++](./C++/making-file-names-unique.cpp) [Python](./Python/making-file-names-unique.py) | _O(n)_   | _O(n)_        | Medium         ||
1577 | [Number of Ways Where Square of Number Is Equal to Product of Two Numbers](https://leetcode.com/problems/number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers/) | [C++](./C++/number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers.cpp) [Python](./Python/number-of-ways-where-square-of-number-is-equal-to-product-of-two-numbers.py) | _O(m * n)_   | _O(m + n)_        | Medium         ||
1590 | [Make Sum Divisible by P](https://leetcode.com/problems/make-sum-divisible-by-p/) |[C++](./C++/make-sum-divisible-by-p.cpp)  [Python](./Python/make-sum-divisible-by-p.py) | _O(n)_ | _O(p)_ | Medium         | variant of [Subarray Sums Divisible by K](https://leetcode.com/problems/subarray-sums-divisible-by-k/) |
1640 | [Check Array Formation Through Concatenation](https://leetcode.com/problems/check-array-formation-through-concatenation/) | [C++](./C++/check-array-formation-through-concatenation.cpp) [Python](./Python/check-array-formation-through-concatenation.py) | _O(n)_   | _O(n)_        | Easy         ||
1657 | [Determine if Two Strings Are Close](https://leetcode.com/problems/determine-if-two-strings-are-close/) | [C++](./C++/determine-if-two-strings-are-close.cpp) [Python](./Python/determine-if-two-strings-are-close.py) | _O(n)_   | _O(1)_        | Medium         ||
1679 | [Max Number of K-Sum Pairs](https://leetcode.com/problems/max-number-of-k-sum-pairs/) | [C++](./C++/max-number-of-k-sum-pairs.cpp) [Python](./Python/max-number-of-k-sum-pairs.py) | _O(n)_   | _O(n)_        | Medium         ||
1711 | [Count Good Meals](https://leetcode.com/problems/count-good-meals/)      | [C++](./C++/count-good-meals.cpp) [Python](./Python/count-good-meals.py)      | _O(n)_         | _O(1)_          | Medium         ||
1748 | [Sum of Unique Elements](https://leetcode.com/problems/sum-of-unique-elements/)      | [C++](./C++/sum-of-unique-elements.cpp) [Python](./Python/sum-of-unique-elements.py)      | _O(n)_         | _O(n)_          | Easy         ||
1781 | [Sum of Beauty of All Substrings](https://leetcode.com/problems/sum-of-beauty-of-all-substrings/)      | [C++](./C++/sum-of-beauty-of-all-substrings.cpp) [Python](./Python/sum-of-beauty-of-all-substrings.py)      | _O(n^2)_         | _O(1)_          | Medium         ||
1807 | [Evaluate the Bracket Pairs of a String](https://leetcode.com/problems/evaluate-the-bracket-pairs-of-a-string/)      | [C++](./C++/evaluate-the-bracket-pairs-of-a-string.cpp) [Python](./Python/evaluate-the-bracket-pairs-of-a-string.py)      | _O(n + m)_         | _O(n + m)_          | Medium         ||
1814 | [Count Nice Pairs in an Array](https://leetcode.com/problems/count-nice-pairs-in-an-array/)      | [C++](./C++/count-nice-pairs-in-an-array.cpp) [Python](./Python/count-nice-pairs-in-an-array.py)      | _O(nlogm)_         | _O(n)_          | Medium         ||
1817 | [Finding the Users Active Minutes](https://leetcode.com/problems/finding-the-users-active-minutes/)      | [C++](./C++/finding-the-users-active-minutes.cpp) [Python](./Python/finding-the-users-active-minutes.py)      | _O(n)_         | _O(n)_          | Medium         ||
1915 | [Number of Wonderful Substrings](https://leetcode.com/problems/number-of-wonderful-substrings/)      | [C++](./C++/number-of-wonderful-substrings.cpp) [Python](./Python/number-of-wonderful-substrings.py)      | _O(n)_         | _O(1)_          | Medium         ||
1923 | [Longest Common Subpath](https://leetcode.com/problems/longest-common-subpath/)      | [C++](./C++/longest-common-subpath.cpp) [Python](./Python/longest-common-subpath.py)      | _O(m * nlogn)_         | _O(n)_          | Hard         || Binary Search, `Rabin-Karp Algorithm`
1925 | [Count Square Sum Triples](https://leetcode.com/problems/count-square-sum-triples/)      | [C++](./C++/count-square-sum-triples.cpp) [Python](./Python/count-square-sum-triples.py)      | _O(n^2)_         | _O(n)_          | Easy         ||
1930 | [Unique Length-3 Palindromic Subsequences](https://leetcode.com/problems/unique-length-3-palindromic-subsequences/)      | [C++](./C++/unique-length-3-palindromic-subsequences.cpp) [Python](./Python/unique-length-3-palindromic-subsequences.py)      | _O(n)_         | _O(1)_          | Medium         ||
1941 | [Check if All Characters Have Equal Number of Occurrences](https://leetcode.com/problems/check-if-all-characters-have-equal-number-of-occurrences/)      | [C++](./C++/check-if-all-characters-have-equal-number-of-occurrences.cpp) [Python](./Python/check-if-all-characters-have-equal-number-of-occurrences.py)      | _O(n)_         | _O(1)_          | Easy         ||
1995 | [Count Special Quadruplets](https://leetcode.com/problems/count-special-quadruplets/)         | [C++](./C++/count-special-quadruplets.cpp) [Python](./Python/count-special-quadruplets.py)        | _O(n^3)_    | _O(n)_    | Easy         | variant of [4 Sum](https://leetcode.com/problems/4sum/) |
2006 | [Count Number of Pairs With Absolute Difference K](https://leetcode.com/problems/count-number-of-pairs-with-absolute-difference-k/)      | [C++](./C++/count-number-of-pairs-with-absolute-difference-k.cpp) [Python](./Python/count-number-of-pairs-with-absolute-difference-k.py)      | _O(n)_         | _O(n)_          | Easy         | variant of [Two Sum](https://leetcode.com/problems/two-sum/) |
2023 | [Number of Pairs of Strings With Concatenation Equal to Target](https://leetcode.com/problems/number-of-pairs-of-strings-with-concatenation-equal-to-target/)      | [C++](./C++/number-of-pairs-of-strings-with-concatenation-equal-to-target.cpp) [Python](./Python/number-of-pairs-of-strings-with-concatenation-equal-to-target.py)      | _O(n * l)_         | _O(n)_          | Medium         | variant of [Two Sum](https://leetcode.com/problems/two-sum/) |
2025 | [Maximum Number of Ways to Partition an Array](https://leetcode.com/problems/maximum-number-of-ways-to-partition-an-array/) | [C++](./C++/maximum-number-of-ways-to-partition-an-array.cpp) [Python](./Python/maximum-number-of-ways-to-partition-an-array.py) | _O(n)_ | _O(n)_ | Hard || Prefix Sum
2032 | [Two Out of Three](https://leetcode.com/problems/two-out-of-three/) | [C++](./C++/two-out-of-three.cpp) [Python](./Python/two-out-of-three.py) | _O(n)_ | _O(min(n, r))_ | Easy || Counting
2053 | [Kth Distinct String in an Array](https://leetcode.com/problems/kth-distinct-string-in-an-array/) | [C++](./C++/kth-distinct-string-in-an-array.cpp) [Python](./Python/kth-distinct-string-in-an-array.py) | _O(n)_ | _O(n)_ | Easy || 
2068 | [Check Whether Two Strings are Almost Equivalent](https://leetcode.com/problems/check-whether-two-strings-are-almost-equivalent/) | [C++](./C++/check-whether-two-strings-are-almost-equivalent.cpp) [Python](./Python/check-whether-two-strings-are-almost-equivalent.py) | _O(n)_ | _O(1)_ | Easy || 
2085 | [Count Common Words With One Occurrence](https://leetcode.com/problems/count-common-words-with-one-occurrence/) | [C++](./C++/count-common-words-with-one-occurrence.cpp) [Python](./Python/count-common-words-with-one-occurrence.py) | _O(m + n)_ | _O(m + n)_ | Easy || 
2120 | [Execution of All Suffix Instructions Staying in a Grid](https://leetcode.com/problems/execution-of-all-suffix-instructions-staying-in-a-grid/) | [C++](./C++/execution-of-all-suffix-instructions-staying-in-a-grid.cpp) [Python](./Python/execution-of-all-suffix-instructions-staying-in-a-grid.py) | _O(m)_ | _O(m)_ | Medium || 
2150 | [Find All Lonely Numbers in the Array](https://leetcode.com/problems/find-all-lonely-numbers-in-the-array/) | [C++](./C++/find-all-lonely-numbers-in-the-array.cpp) [Python](./Python/find-all-lonely-numbers-in-the-array.py) | _O(n)_ | _O(n)_ | Medium || 
2154 | [Keep Multiplying Found Values by Two](https://leetcode.com/problems/keep-multiplying-found-values-by-two/) | [C++](./C++/keep-multiplying-found-values-by-two.cpp) [Python](./Python/keep-multiplying-found-values-by-two.py) | _O(n)_ | _O(n)_ | Easy || 

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Math
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1006 | [Clumsy Factorial](https://leetcode.com/problems/clumsy-factorial/) | [C++](./C++/clumsy-factorial.cpp) [Python](./Python/clumsy-factorial.py) | _O(1)_ | _O(1)_      | Medium         ||
1009 | [Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/) | [C++](./C++/complement-of-base-10-integer.cpp) [Python](./Python/complement-of-base-10-integer.py) | _O(logn)_ | _O(1)_      | Easy         ||
1012 | [Numbers With Repeated Digits](https://leetcode.com/problems/numbers-with-repeated-digits/) | [C++](./C++/numbers-with-repeated-digits.cpp) [Python](./Python/numbers-with-repeated-digits.py) | _O(logn)_ | _O(logn)_      | Hard         ||
1015 | [Smallest Integer Divisible by K](https://leetcode.com/problems/smallest-integer-divisible-by-k/) | [C++](./C++/smallest-integer-divisible-by-k.cpp) [Python](./Python/smallest-integer-divisible-by-k.py) | _O(k)_ | _O(1)_      | Medium         ||
1017 | [Convert to Base -2](https://leetcode.com/problems/convert-to-base-2/) | [C++](./C++/convert-to-base-2.cpp) [Python](./Python/convert-to-base-2.py) | _O(logn)_ | _O(1)_      | Medium         ||
1025 | [Divisor Game](https://leetcode.com/problems/divisor-game/) | [C++](./C++/divisor-game.cpp) [Python](./Python/divisor-game.py) | _O(1)_ | _O(1)_      | Easy         || DP
1037 | [Valid Boomerang](https://leetcode.com/problems/valid-boomerang/) | [C++](./C++/valid-boomerang.cpp) [Python](./Python/valid-boomerang.py) | _O(1)_ | _O(1)_      | Easy         ||
1041 | [Robot Bounded In Circle](https://leetcode.com/problems/robot-bounded-in-circle/) | [C++](./C++/robot-bounded-in-circle.cpp) [Python](./Python/robot-bounded-in-circle.py) | _O(n)_ | _O(1)_      | Medium         ||
1067 | [Digit Count in Range](https://leetcode.com/problems/digit-count-in-range/) | [C++](./C++/digit-count-in-range.cpp)  [Python](./Python/digit-count-in-range.py)  | _O(logn)_ | _O(1)_ | Hard        | 🔒, variant of [Number of Digit One](https://leetcode.com/problems/number-of-digit-one/) |
1073 | [Adding Two Negabinary Numbers](https://leetcode.com/problems/adding-two-negabinary-numbers/) | [C++](./C++/adding-two-negabinary-numbers.cpp) [Python](./Python/adding-two-negabinary-numbers.py) | _O(n)_ | _O(n)_      | Medium         ||
1079 | [Letter Tile Possibilities](https://leetcode.com/problems/letter-tile-possibilities/) | [C++](./C++/letter-tile-possibilities.cpp) [Python](./Python/letter-tile-possibilities.py) | _O(n^2)_ | _O(n)_      | Medium         || Generating Function, Backtracking
1088 | [Confusing Number II](https://leetcode.com/problems/confusing-number-ii/) | [C++](./C++/confusing-number-ii.cpp) [Python](./Python/confusing-number-ii.py) | _O(logn)_ | _O(logn)_ |  Hard | 🔒 |
1103 | [Distribute Candies to People](https://leetcode.com/problems/distribute-candies-to-people/) | [C++](./C++/distribute-candies-to-people.cpp) [Python](./Python/distribute-candies-to-people.py) | _O(n + logc)_ | _O(1)_ |  Easy | | Binary Search
1118 | [Number of Days in a Month](https://leetcode.com/problems/number-of-days-in-a-month/) | [C++](./C++/number-of-days-in-a-month.cpp) [Python](./Python/number-of-days-in-a-month.py) | _O(1)_ | _O(1)_ |  Easy | 🔒 |
1121 | [Divide Array Into Increasing Sequences](https://leetcode.com/problems/divide-array-into-increasing-sequences/) | [C++](./C++/divide-array-into-increasing-sequences.cpp) [Python](./Python/divide-array-into-increasing-sequences.py) | _O(n)_ | _O(1)_ |  Hard | 🔒 |
1128 | [Number of Equivalent Domino Pairs](https://leetcode.com/problems/number-of-equivalent-domino-pairs/) | [C++](./C++/number-of-equivalent-domino-pairs.cpp) [Python](./Python/number-of-equivalent-domino-pairs.py) | _O(n)_ | _O(n)_ |  Easy ||
1131 | [Maximum of Absolute Value Expression](https://leetcode.com/problems/maximum-of-absolute-value-expression/) | [C++](./C++/maximum-of-absolute-value-expression.cpp) [Python](./Python/maximum-of-absolute-value-expression.py) | _O(n)_ | _O(1)_ |  Medium ||
1134 | [Armstrong Number](https://leetcode.com/problems/armstrong-number/) | [C++](./C++/armstrong-number.cpp) [Python](./Python/armstrong-number.py) | _O(klogk)_ | _O(k)_ |  Easy | 🔒 |
1150 | [Check If a Number Is Majority Element in a Sorted Array](https://leetcode.com/problems/check-if-a-number-is-majority-element-in-a-sorted-array/) | [C++](./C++/check-if-a-number-is-majority-element-in-a-sorted-array.cpp) [Python](./Python/check-if-a-number-is-majority-element-in-a-sorted-array.py) | _O(nlogn)_ | _O(1)_ |  Easy |🔒| Binary Search
1157 | [Online Majority Element In Subarray](https://leetcode.com/problems/online-majority-element-in-subarray/) | [C++](./C++/online-majority-element-in-subarray.cpp) [Python](./Python/online-majority-element-in-subarray.py) | ctor: _O(n)_<br>query: _O(klogn)_ | _O(n)_ |  Hard || Binary Search, Segment Tree, `Boyer–Moore Majority Vote Algorithm`
1154 | [Day of the Year](https://leetcode.com/problems/day-of-the-year/) | [C++](./C++/day-of-the-year.cpp) [Python](./Python/day-of-the-year.py) | _O(1)_ | _O(1)_ |  Easy ||
1175 | [Prime Arrangements](https://leetcode.com/problems/prime-arrangements/) | [C++](./C++/prime-arrangements.cpp) [Python](./Python/prime-arrangements.py) | _O(nlog(logn))_ | _O(n)_ |  Easy || `Sieve of Eratosthenes`
1185 | [Day of the Week](https://leetcode.com/problems/day-of-the-week/) | [C++](./C++/day-of-the-week.cpp) [Python](./Python/day-of-the-week.py) | _O(1)_ | _O(1)_ |  Easy || `Zeller Formula`
1197 | [Minimum Knight Moves](https://leetcode.com/problems/minimum-knight-moves/) | [C++](./C++/minimum-knight-moves.cpp) [Python](./Python/minimum-knight-moves.py) | _O(1)_ | _O(1)_ | Medium |🔒| DP, Math |
1217 | [Play with Chips](https://leetcode.com/problems/play-with-chips/) | [C++](./C++/play-with-chips.cpp) [Python](./Python/play-with-chips.py) | _O(n)_ | _O(1)_ | Medium |||
1227 | [Airplane Seat Assignment Probability](https://leetcode.com/problems/airplane-seat-assignment-probability/) | [C++](./C++/airplane-seat-assignment-probability.cpp) [Python](./Python/airplane-seat-assignment-probability.py) | _O(1)_ | _O(1)_ | Medium |||
1232 | [Check If It Is a Straight Line](https://leetcode.com/problems/check-if-it-is-a-straight-line/) | [C++](./C++/check-if-it-is-a-straight-line.cpp) [Python](./Python/check-if-it-is-a-straight-line.py) | _O(1)_ | _O(1)_ | Easy |||
1237 | [Find Positive Integer Solution for a Given Equation](https://leetcode.com/problems/find-positive-integer-solution-for-a-given-equation/) | [C++](./C++/find-positive-integer-solution-for-a-given-equation.cpp) [Python](./Python/find-positive-integer-solution-for-a-given-equation.py) | _O(n)_ | _O(1)_ | Easy |||
1238 | [Circular Permutation in Binary Representation](https://leetcode.com/problems/circular-permutation-in-binary-representation/)     | [C++](./C++/circular-permutation-in-binary-representation.cpp) [Python](./Python/circular-permutation-in-binary-representation.py)  | _O(2^n)_        | _O(1)_          | Medium         | variant of [Gray Code](https://leetcode.com/problems/gray-code/) |
1250 | [Check If It Is a Good Array](https://leetcode.com/problems/check-if-it-is-a-good-array/) | [C++](./C++/check-if-it-is-a-good-array.cpp) [Python](./Python/check-if-it-is-a-good-array.py) | _O(n)_ | _O(1)_ | Hard || `Bézout's identity` |
1256 | [Encode Number](https://leetcode.com/problems/encode-number/)     | [C++](./C++/encode-number.cpp) [Python](./Python/encode-number.py)  | _O(logn)_        | _O(1)_          | Medium         | |
1259 | [Handshakes That Don't Cross](https://leetcode.com/problems/handshakes-that-dont-cross/)     | [C++](./C++/handshakes-that-dont-cross.cpp) [Python](./Python/handshakes-that-dont-cross.py)  | _O(n)_        | _O(1)_          | Hard         | | `Catalan Number`, DP
1266 | [Minimum Time Visiting All Points](https://leetcode.com/problems/minimum-time-visiting-all-points/)     | [C++](./C++/minimum-time-visiting-all-points.cpp) [Python](./Python/minimum-time-visiting-all-points.py)  | _O(n)_        | _O(1)_          | Easy         | |
1276 | [Number of Burgers with No Waste of Ingredients](https://leetcode.com/problems/number-of-burgers-with-no-waste-of-ingredients/)     | [C++](./C++/number-of-burgers-with-no-waste-of-ingredients.cpp) [Python](./Python/number-of-burgers-with-no-waste-of-ingredients.py)  | _O(1)_        | _O(1)_          | Medium         | |
1281 | [Subtract the Product and Sum of Digits of an Integer](https://leetcode.com/problems/subtract-the-product-and-sum-of-digits-of-an-integer/)     | [C++](./C++/subtract-the-product-and-sum-of-digits-of-an-integer.cpp) [Python](./Python/subtract-the-product-and-sum-of-digits-of-an-integer.py)  | _O(logn)_        | _O(1)_          | Easy         | |
1300 | [Sum of Mutated Array Closest to Target](https://leetcode.com/problems/sum-of-mutated-array-closest-to-target/)     | [C++](./C++/sum-of-mutated-array-closest-to-target.cpp) [Python](./Python/sum-of-mutated-array-closest-to-target.py)  | _O(nlogn)_        | _O(1)_          | Medium         | | Binary Search
1317 | [Convert Integer to the Sum of Two No-Zero Integers](https://leetcode.com/problems/convert-integer-to-the-sum-of-two-no-zero-integers/)     | [C++](./C++/convert-integer-to-the-sum-of-two-no-zero-integers.cpp) [Python](./Python/convert-integer-to-the-sum-of-two-no-zero-integers.py)  | _O(logn)_        | _O(1)_          | Easy         | |
1323 | [Maximum 69 Number](https://leetcode.com/problems/maximum-69-number/)     | [C++](./C++/maximum-69-number.cpp) [Python](./Python/maximum-69-number.py)  | _O(logn)_        | _O(1)_          | Easy         | |
1330 | [Reverse Subarray To Maximize Array Value](https://leetcode.com/problems/reverse-subarray-to-maximize-array-value/)     | [C++](./C++/reverse-subarray-to-maximize-array-value.cpp) [Python](./Python/reverse-subarray-to-maximize-array-value.py)  | _O(n)_        | _O(1)_          | Hard         | |
1344 | [Angle Between Hands of a Clock](https://leetcode.com/problems/angle-between-hands-of-a-clock/)     | [C++](./C++/angle-between-hands-of-a-clock.cpp) [Python](./Python/angle-between-hands-of-a-clock.py)  | _O(1)_        | _O(1)_          | Medium         | |
1359 | [Count All Valid Pickup and Delivery Options](https://leetcode.com/problems/count-all-valid-pickup-and-delivery-options/)     | [C++](./C++/count-all-valid-pickup-and-delivery-options.cpp) [Python](./Python/count-all-valid-pickup-and-delivery-options.py)  | _O(n)_        | _O(1)_          | Hard         | |
1360 | [Number of Days Between Two Dates](https://leetcode.com/problems/number-of-days-between-two-dates/) | [C++](./C++/number-of-days-between-two-dates.cpp) [Python](./Python/number-of-days-between-two-dates.py) | _O(1)_ | _O(1)_ |  Easy | variant of [Day of the Year](https://leetcode.com/problems/day-of-the-year/) |
1362 | [Closest Divisors](https://leetcode.com/problems/closest-divisors/) | [C++](./C++/closest-divisors.cpp) [Python](./Python/closest-divisors.py) | _O(sqrt(n))_ | _O(1)_ |  Medium | |
1363 | [Largest Multiple of Three](https://leetcode.com/problems/largest-multiple-of-three/) | [C++](./C++/largest-multiple-of-three.cpp) [Python](./Python/largest-multiple-of-three.py) | _O(n)_ | _O(1)_ |  Hard | |
1390 | [Four Divisors](https://leetcode.com/problems/four-divisors/) | [C++](./C++/four-divisors.cpp) [Python](./Python/four-divisors.py) | _O(n * sqrt(n))_ | _O(1)_ |  Medium | |
1401 | [Circle and Rectangle Overlapping](https://leetcode.com/problems/circle-and-rectangle-overlapping/) | [C++](./C++/circle-and-rectangle-overlapping.cpp) [Python](./Python/circle-and-rectangle-overlapping.py) | _O(1)_ | _O(1)_ |  Medium | |
1415 | [The k-th Lexicographical String of All Happy Strings of Length n](https://leetcode.com/problems/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n/) | [C++](./C++/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n.cpp) [Python](./Python/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n.py) | _O(n)_ | _O(1)_ |  Medium | |
1442 | [Count Triplets That Can Form Two Arrays of Equal XOR](https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor/) | [C++](./C++/count-triplets-that-can-form-two-arrays-of-equal-xor.cpp) [Python](./Python/count-triplets-that-can-form-two-arrays-of-equal-xor.py) | _O(n)_ | _O(n)_ |  Medium | |
1447 | [Simplified Fractions](https://leetcode.com/problems/simplified-fractions/) | [C++](./C++/simplified-fractions.cpp) [Python](./Python/simplified-fractions.py) | _O(n^2 * logn)_ | _O(n^2)_ |  Medium | |
1486 | [XOR Operation in an Array](https://leetcode.com/problems/xor-operation-in-an-array/) | [C++](./C++/xor-operation-in-an-array.cpp) [Python](./Python/xor-operation-in-an-array.py) | _O(1)_ | _O(1)_ |  Easy | |
1492 | [The kth Factor of n](https://leetcode.com/problems/the-kth-factor-of-n/) | [C++](./C++/the-kth-factor-of-n.cpp) [Python](./Python/the-kth-factor-of-n.py) | _O(sqrt(n))_ | _O(1)_ |  Medium | |
1497 | [Check If Array Pairs Are Divisible by k](https://leetcode.com/problems/check-if-array-pairs-are-divisible-by-k/) | [C++](./C++/check-if-array-pairs-are-divisible-by-k.cpp) [Python](./Python/check-if-array-pairs-are-divisible-by-k.py) | _O(n)_ | _O(k)_ |  Medium | |
1512 | [Number of Good Pairs](https://leetcode.com/problems/number-of-good-pairs/) | [C++](./C++/number-of-good-pairs.cpp) [Python](./Python/number-of-good-pairs.py) | _O(n)_ | _O(1)_ |  Easy | |
1513 | [Number of Substrings With Only 1s](https://leetcode.com/problems/number-of-substrings-with-only-1s/) | [C++](./C++/number-of-substrings-with-only-1s.cpp) [Python](./Python/number-of-substrings-with-only-1s.py) | _O(n)_ | _O(1)_ |  Medium | |
1525 | [Number of Good Ways to Split a String](https://leetcode.com/problems/number-of-good-ways-to-split-a-string/) | [C++](./C++/number-of-good-ways-to-split-a-string.cpp) [Python](./Python/number-of-good-ways-to-split-a-string.py) | _O(n)_ | _O(1)_ |  Medium | |
1537 | [Get the Maximum Score](https://leetcode.com/problems/get-the-maximum-score/) | [C++](./C++/get-the-maximum-score.cpp) [Python](./Python/get-the-maximum-score.py) | _O(m + n)_ | _O(1)_ |  Hard | |
1551 | [Minimum Operations to Make Array Equal](https://leetcode.com/problems/minimum-operations-to-make-array-equal/) | [C++](./C++/minimum-operations-to-make-array-equal.cpp) [Python](./Python/minimum-operations-to-make-array-equal.py) | _O(1)_ | _O(1)_ |  Medium | |
1611 | [Minimum One Bit Operations to Make Integers Zero](https://leetcode.com/problems/minimum-one-bit-operations-to-make-integers-zero/)     | [C++](./C++/minimum-one-bit-operations-to-make-integers-zero.cpp) [Python](./Python/minimum-one-bit-operations-to-make-integers-zero.py)  | _O(logn)_        | _O(1)_          | Hard         | variant of [Gray Code](https://leetcode.com/problems/gray-code/) |
1641 | [Count Sorted Vowel Strings](https://leetcode.com/problems/count-sorted-vowel-strings/) | [C++](./C++/count-sorted-vowel-strings.cpp) [Python](./Python/count-sorted-vowel-strings.py) | _O(1)_ | _O(1)_ |  Medium | | Binomial Coefficients
1643 | [Kth Smallest Instructions](https://leetcode.com/problems/kth-smallest-instructions/) | [C++](./C++/kth-smallest-instructions.cpp) [Python](./Python/kth-smallest-instructions.py) | _O((m + n)^2)_ | _O(1)_ |  Hard | | Binomial Coefficients
1735 | [Count Ways to Make Array With Product](https://leetcode.com/problems/count-ways-to-make-array-with-product/) | [C++](./C++/count-ways-to-make-array-with-product.cpp) [Python](./Python/count-ways-to-make-array-with-product.py) | _O(nlogn)_ | _O(logn)_ |  Hard | | Binomial Coefficients, `Euler's Theorem`, Modular Inverse
1739 | [Building Boxes](https://leetcode.com/problems/building-boxes/) | [C++](./C++/building-boxes.cpp) [Python](./Python/building-boxes.py) | _O(1)_ | _O(1)_ |  Hard | |
1744 | [Can You Eat Your Favorite Candy on Your Favorite Day?](https://leetcode.com/problems/can-you-eat-your-favorite-candy-on-your-favorite-day/) | [C++](./C++/can-you-eat-your-favorite-candy-on-your-favorite-day.cpp) [Python](./Python/can-you-eat-your-favorite-candy-on-your-favorite-day.py) | _O(n)_ | _O(n)_ |  Medium | | Prefix Sum
1753 | [Maximum Score From Removing Stones](https://leetcode.com/problems/maximum-score-from-removing-stones/) | [C++](./C++/maximum-score-from-removing-stones.cpp) [Python](./Python/maximum-score-from-removing-stones.py) | _O(1)_ | _O(1)_ |  Medium | |
1776 | [Car Fleet II](https://leetcode.com/problems/car-fleet-ii/) | [C++](./C++/car-fleet-ii.cpp) [Python](./Python/car-fleet-ii.py) | _O(n)_ | _O(n)_ |  Hard | | Mono Stack
1780 | [Check if Number is a Sum of Powers of Three](https://leetcode.com/problems/check-if-number-is-a-sum-of-powers-of-three/) | [C++](./C++/check-if-number-is-a-sum-of-powers-of-three.cpp) [Python](./Python/check-if-number-is-a-sum-of-powers-of-three.py) | _O(logn)_ | _O(1)_ |  Medium | |
1806 | [Minimum Number of Operations to Reinitialize a Permutation](https://leetcode.com/problems/minimum-number-of-operations-to-reinitialize-a-permutation/) | [C++](./C++/minimum-number-of-operations-to-reinitialize-a-permutation.cpp) [Python](./Python/minimum-number-of-operations-to-reinitialize-a-permutation.py) | _O(sqrt(n))_ | _O(sqrt(n))_ |  Medium | | Discrete Logarithm, Multiplicative Order
1808 | [Maximize Number of Nice Divisors](https://leetcode.com/problems/maximize-number-of-nice-divisors/) | [C++](./C++/maximize-number-of-nice-divisors.cpp) [Python](./Python/maximize-number-of-nice-divisors.py) | _O(logn)_ | _O(1)_ |  Medium | variant of [Integer Break](https://leetcode.com/problems/integer-break/)  |
1812 | [Determine Color of a Chessboard Square](https://leetcode.com/problems/determine-color-of-a-chessboard-square/) | [C++](./C++/determine-color-of-a-chessboard-square.cpp) [Python](./Python/determine-color-of-a-chessboard-square.py) | _O(1)_ | _O(1)_ |  Easy |  |
1819 | [Number of Different Subsequences GCDs](https://leetcode.com/problems/number-of-different-subsequences-gcds/) | [C++](./C++/number-of-different-subsequences-gcds.cpp) [Python](./Python/number-of-different-subsequences-gcds.py) | _O(n + mlogm)_ | _O(n)_ |  Hard |  |
1822 | [Sign of the Product of an Array](https://leetcode.com/problems/sign-of-the-product-of-an-array/) | [C++](./C++/sign-of-the-product-of-an-array.cpp) [Python](./Python/sign-of-the-product-of-an-array.py) | _O(n)_ | _O(1)_ |  Easy |  |
1823 | [Find the Winner of the Circular Game](https://leetcode.com/problems/find-the-winner-of-the-circular-game/) | [C++](./C++/find-the-winner-of-the-circular-game.cpp) [Python](./Python/find-the-winner-of-the-circular-game.py) | _O(n)_ | _O(1)_ |  Medium |  |
1828 | [Queries on Number of Points Inside a Circle](https://leetcode.com/problems/queries-on-number-of-points-inside-a-circle/) | [C++](./C++/queries-on-number-of-points-inside-a-circle.cpp) [Python](./Python/queries-on-number-of-points-inside-a-circle.py) | _O(q * n)_ | _O(1)_ |  Medium |  |
1830 | [Minimum Number of Operations to Make String Sorted](https://leetcode.com/problems/minimum-number-of-operations-to-make-string-sorted/) | [C++](./C++/minimum-number-of-operations-to-make-string-sorted.cpp) [Python](./Python/minimum-number-of-operations-to-make-string-sorted.py) | _O(n)_ | _O(max_n)_ |  Hard |  | Modular Inverse |
1835 | [Find XOR Sum of All Pairs Bitwise AND](https://leetcode.com/problems/find-xor-sum-of-all-pairs-bitwise-and/) | [C++](./C++/find-xor-sum-of-all-pairs-bitwise-and.cpp) [Python](./Python/find-xor-sum-of-all-pairs-bitwise-and.py) | _O(n)_ | _O(1)_ |  Hard |  | |
1837 | [Sum of Digits in Base K](https://leetcode.com/problems/sum-of-digits-in-base-k/) | [C++](./C++/sum-of-digits-in-base-k.cpp) [Python](./Python/sum-of-digits-in-base-k.py) | _O(logn)_ | _O(1)_ |  Easy |  | |
1860 | [Incremental Memory Leak](https://leetcode.com/problems/incremental-memory-leak/) | [C++](./C++/incremental-memory-leak.cpp) [Python](./Python/incremental-memory-leak.py) | _O(1)_ | _O(1)_ |  Medium | [GCJ2020 - Round 2](https://codingcompetitions.withgoogle.com/codejam/round/000000000019ffb9/00000000003384ea) | |
1862 | [Sum of Floored Pairs](https://leetcode.com/problems/sum-of-floored-pairs/) | [C++](./C++/sum-of-floored-pairs.cpp) [Python](./Python/sum-of-floored-pairs.py) | _O(nlogn)_ | _O(n)_ |  Hard |  | |
1863 | [Sum of All Subset XOR Totals](https://leetcode.com/problems/sum-of-all-subset-xor-totals/) | [C++](./C++/sum-of-all-subset-xor-totals.cpp) [Python](./Python/sum-of-all-subset-xor-totals.py) | _O(n)_ | _O(1)_ |  Easy |  | |
1884 | [Egg Drop With 2 Eggs and N Floors](https://leetcode.com/problems/egg-drop-with-2-eggs-and-n-floors/) | [C++](./C++/egg-drop-with-2-eggs-and-n-floors.cpp) [Python](./Python/egg-drop-with-2-eggs-and-n-floors.py) | _O(1)_ | _O(1)_ |  Medium |  | DP |
1904 | [The Number of Full Rounds You Have Played](https://leetcode.com/problems/the-number-of-full-rounds-you-have-played/) | [C++](./C++/the-number-of-full-rounds-you-have-played.cpp) [Python](./Python/the-number-of-full-rounds-you-have-played.py) | _O(1)_ | _O(1)_ |  Medium |  | |
1916 | [Count Ways to Build Rooms in an Ant Colony](https://leetcode.com/problems/count-ways-to-build-rooms-in-an-ant-colony/) | [C++](./C++/count-ways-to-build-rooms-in-an-ant-colony.cpp) [Python](./Python/count-ways-to-build-rooms-in-an-ant-colony.py) | _O(n)_ | _O(n)_ |  Hard |  | DFS, Tree |
1922 | [Count Good Numbers](https://leetcode.com/problems/count-good-numbers/) | [C++](./C++/count-good-numbers.cpp) [Python](./Python/count-good-numbers.py) | _O(logn)_ | _O(1)_ |  Medium |  | |
1945 | [Sum of Digits of String After Convert](https://leetcode.com/problems/sum-of-digits-of-string-after-convert/) | [C++](./C++/sum-of-digits-of-string-after-convert.cpp) [Python](./Python/sum-of-digits-of-string-after-convert.py) | _O(n)_ | _O(1)_ |  Easy |  | |
1952 | [Three Divisors](https://leetcode.com/problems/three-divisors/) | [C++](./C++/three-divisors.cpp) [Python](./Python/three-divisors.py) | _O(sqrt(n))_ | _O(1)_ |  Easy |  | |
1954 | [Minimum Garden Perimeter to Collect Enough Apples](https://leetcode.com/problems/minimum-garden-perimeter-to-collect-enough-apples/) | [C++](./C++/minimum-garden-perimeter-to-collect-enough-apples.cpp) [Python](./Python/minimum-garden-perimeter-to-collect-enough-apples.py) | _O(1)_ | _O(1)_ |  Medium |  | Binary Search, `Cardano's Formula` |
1969 | [Minimum Non-Zero Product of the Array Elements](https://leetcode.com/problems/minimum-non-zero-product-of-the-array-elements/) | [C++](./C++/minimum-non-zero-product-of-the-array-elements.cpp) [Python](./Python/minimum-non-zero-product-of-the-array-elements.py) | _O(min(p, logM))_ | _O(1)_ |  Medium |  | |
1979 | [Find Greatest Common Divisor of Array](https://leetcode.com/problems/find-greatest-common-divisor-of-array/) | [C++](./C++/find-greatest-common-divisor-of-array.cpp) [Python](./Python/find-greatest-common-divisor-of-array.py) | _O(n)_ | _O(1)_ |  Easy |  | |
1980 | [Find Unique Binary String](https://leetcode.com/problems/find-unique-binary-string/) | [C++](./C++/find-unique-binary-string.cpp) [Python](./Python/find-unique-binary-string.py) | _O(n)_ | _O(1)_ |  Medium |  | `Cantor Diagonalization` |
1982 | [Find Array Given Subset Sums](https://leetcode.com/problems/find-array-given-subset-sums/)|[C++](./C++/find-array-given-subset-sums.cpp) [Python](./Python/find-array-given-subset-sums.py)| _O(n * 2^n)_     | _O(1)_         | Hard         | | Math, DP, OrderedDict |
2001 | [Number of Pairs of Interchangeable Rectangles](https://leetcode.com/problems/number-of-pairs-of-interchangeable-rectangles/)|[C++](./C++/number-of-pairs-of-interchangeable-rectangles.cpp) [Python](./Python/number-of-pairs-of-interchangeable-rectangles.py)| _O(n)_     | _O(n)_         | Medium         | | Math |
2005 | [Subtree Removal Game with Fibonacci Tree](https://leetcode.com/problems/subtree-removal-game-with-fibonacci-tree/)|[C++](./C++/subtree-removal-game-with-fibonacci-tree.cpp) [Python](./Python/subtree-removal-game-with-fibonacci-tree.py)| _O(1)_     | _O(1)_         | Hard         |🔒| Math, `Sprague-Grundy Theorem`, `Colon Principle` |
2028 | [Find Missing Observations](https://leetcode.com/problems/find-missing-observations/)|[C++](./C++/find-missing-observations.cpp) [Python](./Python/find-missing-observations.py)| _O(n)_     | _O(1)_         | Medium         | | |
2029 | [Stone Game IX](https://leetcode.com/problems/stone-game-ix/)|[C++](./C++/stone-game-ix.cpp) [Python](./Python/stone-game-ix.py)| _O(n)_     | _O(1)_         | Medium         | |
2063 | [Vowels of All Substrings](https://leetcode.com/problems/vowels-of-all-substrings/)|[C++](./C++/vowels-of-all-substrings.cpp) [Python](./Python/vowels-of-all-substrings.py)| _O(n)_     | _O(1)_         | Medium         | | Combinatorics
2073 | [Time Needed to Buy Tickets](https://leetcode.com/problems/time-needed-to-buy-tickets/)|[C++](./C++/time-needed-to-buy-tickets.cpp) [Python](./Python/time-needed-to-buy-tickets.py)| _O(n)_     | _O(1)_         | Easy         | | Simulation, Math
2083 | [Substrings That Begin and End With the Same Letter](https://leetcode.com/problems/substrings-that-begin-and-end-with-the-same-letter/)|[C++](./C++/substrings-that-begin-and-end-with-the-same-letter.cpp) [Python](./Python/substrings-that-begin-and-end-with-the-same-letter.py)| _O(n)_     | _O(1)_         | Medium         | 🔒 | Combinatorics
2091 | [Removing Minimum and Maximum From Array](https://leetcode.com/problems/removing-minimum-and-maximum-from-array/)|[C++](./C++/removing-minimum-and-maximum-from-array.cpp) [Python](./Python/removing-minimum-and-maximum-from-array.py)| _O(n)_     | _O(1)_         | Medium         | | Math
2110 | [Number of Smooth Descent Periods of a Stock](https://leetcode.com/problems/number-of-smooth-descent-periods-of-a-stock/)|[C++](./C++/number-of-smooth-descent-periods-of-a-stock.cpp) [Python](./Python/number-of-smooth-descent-periods-of-a-stock.py)| _O(n)_     | _O(1)_         | Medium         | | Math, Combinatorics
2117 | [Abbreviating the Product of a Range](https://leetcode.com/problems/abbreviating-the-product-of-a-range/)|[C++](./C++/abbreviating-the-product-of-a-range.cpp) [Python](./Python/abbreviating-the-product-of-a-range.py)| _O(r - l)_     | _O(1)_         | Hard         | | Math
2119 | [A Number After a Double Reversal](https://leetcode.com/problems/a-number-after-a-double-reversal/)|[C++](./C++/a-number-after-a-double-reversal.cpp) [Python](./Python/a-number-after-a-double-reversal.py)| _O(1)_     | _O(1)_         | Easy         | | Math
2125 | [Number of Laser Beams in a Bank](https://leetcode.com/problems/number-of-laser-beams-in-a-bank/)|[C++](./C++/number-of-laser-beams-in-a-bank.cpp) [Python](./Python/number-of-laser-beams-in-a-bank.py)| _O(m * n)_     | _O(1)_         | Medium         | | Math
2133 | [Check if Every Row and Column Contains All Numbers](https://leetcode.com/problems/check-if-every-row-and-column-contains-all-numbers/)|[C++](./C++/check-if-every-row-and-column-contains-all-numbers.cpp) [Python](./Python/check-if-every-row-and-column-contains-all-numbers.py)| _O(n^2)_     | _O(n)_         | Easy         | | Math
2145 | [Count the Hidden Sequences](https://leetcode.com/problems/count-the-hidden-sequences/)|[C++](./C++/count-the-hidden-sequences.cpp) [Python](./Python/count-the-hidden-sequences.py)| _O(n)_     | _O(1)_         | Medium         | | Math
2148 | [Count Elements With Strictly Smaller and Greater Elements](https://leetcode.com/problems/count-elements-with-strictly-smaller-and-greater-elements/)|[C++](./C++/count-elements-with-strictly-smaller-and-greater-elements.cpp) [Python](./Python/count-elements-with-strictly-smaller-and-greater-elements.py)| _O(n)_     | _O(1)_         | Easy         | | Math
2152 | [Minimum Number of Lines to Cover Points](https://leetcode.com/problems/minimum-number-of-lines-to-cover-points/)|[C++](./C++/minimum-number-of-lines-to-cover-points.cpp) [Python](./Python/minimum-number-of-lines-to-cover-points.py)| _O(n * 2^n)_     | _O(n^2)_         | Medium         | 🔒 | Math, Hash Table, Bitmasks

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
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<br/>

## Sort
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1054 | [Distant Barcodes](https://leetcode.com/problems/distant-barcodes/) | [C++](./C++/distant-barcodes.cpp) [Python](./Python/distant-barcodes.py) | _O(klogk)_ | _O(k)_ | Medium |  variant of [Rearrange String k Distance Apart](https://leetcode.com/problems/rearrange-string-k-distance-apart/) ||
1086 | [High Five](https://leetcode.com/problems/high-five/) | [C++](./C++/high-five.cpp) [Python](./Python/high-five.py) | _O(nlogn)_ | _O(n)_ | Easy | 🔒||
1094 | [Car Pooling](https://leetcode.com/problems/car-pooling/) | [C++](./C++/car-pooling.cpp) [Python](./Python/car-pooling.py) | _O(nlogn)_   | _O(n)_        | Medium         | variant of [Meeting Rooms II](https://leetcode.com/problems/meeting-rooms-ii/) | |
1122 | [Relative Sort Array](https://leetcode.com/problems/relative-sort-array/) | [C++](./C++/relative-sort-array.cpp) [Python](./Python/relative-sort-array.py) | _O(nlogn)_   | _O(n)_        | Easy         ||
1229 | [Meeting Scheduler](https://leetcode.com/problems/meeting-scheduler/) | [C++](./C++/meeting-scheduler.cpp) [Python](./Python/meeting-scheduler.py) | _O(nlogn)_   | _O(n)_        | Medium         || Line Sweep, Heap
1356 | [Sort Integers by The Number of 1 Bits](https://leetcode.com/problems/sort-integers-by-the-number-of-1-bits/) | [C++](./C++/sort-integers-by-the-number-of-1-bits.cpp) [Python](./Python/sort-integers-by-the-number-of-1-bits.py) | _O(nlogn)_   | _O(1)_        | Easy         || Bit Manipulation
1365 | [How Many Numbers Are Smaller Than the Current Number](https://leetcode.com/problems/how-many-numbers-are-smaller-than-the-current-number/) | [C++](./C++/how-many-numbers-are-smaller-than-the-current-number.cpp) [Python](./Python/how-many-numbers-are-smaller-than-the-current-number.py) | _O(n + m)_   | _O(m)_        | Easy         || Counting Sort
1366 | [Rank Teams by Votes](https://leetcode.com/problems/rank-teams-by-votes/) | [C++](./C++/rank-teams-by-votes.cpp) [Python](./Python/rank-teams-by-votes.py) | _O(m * (n + mlogm))_   | _O(m^2)_        | Medium         ||
1451 | [Rearrange Words in a Sentence](https://leetcode.com/problems/rearrange-words-in-a-sentence/) | [C++](./C++/rearrange-words-in-a-sentence.cpp) [Python](./Python/rearrange-words-in-a-sentence.py) | _O(nlogn)_   | _O(n)_        | Medium         || String
1481 | [Least Number of Unique Integers after K Removals](https://leetcode.com/problems/least-number-of-unique-integers-after-k-removals/) | [C++](./C++/least-number-of-unique-integers-after-k-removals.cpp) [Python](./Python/least-number-of-unique-integers-after-k-removals.py) | _O(n)_   | _O(n)_        | Medium         || Counting Sort
1509 | [Minimum Difference Between Largest and Smallest Value in Three Moves](https://leetcode.com/problems/minimum-difference-between-largest-and-smallest-value-in-three-moves/) | [C++](./C++/minimum-difference-between-largest-and-smallest-value-in-three-moves.cpp) [Python](./Python/minimum-difference-between-largest-and-smallest-value-in-three-moves.py) | _O(n + klogk)_   | _O(1)_        | Medium         || Quick Select
1523 | [Count Odd Numbers in an Interval Range](https://leetcode.com/problems/count-odd-numbers-in-an-interval-range/) | [C++](./C++/count-odd-numbers-in-an-interval-range.cpp) [Python](./Python/count-odd-numbers-in-an-interval-range.py) | _O(1)_   | _O(1)_        | Easy         ||
1561 | [Maximum Number of Coins You Can Get](https://leetcode.com/problems/maximum-number-of-coins-you-can-get/) | [C++](./C++/maximum-number-of-coins-you-can-get.cpp) [Python](./Python/maximum-number-of-coins-you-can-get.py) | _O(nlogn)_   | _O(1)_        | Medium         ||
1588 | [Sum of All Odd Length Subarrays](https://leetcode.com/problems/sum-of-all-odd-length-subarrays/) | [C++](./C++/sum-of-all-odd-length-subarrays.cpp) [Python](./Python/sum-of-all-odd-length-subarrays.py) | _O(n)_   | _O(1)_        | Easy         ||
1608 | [Special Array With X Elements Greater Than or Equal X](https://leetcode.com/problems/special-array-with-x-elements-greater-than-or-equal-x/) | [C++](./C++/special-array-with-x-elements-greater-than-or-equal-x.cpp) [Python](./Python/special-array-with-x-elements-greater-than-or-equal-x.py) | _O(n)_   | _O(1)_        | Easy         | variant of [H-Index](https://leetcode.com/problems/h-index/) | Counting Sort, Binary Search
1620 | [Coordinate With Maximum Network Quality](https://leetcode.com/problems/coordinate-with-maximum-network-quality/) | [C++](./C++/coordinate-with-maximum-network-quality.cpp) [Python](./Python/coordinate-with-maximum-network-quality.py) | _O(n^2)_ | _O(1)_| Medium | |
1621 | [Number of Sets of K Non-Overlapping Line Segments](https://leetcode.com/problems/number-of-sets-of-k-non-overlapping-line-segments/) | [C++](./C++/number-of-sets-of-k-non-overlapping-line-segments.cpp) [Python](./Python/number-of-sets-of-k-non-overlapping-line-segments.py) | _O(1)_ | _O(n)_| Medium | |  Binomial Coefficients, `Euler's Theorem`
1630 | [Arithmetic Subarrays](https://leetcode.com/problems/arithmetic-subarrays/) | [C++](./C++/arithmetic-subarrays.cpp) [Python](./Python/arithmetic-subarrays.py) | _O(n * q)_ | _O(n)_| Medium | | Arithmetic Series
1636 | [Sort Array by Increasing Frequency](https://leetcode.com/problems/sort-array-by-increasing-frequency/) | [C++](./C++/sort-array-by-increasing-frequency.cpp) [Python](./Python/sort-array-by-increasing-frequency.py) | _O(nlogn)_ | _O(n)_| Easy | |
1637 | [Widest Vertical Area Between Two Points Containing No Points](https://leetcode.com/problems/widest-vertical-area-between-two-points-containing-no-points/) | [C++](./C++/widest-vertical-area-between-two-points-containing-no-points.cpp) [Python](./Python/widest-vertical-area-between-two-points-containing-no-points.py) | _O(nlogn)_ | _O(n)_| Medium | |
1680 | [Concatenation of Consecutive Binary Numbers](https://leetcode.com/problems/concatenation-of-consecutive-binary-numbers/) | [C++](./C++/concatenation-of-consecutive-binary-numbers.cpp) [Python](./Python/concatenation-of-consecutive-binary-numbers.py) | _O(n)_ | _O(1)_| Medium | |
1685 | [Sum of Absolute Differences in a Sorted Array](https://leetcode.com/problems/sum-of-absolute-differences-in-a-sorted-array/) | [C++](./C++/sum-of-absolute-differences-in-a-sorted-array.cpp) [Python](./Python/sum-of-absolute-differences-in-a-sorted-array.py) | _O(n)_ | _O(1)_| Medium | |
1688 | [Count of Matches in Tournament](https://leetcode.com/problems/count-of-matches-in-tournament/) | [C++](./C++/count-of-matches-in-tournament.cpp) [Python](./Python/count-of-matches-in-tournament.py) | _O(1)_ | _O(1)_| Easy | |
1703 | [Minimum Adjacent Swaps for K Consecutive Ones](https://leetcode.com/problems/minimum-adjacent-swaps-for-k-consecutive-ones/) | [C++](./C++/minimum-adjacent-swaps-for-k-consecutive-ones.cpp) [Python](./Python/minimum-adjacent-swaps-for-k-consecutive-ones.py) | _O(n)_ | _O(n)_| Hard | | Math, Median, Prefix Sum
1716 | [Calculate Money in Leetcode Bank](https://leetcode.com/problems/calculate-money-in-leetcode-bank/) | [C++](./C++/calculate-money-in-leetcode-bank.cpp) [Python](./Python/calculate-money-in-leetcode-bank.py) | _O(1)_ | _O(1)_| Easy | | Arithmetic Sequence
1772 | [Sort Features by Popularity](https://leetcode.com/problems/sort-features-by-popularity/) | [C++](./C++/sort-features-by-popularity.cpp) [Python](./Python/sort-features-by-popularity.py) | _O(n)_ | _O(1)_ | Medium | 🔒 ||
1847 | [Closest Room](https://leetcode.com/problems/closest-room/) | [C++](./C++/closest-room.cpp) [Python](./Python/closest-room.py) | _O(nlogn + klogk + klogn)_ | _O(n + k)_ | Hard | | Sort, Binary Search
1851 | [Minimum Interval to Include Each Query](https://leetcode.com/problems/minimum-interval-to-include-each-query/) | [C++](./C++/minimum-interval-to-include-each-query.cpp) [Python](./Python/minimum-interval-to-include-each-query.py) | _O(nlogn + klogk + klogn)_ | _O(n + k)_ | Hard | | Sort, Heap, Line Sweep
1859 | [Sorting the Sentence](https://leetcode.com/problems/sorting-the-sentence/) | [C++](./C++/sorting-the-sentence.cpp) [Python](./Python/sorting-the-sentence.py) | _O(n)_ | _O(n)_ | Easy | | Sort, String
1942 | [The Number of the Smallest Unoccupied Chair](https://leetcode.com/problems/the-number-of-the-smallest-unoccupied-chair/) | [C++](./C++/the-number-of-the-smallest-unoccupied-chair.cpp) [Python](./Python/the-number-of-the-smallest-unoccupied-chair.py) | _O(nlogn)_   | _O(n)_        | Medium         || Line Sweep, Heap
1943 | [Describe the Painting](https://leetcode.com/problems/describe-the-painting/) | [C++](./C++/describe-the-painting.cpp) [Python](./Python/describe-the-painting.py) | _O(nlogn)_   | _O(n)_        | Medium         || Line Sweep
1968 | [Array With Elements Not Equal to Average of Neighbors](https://leetcode.com/problems/array-with-elements-not-equal-to-average-of-neighbors/) | [C++](./C++/array-with-elements-not-equal-to-average-of-neighbors.cpp) [Python](./Python/array-with-elements-not-equal-to-average-of-neighbors.py) | _O(n)_  on average | _O(1)_        | Medium         | variant of [Wiggle Sort II](https://leetcode.com/problems/wiggle-sort-ii/) | Quick Select, Tri Partition |
1985 | [Find the Kth Largest Integer in the Array](https://leetcode.com/problems/find-the-kth-largest-integer-in-the-array/) | [C++](./C++/find-the-kth-largest-integer-in-the-array.cpp) [Python](./Python/find-the-kth-largest-integer-in-the-array.py) | _O(n)_ on average| _O(n)_ | Medium | | Quick Select |
1996 | [The Number of Weak Characters in the Game](https://leetcode.com/problems/the-number-of-weak-characters-in-the-game/) | [C++](./C++/the-number-of-weak-characters-in-the-game.cpp) [Python](./Python/the-number-of-weak-characters-in-the-game.py) | _O(nlogn)_ | _O(1)_ | Medium | | |
2015 | [Average Height of Buildings in Each Segment](https://leetcode.com/problems/average-height-of-buildings-in-each-segment/) | [C++](./C++/average-height-of-buildings-in-each-segment.cpp) [Python](./Python/average-height-of-buildings-in-each-segment.py) | _O(nlogn)_   | _O(n)_        | Medium         | 🔒 | Line Sweep
2021 | [Brightest Position on Street](https://leetcode.com/problems/brightest-position-on-street/) | [C++](./C++/brightest-position-on-street.cpp) [Python](./Python/brightest-position-on-street.py) | _O(nlogn)_   | _O(n)_        | Medium         | 🔒 | Line Sweep
2070 | [Most Beautiful Item for Each Query](https://leetcode.com/problems/most-beautiful-item-for-each-query/) | [C++](./C++/most-beautiful-item-for-each-query.cpp) [Python](./Python/most-beautiful-item-for-each-query.py) | _O(nlogn + qlogn)_ | _O(1)_ | Medium | | Sort, Binary Search |
2089 | [Find Target Indices After Sorting Array](https://leetcode.com/problems/find-target-indices-after-sorting-array/) | [C++](./C++/find-target-indices-after-sorting-array.cpp) [Python](./Python/find-target-indices-after-sorting-array.py) | _O(n)_ | _O(1)_ | Easy | | Counting Sort |

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## Two Pointers
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1004 | [Max Consecutive Ones III](https://leetcode.com/problems/max-consecutive-ones-iii/) | [C++](./C++/max-consecutive-ones-iii.cpp) [Python](./Python/max-consecutive-ones-iii.py) | _O(n)_ | _O(1)_ | Medium || Sliding Window
1033 | [Moving Stones Until Consecutive](https://leetcode.com/problems/moving-stones-until-consecutive/) | [C++](./C++/moving-stones-until-consecutive.cpp) [Python](./Python/moving-stones-until-consecutive.py) | _O(1)_ | _O(1)_      | Easy         ||
1040 | [Moving Stones Until Consecutive II](https://leetcode.com/problems/moving-stones-until-consecutive-ii/) | [C++](./C++/moving-stones-until-consecutive-ii.cpp) [Python](./Python/moving-stones-until-consecutive-ii.py) | _O(nlogn)_ | _O(1)_      | Medium         ||
1151 | [Minimum Swaps to Group All 1's Together](https://leetcode.com/problems/minimum-swaps-to-group-all-1s-together/) | [C++](./C++/minimum-swaps-to-group-all-1s-together.cpp) [Python](./Python/minimum-swaps-to-group-all-1s-together.py) | _O(n)_ | _O(1)_ | Medium |🔒| Sliding Window
1156 | [Swap For Longest Repeated Character Substring](https://leetcode.com/problems/swap-for-longest-repeated-character-substring/) | [C++](./C++/swap-for-longest-repeated-character-substring.cpp) [Python](./Python/swap-for-longest-repeated-character-substring.py) | _O(n)_ | _O(1)_ | Medium | | Sliding Window
1176 | [Diet Plan Performance](https://leetcode.com/problems/diet-plan-performance/) | [C++](./C++/diet-plan-performance.cpp) [Python](./Python/diet-plan-performance.py) | _O(n)_ | _O(1)_      | Easy         || Sliding Window
1208 | [Get Equal Substrings Within Budget](https://leetcode.com/problems/get-equal-substrings-within-budget/) | [C++](./C++/get-equal-substrings-within-budget.cpp) [Python](./Python/get-equal-substrings-within-budget.py) | _O(n)_ | _O(1)_      | Medium         || Sliding Window
1213 | [Intersection of Three Sorted Arrays](https://leetcode.com/problems/intersection-of-three-sorted-arrays/) | [C++](./C++/intersection-of-three-sorted-arrays.cpp) [Python](./Python/intersection-of-three-sorted-arrays.py) | _O(n)_ | _O(1)_      | Easy         |🔒|
1169 | [Invalid Transactions](https://leetcode.com/problems/invalid-transactions/) | [C++](./C++/invalid-transactions.cpp) [Python](./Python/invalid-transactions.py) | _O(nlogn)_ | _O(n)_      | Medium         || Sliding Window, Line Sweep
1214 | [Two Sum BSTs](https://leetcode.com/problems/two-sum-bsts/) | [C++](./C++/two-sum-bsts.cpp) [Python](./Python/two-sum-bsts.py) | _O(n)_ | _O(n)_      | Medium         |🔒| Stack |
1234 | [Replace the Substring for Balanced String](https://leetcode.com/problems/replace-the-substring-for-balanced-string/) | [C++](./C++/replace-the-substring-for-balanced-string.cpp) [Python](./Python/replace-the-substring-for-balanced-string.py) | _O(n)_ | _O(t)_ | Medium | | Two Pointers, Sliding Window
1248 | [Count Number of Nice Subarrays](https://leetcode.com/problems/count-number-of-nice-subarrays/) |[C++](./C++/count-number-of-nice-subarrays.cpp)  [Python](./Python/count-number-of-nice-subarrays.py) | _O(n)_ | _O(k)_ | Medium         | variant of [Subarrays with K Different Integers](https://leetcode.com/problems/subarrays-with-k-different-integers/) | Two Pointers, Sliding Window
1297 | [Maximum Number of Occurrences of a Substring](https://leetcode.com/problems/maximum-number-of-occurrences-of-a-substring/) | [C++](./C++/maximum-number-of-occurrences-of-a-substring.cpp) [Python](./Python/maximum-number-of-occurrences-of-a-substring.py) | _O(n)_ | _O(n)_ | Medium | | Sliding Window, `Rabin-Karp Algorithm`
1305 | [All Elements in Two Binary Search Trees](https://leetcode.com/problems/all-elements-in-two-binary-search-trees/)| [C++](./C++/all-elements-in-two-binary-search-trees.cpp)  [Python](./Python/all-elements-in-two-binary-search-trees.py) | _O(n)_ | _O(h)_ | Medium || Stack |
1316 | [Distinct Echo Substrings](https://leetcode.com/problems/distinct-echo-substrings/) | [C++](./C++/distinct-echo-substrings.cpp) [Python](./Python/distinct-echo-substrings.py) | _O(n^2 + d)_ | _O(r)_      | Hard         || `KMP Algorithm`, Sliding Window, `Rabin-Karp Algorithm`
1358 | [Number of Substrings Containing All Three Characters](https://leetcode.com/problems/number-of-substrings-containing-all-three-characters/) | [C++](./C++/number-of-substrings-containing-all-three-characters.cpp) [Python](./Python/number-of-substrings-containing-all-three-characters.py) | _O(n)_ | _O(1)_ | Medium | | Sliding Window
1423 | [Maximum Points You Can Obtain from Cards](https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards/) | [C++](./C++/maximum-points-you-can-obtain-from-cards.cpp) [Python](./Python/maximum-points-you-can-obtain-from-cards.py) | _O(n)_ | _O(1)_      | Medium         || Sliding Window
1425 | [Constrained Subset Sum](https://leetcode.com/problems/constrained-subset-sum/)| [C++](./C++/constrained-subset-sum.cpp) [Python](./Python/constrained-subset-sum.py) | _O(n)_        | _O(k)_          | Hard           | variant of [Sliding Window Maximum](https://leetcode.com/problems/sliding-window-maximum/) | Mono Deque, Sliding Window |
1456 | [Maximum Number of Vowels in a Substring of Given Length](https://leetcode.com/problems/maximum-number-of-vowels-in-a-substring-of-given-length/) | [C++](./C++/maximum-number-of-vowels-in-a-substring-of-given-length.cpp) [Python](./Python/maximum-number-of-vowels-in-a-substring-of-given-length.py) | _O(n)_ | _O(1)_ | Medium || Sliding Window |
1493 | [Longest Subarray of 1's After Deleting One Element](https://leetcode.com/problems/longest-subarray-of-1s-after-deleting-one-element/) | [C++](./C++/longest-subarray-of-1s-after-deleting-one-element.cpp) [Python](./Python/longest-subarray-of-1s-after-deleting-one-element.py) | _O(n)_ | _O(1)_ |  Medium | | Sliding Window
1498 | [Number of Subsequences That Satisfy the Given Sum Condition](https://leetcode.com/problems//number-of-subsequences-that-satisfy-the-given-sum-condition/)| [C++](./C++//number-of-subsequences-that-satisfy-the-given-sum-condition.cpp)  [Python](./Python//number-of-subsequences-that-satisfy-the-given-sum-condition.py) | _O(nlogn)_ | _O(n)_ | Medium || Two Pointers |
1508 | [Range Sum of Sorted Subarray Sums](https://leetcode.com/problems/range-sum-of-sorted-subarray-sums/) |[C++](./C++/range-sum-of-sorted-subarray-sums.cpp)  [Python](./Python/range-sum-of-sorted-subarray-sums.py) | _O(nlog(sum(nums)))_ | _O(n)_ | Medium         | | Binary Search, Two Pointers, Sliding Window
1521 | [Find a Value of a Mysterious Function Closest to Target](https://leetcode.com/problems/find-a-value-of-a-mysterious-function-closest-to-target/)| [C++](./C++/find-a-value-of-a-mysterious-function-closest-to-target.cpp) [Python](./Python/find-a-value-of-a-mysterious-function-closest-to-target.py) | _O(nlogm)_    | _O(logm)_          | Hard           || DP, Two Pointers, Sliding Window
1604 | [Alert Using Same Key-Card Three or More Times in a One Hour Period](https://leetcode.com/problems/alert-using-same-key-card-three-or-more-times-in-a-one-hour-period/) | [C++](./C++/alert-using-same-key-card-three-or-more-times-in-a-one-hour-period.cpp) [Python](./Python/alert-using-same-key-card-three-or-more-times-in-a-one-hour-period.py) | _O(nlogn)_ | _O(n)_ | Medium | | Two Pointers, Sliding Window |
1658 | [Minimum Operations to Reduce X to Zero](https://leetcode.com/problems/minimum-operations-to-reduce-x-to-zero/) | [C++](./C++/minimum-operations-to-reduce-x-to-zero.cpp) [Python](./Python/minimum-operations-to-reduce-x-to-zero.py) | _O(n)_ | _O(1)_ |  Medium | | Two Pointers |
1687 | [Delivering Boxes from Storage to Ports](https://leetcode.com/problems/delivering-boxes-from-storage-to-ports/) | [C++](./C++/delivering-boxes-from-storage-to-ports.cpp) [Python](./Python/delivering-boxes-from-storage-to-ports.py) | _O(nlogn)_ | _O(n)_ | Hard | | Two Pointers, Sliding Window |
1695 | [Maximum Erasure Value](https://leetcode.com/problems/maximum-erasure-value/) | [C++](./C++/maximum-erasure-value.cpp) [Python](./Python/maximum-erasure-value.py) | _O(n)_ | _O(n)_ | Medium | | Two Pointers, Sliding Window |
1712 | [Ways to Split Array Into Three Subarrays](https://leetcode.com/problems/ways-to-split-array-into-three-subarrays/) | [C++](./C++/ways-to-split-array-into-three-subarrays.cpp) [Python](./Python/ways-to-split-array-into-three-subarrays.py) | _O(n)_ | _O(n)_ | Medium | | Two Pointers, Prefix Sum |
1750 | [Minimum Length of String After Deleting Similar Ends](https://leetcode.com/problems/minimum-length-of-string-after-deleting-similar-ends/) | [C++](./C++/minimum-length-of-string-after-deleting-similar-ends.cpp) [Python](./Python/minimum-length-of-string-after-deleting-similar-ends.py) | _O(n)_ | _O(1)_ | Medium | | Two Pointers |
1838 | [Frequency of the Most Frequent Element](https://leetcode.com/problems/frequency-of-the-most-frequent-element/) | [C++](./C++/frequency-of-the-most-frequent-element.cpp) [Python](./Python/frequency-of-the-most-frequent-element.py) | _O(nlogn)_ | _O(n)_ | Medium | | Two Pointers, Sliding Window |
1852 | [Distinct Numbers in Each Subarray](https://leetcode.com/problems/distinct-numbers-in-each-subarray/) | [C++](./C++/distinct-numbers-in-each-subarray.cpp) [Python](./Python/distinct-numbers-in-each-subarray.py) | _O(n)_ | _O(k)_ | Medium | 🔒 | Two Pointers, Sliding Window |
1855 | [Maximum Distance Between a Pair of Values](https://leetcode.com/problems/maximum-distance-between-a-pair-of-values/) | [C++](./C++/maximum-distance-between-a-pair-of-values.cpp) [Python](./Python/maximum-distance-between-a-pair-of-values.py) | _O(n + m)_ | _O(1)_ | Medium | | Two Pointers |
1868 | [Product of Two Run-Length Encoded Arrays](https://leetcode.com/problems/product-of-two-run-length-encoded-arrays/) | [C++](./C++/product-of-two-run-length-encoded-arrays.cpp) [Python](./Python/product-of-two-run-length-encoded-arrays.py) | _O(m + n)_ | _O(1)_ | Medium | 🔒 | Two Pointers |
1885 | [Count Pairs in Two Arrays](https://leetcode.com/problems/count-pairs-in-two-arrays/) | [C++](./C++/count-pairs-in-two-arrays.cpp) [Python](./Python/count-pairs-in-two-arrays.py) | _O(nlogn)_ | _O(1)_ | Medium | 🔒 | Two Pointers |
1888 | [Minimum Number of Flips to Make the Binary String Alternatings](https://leetcode.com/problems/minimum-number-of-flips-to-make-the-binary-string-alternating/) | [C++](./C++/minimum-number-of-flips-to-make-the-binary-string-alternating.cpp) [Python](./Python/minimum-number-of-flips-to-make-the-binary-string-alternating.py) | _O(n)_ | _O(1)_ | Medium | | Two Pointers, Sliding Window |
1984 | [Minimum Difference Between Highest and Lowest of K Scores](https://leetcode.com/problems/minimum-difference-between-highest-and-lowest-of-k-scores/) | [C++](./C++/minimum-difference-between-highest-and-lowest-of-k-scores.cpp) [Python](./Python/minimum-difference-between-highest-and-lowest-of-k-scores.py) | _O(nlogn)_ | _O(1)_ | Easy | | Two Pointers, Sliding Window |
1989 | [Maximum Number of People That Can Be Caught in Tag](https://leetcode.com/problems/maximum-number-of-people-that-can-be-caught-in-tag/) | [C++](./C++/maximum-number-of-people-that-can-be-caught-in-tag.cpp) [Python](./Python/maximum-number-of-people-that-can-be-caught-in-tag.py) | _O(n)_ | _O(1)_ | Medium | 🔒 | Greedy, Two Pointers, Sliding Window
2009 | [Minimum Number of Operations to Make Array Continuous](https://leetcode.com/problems/minimum-number-of-operations-to-make-array-continuous/) | [C++](./C++/minimum-number-of-operations-to-make-array-continuous.cpp) [Python](./Python/minimum-number-of-operations-to-make-array-continuous.py) | _O(nlogn)_ | _O(1)_ | Hard || Two Pointers, Sliding Window
2024 | [Maximize the Confusion of an Exam](https://leetcode.com/problems/maximize-the-confusion-of-an-exam/) | [C++](./C++/maximize-the-confusion-of-an-exam.cpp) [Python](./Python/maximize-the-confusion-of-an-exam.py) | _O(n)_| _O(1)_| Medium | variant of [Longest Repeating Character Replacement](https://leetcode.com/problems/longest-repeating-character-replacement/) | Sliding Window |
2040 | [Kth Smallest Product of Two Sorted Arrays](https://leetcode.com/problems/kth-smallest-product-of-two-sorted-arrays/) | [C++](./C++/kth-smallest-product-of-two-sorted-arrays.cpp) [Python](./Python/kth-smallest-product-of-two-sorted-arrays.py) | _O((m + n) * logr)_| _O(1)_| Hard | | Binary Search, Two Pointers |
2046 | [Sort Linked List Already Sorted Using Absolute Values](https://leetcode.com/problems/sort-linked-list-already-sorted-using-absolute-values/)| [C++](./C++/sort-linked-list-already-sorted-using-absolute-values.cpp)  [Python](./Python/sort-linked-list-already-sorted-using-absolute-values.py) | _O(n)_ | _O(1)_         | Medium           | 🔒 | Linked List
2062 | [Count Vowel Substrings of a String](https://leetcode.com/problems/count-vowel-substrings-of-a-string/) | [C++](./C++/count-vowel-substrings-of-a-string.cpp) [Python](./Python/count-vowel-substrings-of-a-string.py) | _O(n)_ | _O(1)_ | Easy | variant of [Count Number of Nice Subarrays](https://leetcode.com/problems/count-number-of-nice-subarrays/) | Sliding Window
2067 | [Number of Equal Count Substrings](https://leetcode.com/problems/number-of-equal-count-substrings/) | [C++](./C++/number-of-equal-count-substrings.cpp) [Python](./Python/number-of-equal-count-substrings.py) | _O(n)_ | _O(1)_ | Medium | 🔒 | Sliding Window
2090 | [K Radius Subarray Averages](https://leetcode.com/problems/k-radius-subarray-averages/) | [C++](./C++/k-radius-subarray-averages.cpp) [Python](./Python/k-radius-subarray-averages.py) | _O(n)_ | _O(1)_ | Medium || Sliding Window
2105 | [Watering Plants II](https://leetcode.com/problems/watering-plants-ii/) | [C++](./C++/watering-plants-ii.cpp) [Python](./Python/watering-plants-ii.py) | _O(n)_ | _O(1)_ | Medium || Simulation
2107 | [Number of Unique Flavors After Sharing K Candies](https://leetcode.com/problems/number-of-unique-flavors-after-sharing-k-candies/) | [C++](./C++/number-of-unique-flavors-after-sharing-k-candies.cpp) [Python](./Python/number-of-unique-flavors-after-sharing-k-candies.py) | _O(n)_ | _O(n)_ | Medium | 🔒 | Sliding Window
2134 | [Minimum Swaps to Group All 1's Together II](https://leetcode.com/problems/minimum-swaps-to-group-all-1s-together-ii/) | [C++](./C++/minimum-swaps-to-group-all-1s-together-ii.cpp) [Python](./Python/minimum-swaps-to-group-all-1s-together-ii.py) | _O(n)_ | _O(1)_ | Medium | | Sliding Window
2149 | [Rearrange Array Elements by Sign](https://leetcode.com/problems/rearrange-array-elements-by-sign/) | [C++](./C++/rearrange-array-elements-by-sign.cpp) [Python](./Python/rearrange-array-elements-by-sign.py) | _O(n)_ | _O(1)_ | Medium | | Two Pointers

<br/>
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<br/>

## Recursion
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1106 | [Parsing A Boolean Expression](https://leetcode.com/problems/parsing-a-boolean-expression/) | [C++](./C++/parsing-a-boolean-expression.cpp) [Python](./Python/parsing-a-boolean-expression.py) | _O(n)_          | _O(n)_          | Hard           ||

<br/>
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</div>
<br/>

## Binary Search
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1011 | [Capacity To Ship Packages Within D Days](https://leetcode.com/problems/capacity-to-ship-packages-within-d-days/) | [C++](./C++/capacity-to-ship-packages-within-d-days.cpp) [Python](./Python/capacity-to-ship-packages-within-d-days.py) | _O(nlogr)_ | _O(1)_ | Medium | |
1044 | [Longest Duplicate Substring](https://leetcode.com/problems/longest-duplicate-substring/) | [C++](./C++/longest-duplicate-substring.cpp) [Python](./Python/longest-duplicate-substring.py) | _O(nlogn)_ | _O(n)_ | Hard | | `Rabin-Karp Algorithm`, Suffix Tree, `Ukkonen's Algorithm`
1060 | [Missing Element in Sorted Array](https://leetcode.com/problems/missing-element-in-sorted-array/)| [C++](./C++/missing-element-in-sorted-array.cpp)  [Python](./Python/missing-element-in-sorted-array.py) | _O(logn)_ | _O(1)_ | Medium |🔒| |
1062 | [Longest Repeating Substring](https://leetcode.com/problems/longest-repeating-substring/) | [C++](./C++/longest-repeating-substring.cpp) [Python](./Python/longest-repeating-substring.py) | _O(nlogn)_ | _O(n)_ | Medium |🔒| `Rabin-Karp Algorithm`
1064 | [Fixed Point](https://leetcode.com/problems/fixed-point/)| [C++](./C++/fixed-point.cpp)  [Python](./Python/fixed-point.py) | _O(logn)_ | _O(1)_ | Easy |🔒| |
1095 | [Find in Mountain Array](https://leetcode.com/problems/find-in-mountain-array/)| [C++](./C++/find-in-mountain-array.cpp)  [Python](./Python/find-in-mountain-array.py) | _O(logn)_ | _O(1)_ | Hard | | |
1110 | [Delete Nodes And Return Forest](https://leetcode.com/problems/delete-nodes-and-return-forest/) | [C++](./C++/delete-nodes-and-return-forest.cpp) [Python](./Python/delete-nodes-and-return-forest.py) | _O(n)_ | _O(h + d)_ | Medium | |
1170 | [Compare Strings by Frequency of the Smallest Character](https://leetcode.com/problems/compare-strings-by-frequency-of-the-smallest-character/) | [C++](./C++/compare-strings-by-frequency-of-the-smallest-character.cpp) [Python](./Python/compare-strings-by-frequency-of-the-smallest-character.py) | _O((m + n)logn)_ | _O(n)_ | Easy | |
1201 | [Ugly Number III](https://leetcode.com/problems/ugly-number-iii/) | [C++](./C++/ugly-number-iii.cpp) [Python](./Python/ugly-number-iii.py) | _O(logn)_ | _O(1)_ | Medium | | Inclusion-Exclusion Principle
1228 | [Missing Number In Arithmetic Progression](https://leetcode.com/problems/missing-number-in-arithmetic-progression/) | [C++](./C++/missing-number-in-arithmetic-progression.cpp) [Python](./Python/missing-number-in-arithmetic-progression.py) | _O(logn)_ | _O(1)_ | Easy | |
1231 | [Divide Chocolate](https://leetcode.com/problems/divide-chocolate/) | [C++](./C++/divide-chocolate.cpp) [Python](./Python/divide-chocolate.py) | _O(nlogn)_ | _O(1)_ | Hard | |
1274 | [Number of Ships in a Rectangle](https://leetcode.com/problems/number-of-ships-in-a-rectangle/) | [C++](./C++/number-of-ships-in-a-rectangle.cpp) [Python](./Python/number-of-ships-in-a-rectangle.py) | _O(log(m * n))_ | _O(log(m * n))_ | Hard | | Divide and Conquer
1283 | [Find the Smallest Divisor Given a Threshold](https://leetcode.com/problems/find-the-smallest-divisor-given-a-threshold/) | [C++](./C++/find-the-smallest-divisor-given-a-threshold.cpp) [Python](./Python/find-the-smallest-divisor-given-a-threshold.py) | _O(logn)_ | _O(1)_ | Medium | |
1287 | [Element Appearing More Than 25% In Sorted Array](https://leetcode.com/problems/element-appearing-more-than-25-in-sorted-array/) | [C++](./C++/element-appearing-more-than-25-in-sorted-array.cpp) [Python](./Python/element-appearing-more-than-25-in-sorted-array.py) | _O(logn)_ | _O(1)_ | Easy | |
1385 | [Find the Distance Value Between Two Arrays](https://leetcode.com/problems/find-the-distance-value-between-two-arrays/) | [C++](./C++/find-the-distance-value-between-two-arrays.cpp) [Python](./Python/find-the-distance-value-between-two-arrays.py) | _O((n + m) * logm)_ | _O(1)_ | Easy | | Binary Search, Two Pointers
1482 | [Minimum Number of Days to Make m Bouquets](https://leetcode.com/problems/minimum-number-of-days-to-make-m-bouquets/) | [C++](./C++/minimum-number-of-days-to-make-m-bouquets.cpp) [Python](./Python/minimum-number-of-days-to-make-m-bouquets.py) | _O(nlogd)_ | _O(1)_ | Medium | |
1533 | [Find the Index of the Large Integer](https://leetcode.com/problems/find-the-index-of-the-large-integer/) | [C++](./C++/find-the-index-of-the-large-integer.cpp) [Python](./Python/find-the-index-of-the-large-integer.py) | _O(logn)_ | _O(1)_ | Medium | 🔒 |
1539 | [Kth Missing Positive Number](https://leetcode.com/problems/kth-missing-positive-number/) | [C++](./C++/kth-missing-positive-number.cpp) [Python](./Python/kth-missing-positive-number.py) | _O(logn)_ | _O(1)_ | Easy | |
1552 | [Magnetic Force Between Two Balls](https://leetcode.com/problems/magnetic-force-between-two-balls/) | [C++](./C++/magnetic-force-between-two-balls.cpp) [Python](./Python/magnetic-force-between-two-balls.py) | _O(nlogn + nlogr)_ | _O(1)_ | Medium | |
1618 | [Maximum Font to Fit a Sentence in a Screen](https://leetcode.com/problems/maximum-font-to-fit-a-sentence-in-a-screen/) | [C++](./C++/maximum-font-to-fit-a-sentence-in-a-screen.cpp) [Python](./Python/maximum-font-to-fit-a-sentence-in-a-screen.py) | _O(n + logm)_ | _O(1)_ | Medium |🔒|
1648 | [Sell Diminishing-Valued Colored Balls](https://leetcode.com/problems/sell-diminishing-valued-colored-balls/) | [C++](./C++/sell-diminishing-valued-colored-balls.cpp) [Python](./Python/sell-diminishing-valued-colored-balls.py) | _O(nlogm)_ | _O(1)_ | Medium | |
1671 | [Minimum Number of Removals to Make Mountain Array](https://leetcode.com/problems/minimum-number-of-removals-to-make-mountain-array/) | [C++](./C++/minimum-number-of-removals-to-make-mountain-array.cpp)  [Python](./Python/minimum-number-of-removals-to-make-mountain-array.py)  | _O(nlogn)_ | _O(n)_ | Medium         | variant of [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | Binary Search, DP|
1713 | [Minimum Operations to Make a Subsequence](https://leetcode.com/problems/minimum-operations-to-make-a-subsequence/) | [C++](./C++/minimum-operations-to-make-a-subsequence.cpp)  [Python](./Python/minimum-operations-to-make-a-subsequence.py)  | _O(nlogn)_ | _O(n)_ | Hard         | variant of [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | Binary Search, Segment Tree |
1760 | [Minimum Limit of Balls in a Bag](https://leetcode.com/problems/minimum-limit-of-balls-in-a-bag/) | [C++](./C++/minimum-limit-of-balls-in-a-bag.cpp) [Python](./Python/minimum-limit-of-balls-in-a-bag.py) | _O(nlogm)_ | _O(1)_ | Medium | |
1802 | [Maximum Value at a Given Index in a Bounded Array](https://leetcode.com/problems/maximum-value-at-a-given-index-in-a-bounded-array/) | [C++](./C++/maximum-value-at-a-given-index-in-a-bounded-array.cpp) [Python](./Python/maximum-value-at-a-given-index-in-a-bounded-array.py) | _O(logm)_ | _O(1)_ | Medium | |
1818 | [Minimum Absolute Sum Difference](https://leetcode.com/problems/minimum-absolute-sum-difference/) | [C++](./C++/minimum-absolute-sum-difference.cpp) [Python](./Python/minimum-absolute-sum-difference.py) | _O(nlogn)_ | _O(n)_ | Medium | |
1870 | [Minimum Speed to Arrive on Time](https://leetcode.com/problems/minimum-speed-to-arrive-on-time/) | [C++](./C++/minimum-speed-to-arrive-on-time.cpp) [Python](./Python/minimum-speed-to-arrive-on-time.py) | _O(nlogr)_ | _O(1)_ | Medium | |
1889 | [Minimum Space Wasted From Packaging](https://leetcode.com/problems/minimum-space-wasted-from-packaging/) | [C++](./C++/minimum-space-wasted-from-packaging.cpp) [Python](./Python/minimum-space-wasted-from-packaging.py) | _O(mlogm + nlogn + mlogn)_ | _O(1)_ | Hard | |
1891 | [Cutting Ribbons](https://leetcode.com/problems/cutting-ribbons/) | [C++](./C++/cutting-ribbons.cpp) [Python](./Python/cutting-ribbons.py) | _O(nlogr)_ | _O(1)_ | Medium | 🔒 |
1898 | [Maximum Number of Removable Characters](https://leetcode.com/problems/maximum-number-of-removable-characters/) | [C++](./C++/maximum-number-of-removable-characters.cpp) [Python](./Python/maximum-number-of-removable-characters.py) | _O(rlogn)_ | _O(r)_ | Medium | |
1901 | [Find a Peak Element II](https://leetcode.com/problems/find-a-peak-element-ii/) | [C++](./C++/find-a-peak-element-ii.cpp) [Python](./Python/find-a-peak-element-ii.py) | _O(min(n, m) * log(max(n, m)))_ | _O(1)_ | Medium | |
1918 | [Kth Smallest Subarray Sum](https://leetcode.com/problems/kth-smallest-subarray-sum/) | [C++](./C++/kth-smallest-subarray-sum.cpp) [Python](./Python/kth-smallest-subarray-sum.py) | _O(nlogr)_ | _O(1)_ | Medium | 🔒 |
1964 | [Find the Longest Valid Obstacle Course at Each Position](https://leetcode.com/problems/find-the-longest-valid-obstacle-course-at-each-position/) | [C++](./C++/find-the-longest-valid-obstacle-course-at-each-position.cpp)  [Python](./Python/find-the-longest-valid-obstacle-course-at-each-position.py)  | _O(nlogn)_ | _O(n)_ | Hard         | variant of [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | Binary Search, Segment Tree, DP|
2064 | [Minimized Maximum of Products Distributed to Any Store](https://leetcode.com/problems/minimized-maximum-of-products-distributed-to-any-store/) | [C++](./C++/minimized-maximum-of-products-distributed-to-any-store.cpp) [Python](./Python/minimized-maximum-of-products-distributed-to-any-store.py) | _O(nlogm)_ | _O(1)_ | Medium | variant of [Minimum Limit of Balls in a Bag](https://leetcode.com/problems/minimum-limit-of-balls-in-a-bag/) |
2111 | [Minimum Operations to Make the Array K-Increasing](https://leetcode.com/problems/minimum-operations-to-make-the-array-k-increasing/) | [C++](./C++/minimum-operations-to-make-the-array-k-increasing.cpp) [Python](./Python/minimum-operations-to-make-the-array-k-increasing.py) | _O(nlog(n/k))_ | _O(n/k)_ | Hard | variant of [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) |
2137 | [Pour Water Between Buckets to Make Water Levels Equal](https://leetcode.com/problems/pour-water-between-buckets-to-make-water-levels-equal/) | [C++](./C++/pour-water-between-buckets-to-make-water-levels-equal.cpp) [Python](./Python/pour-water-between-buckets-to-make-water-levels-equal.py) | _O(nlogr)_ | _O(1)_ | Medium | 🔒 |

<br/>
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<br/>

## Binary Search Tree
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1373 | [Maximum Sum BST in Binary Tree](https://leetcode.com/problems/maximum-sum-bst-in-binary-tree/) | [C++](./C++/maximum-sum-bst-in-binary-tree.cpp) [Python](./Python/maximum-sum-bst-in-binary-tree.py) | _O(n)_          | _O(h)_          | Hard           || DFS, Stack |
1382 | [Balance a Binary Search Tree](https://leetcode.com/problems/balance-a-binary-search-tree/) | [C++](./C++/balance-a-binary-search-tree.cpp) [Python](./Python/balance-a-binary-search-tree.py) | _O(n)_          | _O(h)_          | Medium           || DFS, Stack |
1902 | [Depth of BST Given Insertion Order](https://depth-of-bst-given-insertion-order/)| [C++](./C++/depth-of-bst-given-insertion-order.cpp) [Python](./Python/depth-of-bst-given-insertion-order.py)   | _O(nlogn)_          | _O(n)_          | Medium         | 🔒 | Sorted Dict |
1932 | [Merge BSTs to Create Single BST](https://leetcode.com/problems/merge-bsts-to-create-single-bst/)|[C++](./C++/merge-bsts-to-create-single-bst.cpp) [Python](./Python/merge-bsts-to-create-single-bst.py) | _O(n)_      | _O(n)_          | Hard         | | BST, BFS

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<br/>

## Breadth-First Search
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1034 | [Coloring A Border](https://leetcode.com/problems/coloring-a-border/)| [C++](./C++/coloring-a-border.cpp) [Python](./Python/coloring-a-border.py)| _O(m * n)_ | _O(m + n)_ | Medium | | |
1036 | [Escape a Large Maze](https://leetcode.com/problems/escape-a-large-maze/)| [C++](./C++/escape-a-large-maze.cpp) [Python](./Python/escape-a-large-maze.py)| _O(n^2)_ | _O(n)_ | Hard | | |
1091 | [Shortest Path in Binary Matrix](https://leetcode.com/problems/shortest-path-in-binary-matrix/)| [C++](./C++/shortest-path-in-binary-matrix.cpp) [Python](./Python/shortest-path-in-binary-matrix.py)| _O(n^2)_ | _O(n)_ | Medium | | |
1102 | [Path With Maximum Minimum Value](https://leetcode.com/problems/path-with-maximum-minimum-value/)| [C++](./C++/path-with-maximum-minimum-value.cpp) [Python](./Python/path-with-maximum-minimum-value.py)| _O((m * n) * log(m * n))_ | _O(m * n)_ | Medium | 🔒 | Binary Search, DFS, `Dijkstra's Algorithm` |
1129 | [Shortest Path with Alternating Colors](https://leetcode.com/problems/shortest-path-with-alternating-colors/)| [C++](./C++/shortest-path-with-alternating-colors.cpp) [Python](./Python/shortest-path-with-alternating-colors.py)| _O(n + e)_ | _O(n + e)_ | Medium |||
1136 | [Parallel Courses](https://leetcode.com/problems/parallel-courses/)| [C++](./C++/parallel-courses.cpp) [Python](./Python/parallel-courses.py)   | _O(\|V\| + \|E\|)_         | _O(\|E\|)_          | Hard         |🔒| Topological Sort |
1161 | [Maximum Level Sum of a Binary Tree](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree/)| [C++](./C++/maximum-level-sum-of-a-binary-tree.cpp) [Python](./Python/maximum-level-sum-of-a-binary-tree.py)| _O(n)_ | _O(w)_ | Medium | | DFS |
1162 | [As Far from Land as Possible](https://leetcode.com/problems/as-far-from-land-as-possible/)| [C++](./C++/as-far-from-land-as-possible.cpp) [Python](./Python/as-far-from-land-as-possible.py)| _O(m * n)_ | _O(m * n)_ | Medium | | |
1203 | [Sort Items by Groups Respecting Dependencies](https://leetcode.com/problems/sort-items-by-groups-respecting-dependencies/)| [C++](./C++/sort-items-by-groups-respecting-dependencies.cpp) [Python](./Python/sort-items-by-groups-respecting-dependencies.py)   | _O(n + e)_          | _O(n + e)_          | Hard         || Topological Sort |
1210 | [Minimum Moves to Reach Target with Rotations](https://leetcode.com/problems/minimum-moves-to-reach-target-with-rotations/)| [C++](./C++/minimum-moves-to-reach-target-with-rotations.cpp) [Python](./Python/minimum-moves-to-reach-target-with-rotations.py)   | _O(n)_          | _O(n)_          | Hard         |||
1215 | [Stepping Numbers](https://leetcode.com/problems/stepping-numbers/)| [C++](./C++/stepping-numbers.cpp) [Python](./Python/stepping-numbers.py)   | _O(logk + r)_          | _O(k)_          | Medium         |🔒| Precompute, Binary Search |
1245 | [Tree Diameter](https://leetcode.com/problems/tree-diameter/)| [C++](./C++/tree-diameter.cpp) [Python](./Python/tree-diameter.py)   | _O(\|V\| + \|E\|)_         | _O(\|E\|)_          | Medium         |||
1263 | [Minimum Moves to Move a Box to Their Target Location](https://leetcode.com/problems/minimum-moves-to-move-a-box-to-their-target-location/)| [C++](./C++/minimum-moves-to-move-a-box-to-their-target-location.cpp) [Python](./Python/minimum-moves-to-move-a-box-to-their-target-location.py)| _O(m^2 * n^2)_ | _O(m^2 * n^2)_ | Hard | | `A* Search Algorithm` |
1284 | [Minimum Number of Flips to Convert Binary Matrix to Zero Matrix](https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix/)| [C++](./C++/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix.cpp) [Python](./Python/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix.py)   | _O((m * n) * 2^(m * n))_         | _O((m * n) * 2^(m * n))_          | Hard         |||
1291 | [Sequential Digits](https://leetcode.com/problems/sequential-digits/)| [C++](./C++/sequential-digits.cpp) [Python](./Python/sequential-digits.py)| _O(1)_ | _O(1)_ | Medium | | |
1293 | [Shortest Path in a Grid with Obstacles Elimination](https://leetcode.com/problems/shortest-path-in-a-grid-with-obstacles-elimination/)| [C++](./C++/shortest-path-in-a-grid-with-obstacles-elimination.cpp) [Python](./Python/shortest-path-in-a-grid-with-obstacles-elimination.py)| _O(m * n * k)_ | _O(m * n)_ | Hard | | `A* Search Algorithm` |
1298 | [Maximum Candies You Can Get from Boxes](https://leetcode.com/problems/maximum-candies-you-can-get-from-boxes/)| [C++](./C++/maximum-candies-you-can-get-from-boxes.cpp) [Python](./Python/maximum-candies-you-can-get-from-boxes.py)| _O(n^2)_ | _O(n)_ | Hard | | |
1302 | [Deepest Leaves Sum](https://leetcode.com/problems/deepest-leaves-sum/)| [C++](./C++/deepest-leaves-sum.cpp) [Python](./Python/deepest-leaves-sum.py)| _O(n)_ | _O(w)_ | Medium | | |
1306 | [Jump Game III](https://leetcode.com/problems/jump-game-iii/)| [C++](./C++/jump-game-iii.cpp) [Python](./Python/jump-game-iii.py)| _O(n)_ | _O(n)_ | Medium | | |
1311 | [Get Watched Videos by Your Friends](https://leetcode.com/problems/get-watched-videos-by-your-friends/)| [C++](./C++/get-watched-videos-by-your-friends.cpp) [Python](./Python/get-watched-videos-by-your-friends.py)| _O(n + vlogv)_ | _O(w)_ | Medium | | |
1345 | [Jump Game IV](https://leetcode.com/problems/jump-game-iv/)| [C++](./C++/jump-game-iv.cpp) [Python](./Python/jump-game-iv.py)| _O(n)_ | _O(n)_ | Hard | | |
1368 | [Minimum Cost to Make at Least One Valid Path in a Grid](https://leetcode.com/problems/minimum-cost-to-make-at-least-one-valid-path-in-a-grid/)| [C++](./C++/minimum-cost-to-make-at-least-one-valid-path-in-a-grid.cpp) [Python](./Python/minimum-cost-to-make-at-least-one-valid-path-in-a-grid.py)| _O(m * n)_ | _O(m * n)_ | Hard | | `A* Search Algorithm`, 0-1 BFS, Deque |
1514 | [Path with Maximum Probability](https://leetcode.com/problems/path-with-maximum-probability/)| [C++](./C++/path-with-maximum-probability.cpp) [Python](./Python/path-with-maximum-probability.py)| _O(\|E\| * log\|V\|)_ | _O(\|E\|)_ | Medium | | `Dijkstra's Algorithm` |
1602 | [Find Nearest Right Node in Binary Tree](https://leetcode.com/problems/find-nearest-right-node-in-binary-tree/)| [C++](./C++/find-nearest-right-node-in-binary-tree.cpp) [Python](./Python/find-nearest-right-node-in-binary-tree.py)| _O(n)_ | _O(w)_ | Medium |🔒| 
1609 | [Even Odd Tree](https://leetcode.com/problems/even-odd-tree/)| [C++](./C++/even-odd-tree.cpp) [Python](./Python/even-odd-tree.py)| _O(n)_ | _O(w)_ | Medium || 
1625 | [Lexicographically Smallest String After Applying Operations](https://leetcode.com/problems/lexicographically-smallest-string-after-applying-operations/)| [C++](./C++/lexicographically-smallest-string-after-applying-operations.cpp) [Python](./Python/lexicographically-smallest-string-after-applying-operations.py)| _O(n^2)_ | _O(1)_ | Medium || BFS, String 
1654 | [Minimum Jumps to Reach Home](https://leetcode.com/problems/minimum-jumps-to-reach-home/)| [C++](./C++/minimum-jumps-to-reach-home.cpp) [Python](./Python/minimum-jumps-to-reach-home.py)| _O(max(x, max(forbidden)) + a + b)_ | _O(max(x, max(forbidden)) + a + b)_ | Medium || BFS 
1660 | [Correct a Binary Tree](https://leetcode.com/problems/correct-a-binary-tree/)| [C++](./C++/correct-a-binary-tree.cpp) [Python](./Python/correct-a-binary-tree.py)| _O(n)_ | _O(w)_ | Medium |🔒| BFS 
1728 | [Cat and Mouse II](https://leetcode.com/problems/cat-and-mouse-ii/) | [C++](./C++/cat-and-mouse-ii.cpp) [Python](./Python/cat-and-mouse-ii.py) | _O((m * n)^2 * (m + n))_          | _O((m * n)^2)_          | Hard           | variant of [Cat and Mouse](https://leetcode.com/problems/cat-and-mouse/) | MiniMax, Topological Sort |
1730 | [Shortest Path to Get Food](https://leetcode.com/problems/shortest-path-to-get-food/)| [C++](./C++/shortest-path-to-get-food.cpp) [Python](./Python/shortest-path-to-get-food.py)| _O(m * n)_ | _O(m + n)_ | Medium |🔒| BFS 
1765 | [Map of Highest Peak](https://leetcode.com/problems/map-of-highest-peak/)| [C++](./C++/map-of-highest-peak.cpp) [Python](./Python/map-of-highest-peak.py)| _O(m * n)_ | _O(m * n)_ | Medium | | BFS 
1926 | [Nearest Exit from Entrance in Maze](https://leetcode.com/problems/nearest-exit-from-entrance-in-maze/)|[C++](./C++/nearest-exit-from-entrance-in-maze.cpp) [Python](./Python/nearest-exit-from-entrance-in-maze.py) | _O(m * n)_      | _O(m + n)_          | Medium         | | Bi-BFS
1928 | [Minimum Cost to Reach Destination in Time](https://leetcode.com/problems/minimum-cost-to-reach-destination-in-time/)| [C++](./C++/minimum-cost-to-reach-destination-in-time.cpp) [Python](./Python/minimum-cost-to-reach-destination-in-time.py)| _O(\|E\| * log\|V\|)_ | _O(\|E\|)_ | Hard | variant of [Cheapest Flights Within K Stops](https://leetcode.com/problems/cheapest-flights-within-k-stops/) | `Dijkstra's Algorithm` |
2039 | [The Time When the Network Becomes Idle](https://leetcode.com/problems/the-time-when-the-network-becomes-idle/)| [C++](./C++/the-time-when-the-network-becomes-idle.cpp) [Python](./Python/the-time-when-the-network-becomes-idle.py)| _O(\|E\|)_ | _O(\|E\|)_ | Medium | | Math |
2045 | [Second Minimum Time to Reach Destination](https://leetcode.com/problems/second-minimum-time-to-reach-destination/)| [C++](./C++/second-minimum-time-to-reach-destination.cpp) [Python](./Python/second-minimum-time-to-reach-destination.py)| _O(\|E\|)_ | _O(\|E\|)_ | Hard | | Bi-BFS |
2050 | [Parallel Courses III](https://leetcode.com/problems/parallel-courses-iii/)| [C++](./C++/parallel-courses-iii.cpp) [Python](./Python/parallel-courses-iii.py)   | _O(\|V\| + \|E\|)_         | _O(\|E\|)_          | Hard         | variant of [Parallel Courses](https://leetcode.com/problems/parallel-courses/) | Topological Sort |
2059 | [Minimum Operations to Convert Number](https://leetcode.com/problems/minimum-operations-to-convert-number/)| [C++](./C++/minimum-operations-to-convert-number.cpp) [Python](./Python/minimum-operations-to-convert-number.py)| _O(m * n)_ | _O(m)_ | Medium | | |
2115 | [Find All Possible Recipes from Given Supplies](https://leetcode.com/problems/find-all-possible-recipes-from-given-supplies/)| [C++](./C++/find-all-possible-recipes-from-given-supplies.cpp) [Python](./Python/find-all-possible-recipes-from-given-supplies.py)   | _O(\|E\|)_         | _O(\|E\|)_          | Medium         | | Topological Sort |
2146 | [K Highest Ranked Items Within a Price Range](https://leetcode.com/problems/k-highest-ranked-items-within-a-price-range/)| [C++](./C++/k-highest-ranked-items-within-a-price-range.cpp) [Python](./Python/k-highest-ranked-items-within-a-price-range.py)   | _O(m * n + klogk)_         | _O(m * n)_          | Medium         | | BFS, Quick Select, Sort |

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## Depth-First Search
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1020 | [Number of Enclaves](https://leetcode.com/problems/number-of-enclaves/) | [C++](./C++/number-of-enclaves.cpp) [Python](./Python/number-of-enclaves.py) | _O(m * n)_          | _O(m * n)_          | Medium           |||
1059 | [All Paths from Source Lead to Destination](https://leetcode.com/problems/all-paths-from-source-lead-to-destination/) | [C++](./C++/all-paths-from-source-lead-to-destination.cpp) [Python](./Python/all-paths-from-source-lead-to-destination.py) | _O(n + e)_          | _O(n + e)_          | Medium           |🔒||
1192 | [Critical Connections in a Network](https://leetcode.com/problems/critical-connections-in-a-network/) | [C++](./C++/critical-connections-in-a-network.cpp) [Python](./Python/critical-connections-in-a-network.py) | _O(\|V\| + \|E\|)_           | _O(\|V\| + \|E\|)_          | Hard           || `Tarjan's Algorithm`, `Bridge Finding Algorithm` |
1202 | [Smallest String With Swaps](https://leetcode.com/problems/smallest-string-with-swaps/) | [C++](./C++/smallest-string-with-swaps.cpp) [Python](./Python/smallest-string-with-swaps.py) | _O(nlogn)_          | _O(n)_          | Medium           || Union Find |
1254 | [Number of Closed Islands](https://leetcode.com/problems/number-of-closed-islands/) | [C++](./C++/number-of-closed-islands.cpp) [Python](./Python/number-of-closed-islands.py) | _O(m * n)_          | _O(1)_          | Medium           |||
1273 | [Delete Tree Nodes](https://leetcode.com/problems/delete-tree-nodes/) | [C++](./C++/delete-tree-nodes.cpp) [Python](./Python/delete-tree-nodes.py) | _O(n)_          | _O(n)_          | Medium           || DFS, DP |
1315 | [Sum of Nodes with Even-Valued Grandparent](https://leetcode.com/problems/sum-of-nodes-with-even-valued-grandparent/) | [C++](./C++/sum-of-nodes-with-even-valued-grandparent.cpp) [Python](./Python/sum-of-nodes-with-even-valued-grandparent.py) | _O(n)_          | _O(h)_          | Medium           |||
1319 | [Number of Operations to Make Network Connected](https://leetcode.com/problems/number-of-operations-to-make-network-connected/) | [C++](./C++/number-of-operations-to-make-network-connected.cpp) [Python](./Python/number-of-operations-to-make-network-connected.py) | _O(\|E\| + \|V\|)_          | _O(\|V\|)_          | Medium           || Union Find|
1367 | [Linked List in Binary Tree](https://leetcode.com/problems/linked-list-in-binary-tree/) | [C++](./C++/linked-list-in-binary-tree.cpp) [Python](./Python/linked-list-in-binary-tree.py) | _O(n + l)_          | _O(h + l)_          | Medium           || `KMP Algorithm` |
1372 | [Longest ZigZag Path in a Binary Tree](https://leetcode.com/problems/longest-zigzag-path-in-a-binary-tree/) | [C++](./C++/longest-zigzag-path-in-a-binary-tree.cpp) [Python](./Python/longest-zigzag-path-in-a-binary-tree.py) | _O(n)_          | _O(h)_          | Medium           |||
1376 | [Time Needed to Inform All Employees](https://leetcode.com/problems/time-needed-to-inform-all-employees/) | [C++](./C++/time-needed-to-inform-all-employees.cpp) [Python](./Python/time-needed-to-inform-all-employees.py) | _O(n)_          | _O(n)_          | Medium           |||
1377 | [Frog Position After T Seconds](https://leetcode.com/problems/frog-position-after-t-seconds/) | [C++](./C++/frog-position-after-t-seconds.cpp) [Python](./Python/frog-position-after-t-seconds.py) | _O(n)_          | _O(n)_          | Hard           || DFS, Stack, BFS|
1391 | [Check if There is a Valid Path in a Grid](https://leetcode.com/problems/check-if-there-is-a-valid-path-in-a-grid/) | [C++](./C++/check-if-there-is-a-valid-path-in-a-grid.cpp) [Python](./Python/check-if-there-is-a-valid-path-in-a-grid.py) | _O(m * n)_          | _O(1)_          | Medium           || Simulation |
1466 | [Reorder Routes to Make All Paths Lead to the City Zero](https://leetcode.com/problems/reorder-routes-to-make-all-paths-lead-to-the-city-zero/) | [C++](./C++/reorder-routes-to-make-all-paths-lead-to-the-city-zero.cpp) [Python](./Python/reorder-routes-to-make-all-paths-lead-to-the-city-zero.py) | _O(n)_          | _O(n)_          | Medium           || DFS, Stack |
1485 | [Clone Binary Tree With Random Pointer](https://leetcode.com/problems/clone-binary-tree-with-random-pointer/) | [C++](./C++/clone-binary-tree-with-random-pointer.cpp) [Python](./Python/clone-binary-tree-with-random-pointer.py) | _O(n)_          | _O(h)_          | Medium           |🔒| DFS, Stack |
1644 | [Lowest Common Ancestor of a Binary Tree II](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-ii/) | [C++](./C++/lowest-common-ancestor-of-a-binary-tree-ii.cpp) [Python](./Python/lowest-common-ancestor-of-a-binary-tree-ii.py) | _O(n)_          | _O(h)_          | Medium           |🔒| DFS, Stack |
1676 | [Lowest Common Ancestor of a Binary Tree IV](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree-iv/) | [C++](./C++/lowest-common-ancestor-of-a-binary-tree-iv.cpp) [Python](./Python/lowest-common-ancestor-of-a-binary-tree-iv.py) | _O(n)_          | _O(h)_          | Medium           |🔒| DFS, Stack |
1722 | [Minimize Hamming Distance After Swap Operations](https://leetcode.com/problems/minimize-hamming-distance-after-swap-operations/) | [C++](./C++/minimize-hamming-distance-after-swap-operations.cpp) [Python](./Python/minimize-hamming-distance-after-swap-operations.py) | _O(n)_          | _O(n)_          | Medium           || Flood Fill, Union Find |
1740 | [Find Distance in a Binary Tree](https://leetcode.com/problems/find-distance-in-a-binary-tree/) | [C++](./C++/find-distance-in-a-binary-tree.cpp) [Python](./Python/find-distance-in-a-binary-tree.py) | _O(n)_ | _O(h)_ | Medium | variant of [Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/), 🔒 | |
1766 | [Tree of Coprimes](https://leetcode.com/problems/tree-of-coprimes/) | [C++](./C++/tree-of-coprimes.cpp) [Python](./Python/tree-of-coprimes.py) | _O(n)_ | _O(n)_ | Hard | | |
1905 | [Count Sub Islands](https://leetcode.com/problems/count-sub-islands/) | [C++](./C++/count-sub-islands.cpp) [Python](./Python/count-sub-islands.py) | _O(m * n)_ | _O(1)_ | Medium | | Flood Fill |
1973 | [Count Nodes Equal to Sum of Descendants](https://leetcode.com/problems/count-nodes-equal-to-sum-of-descendants/) | [C++](./C++/count-nodes-equal-to-sum-of-descendants.cpp) [Python](./Python/count-nodes-equal-to-sum-of-descendants.py) | _O(n)_ | _O(h)_ | Medium | 🔒 | |
2049 | [Count Nodes With the Highest Score](https://leetcode.com/problems/count-nodes-with-the-highest-score/) | [C++](./C++/count-nodes-with-the-highest-score.cpp) [Python](./Python/count-nodes-with-the-highest-score.py) | _O(n)_ | _O(n)_ | Medium | | |
2065 | [Maximum Path Quality of a Graph](https://leetcode.com/problems/maximum-path-quality-of-a-graph/) | [C++](./C++/maximum-path-quality-of-a-graph.cpp) [Python](./Python/maximum-path-quality-of-a-graph.py) | _O(\|V\| + \|E\| + 4^10)_ | _O(\|V\| + \|E\| )_ | Hard | | Pruning |

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## Backtracking
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1087 | [Brace Expansion](https://leetcode.com/problems/brace-expansion/) | [C++](./C++/brace-expansion.cpp) [Python](./Python/brace-expansion.py)  | _O(p * l * log(p * l))_ | _O(p * l)_ | Medium         |🔒||
1096 | [Brace Expansion II](https://leetcode.com/problems/brace-expansion-ii/) | [C++](./C++/brace-expansion-ii.cpp) [Python](./Python/brace-expansion-ii.py)  | _O(p * l * log(p * l))_ | _O(p * l)_ | Hard         |||
1219 | [Path with Maximum Gold](https://leetcode.com/problems/path-with-maximum-gold/) | [C++](./C++/path-with-maximum-gold.cpp) [Python](./Python/path-with-maximum-gold.py)  | _O(m^2 * n^2)_ | _O(m * n)_ | Medium         |||
1240 | [Tiling a Rectangle with the Fewest Squares](https://leetcode.com/problems/tiling-a-rectangle-with-the-fewest-squares/) | [C++](./C++/tiling-a-rectangle-with-the-fewest-squares.cpp) [Python](./Python/tiling-a-rectangle-with-the-fewest-squares.py)  | _O(n^2 * m^2 * m^(n * m))_ | _O(n * m)_ | Hard         |||
1255 | [Maximum Score Words Formed by Letters](https://leetcode.com/problems/maximum-score-words-formed-by-letters/) | [C++](./C++/maximum-score-words-formed-by-letters.cpp) [Python](./Python/maximum-score-words-formed-by-letters.py)  | _O(n * 2^n)_ | _O(n)_ | Hard         |||
1258 | [Synonymous Sentences](https://leetcode.com/problems/synonymous-sentences/) | [C++](./C++/synonymous-sentences.cpp) [Python](./Python/synonymous-sentences.py)  | _O(p * l * log(p * l))_ | _O(p * l)_ | Medium         || Union Find |
1307 | [Verbal Arithmetic Puzzle](https://leetcode.com/problems/verbal-arithmetic-puzzle/) | [C++](./C++/verbal-arithmetic-puzzle.cpp) [Python](./Python/verbal-arithmetic-puzzle.py)  | _O(10! * n * l)_ | _O(n * l)_ | Hard         |||
1379 | [Find a Corresponding Node of a Binary Tree in a Clone of That Tree](https://leetcode.com/problems/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree/) | [C++](./C++/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree.cpp) [Python](./Python/find-a-corresponding-node-of-a-binary-tree-in-a-clone-of-that-tree.py) | _O(n)_ | _O(h)_      | Medium         || Stack |
1593 | [Split a String Into the Max Number of Unique Substrings](https://leetcode.com/problems/split-a-string-into-the-max-number-of-unique-substrings/) | [C++](./C++/split-a-string-into-the-max-number-of-unique-substrings.cpp) [Python](./Python/split-a-string-into-the-max-number-of-unique-substrings.py) | _O(n * 2^(n - 1))_ | _O(n)_      | Medium         |||
1659 | [Maximize Grid Happiness](https://leetcode.com/problems/maximize-grid-happiness/) | [C++](./C++/maximize-grid-happiness.cpp) [Python](./Python/maximize-grid-happiness.py) | _O(C(m * n, i) * C(m * n - i, e))_ | _O(min(m * n, i + e))_      | Hard         || Pruning |
1718 | [Construct the Lexicographically Largest Valid Sequence](https://leetcode.com/problems/construct-the-lexicographically-largest-valid-sequence/) | [C++](./C++/construct-the-lexicographically-largest-valid-sequence.cpp) [Python](./Python/construct-the-lexicographically-largest-valid-sequence.py) | _O(n!)_ | _O(b)_      | Medium         || Backtracking |
1723 | [Find Minimum Time to Finish All Jobs](https://leetcode.com/problems/find-minimum-time-to-finish-all-jobs/) | [C++](./C++/find-minimum-time-to-finish-all-jobs.cpp) [Python](./Python/find-minimum-time-to-finish-all-jobs.py) | _O(k^n * logr)_ | _O(n + k)_      | Hard         || Backtracking, Pruning, Binary Search |
1849 | [Splitting a String Into Descending Consecutive Values](https://leetcode.com/problems/splitting-a-string-into-descending-consecutive-values/) | [C++](./C++/splitting-a-string-into-descending-consecutive-values.cpp) [Python](./Python/splitting-a-string-into-descending-consecutive-values.py) | _O(n^2)_ | _O(n)_      | Medium         || |
1999 | [Smallest Greater Multiple Made of Two Digits](https://leetcode.com/problems/smallest-greater-multiple-made-of-two-digits/) | [C++](./C++/smallest-greater-multiple-made-of-two-digits.cpp) [Python](./Python/smallest-greater-multiple-made-of-two-digits.py) | _O(1)_ | _O(1)_      | Medium         |🔒| Backtracking, Bit Manipulation |
2014 | [Longest Subsequence Repeated k Times](https://leetcode.com/problems/longest-subsequence-repeated-k-times/) | [C++](./C++/longest-subsequence-repeated-k-times.cpp) [Python](./Python/longest-subsequence-repeated-k-times.py) | _O(n * (n/k)!)_ | _O(n/k)_      | Hard         | | |
2056 | [Number of Valid Move Combinations On Chessboard](https://leetcode.com/problems/number-of-valid-move-combinations-on-chessboard/) | [C++](./C++/number-of-valid-move-combinations-on-chessboard.cpp) [Python](./Python/number-of-valid-move-combinations-on-chessboard.py) | _O(1)_ | _O(1)_      | Hard         | | |
2094 | [Finding 3-Digit Even Numbers](https://leetcode.com/problems/finding-3-digit-even-numbers/) | [C++](./C++/finding-3-digit-even-numbers.cpp) [Python](./Python/finding-3-digit-even-numbers.py) | _O(n)_ | _O(1)_      | Easy         | | |

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<br/>

## Dynamic Programming
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1027 | [Longest Arithmetic Sequence](https://leetcode.com/problems/longest-arithmetic-sequence/) | [C++](./C++/longest-arithmetic-sequence.cpp) [Python](./Python/longest-arithmetic-sequence.py) |  _O(n^2)_ | _O(n^2)_   | Medium         |||
1035 | [Uncrossed Lines](https://leetcode.com/problems/uncrossed-lines/) | [C++](./C++/uncrossed-lines.cpp) [Python](./Python/uncrossed-lines.py) |  _O(m * n)_ | _O(min(m, n))_   | Medium         |||
1039 | [Minimum Score Triangulation of Polygon](https://leetcode.com/problems/minimum-score-triangulation-of-polygon/) | [C++](./C++/minimum-score-triangulation-of-polygon.cpp) [Python](./Python/minimum-score-triangulation-of-polygon.py) |  _O(n^3)_ | _O(n^2)_   | Medium         |||
1043 | [Partition Array for Maximum Sum](https://leetcode.com/problems/partition-array-for-maximum-sum/) | [C++](./C++/partition-array-for-maximum-sum.cpp) [Python](./Python/partition-array-for-maximum-sum.py) |  _O(n * k)_ | _O(k)_   | Medium         |||
1048 | [Longest String Chain](https://leetcode.com/problems/longest-string-chain/) | [C++](./C++/longest-string-chain.cpp) [Python](./Python/longest-string-chain.py) |  _O(n * l^2)_ | _O(n * l)_   | Medium         |||
1049 | [Last Stone Weight II](https://leetcode.com/problems/last-stone-weight-ii/) | [C++](./C++/last-stone-weight-ii.cpp) [Python](./Python/last-stone-weight-ii.py) |  _O(2^n)_ | _O(2^n)_   | Medium         |||
1066 | [Campus Bikes II](https://leetcode.com/problems/campus-bikes-ii/) | [C++](./C++/campus-bikes-ii.cpp) [Python](./Python/campus-bikes-ii.py) |  _O(w * b * 2^b)_ | _O(w * b * 2^b)_   | Medium         |🔒||
1092 | [Shortest Common Supersequence](https://leetcode.com/problems/shortest-common-supersequence/) | [C++](./C++/shortest-common-supersequence.cpp) [Python](./Python/shortest-common-supersequence.py) |  _O(m * n)_ | _O(m * n)_   | Hard         |||
1105 | [Filling Bookcase Shelves](https://leetcode.com/problems/filling-bookcase-shelves/) | [C++](./C++/filling-bookcase-shelves.cpp) [Python](./Python/filling-bookcase-shelves.py) |  _O(n^2)_ | _O(n)_   | Medium         |||
1125 | [Smallest Sufficient Team](https://leetcode.com/problems/smallest-sufficient-team/) | [C++](./C++/smallest-sufficient-team.cpp) [Python](./Python/smallest-sufficient-team.py) |  _O(m * 2^n)_ | _O(2^n)_   | Hard         |||
1137 | [N-th Tribonacci Number](https://leetcode.com/problems/n-th-tribonacci-number/)| [C++](./C++/n-th-tribonacci-number.cpp) [Python](./Python/n-th-tribonacci-number.py) | _O(logn)_    | _O(1)_          | Easy           | variant of [Fibonacci Number](https://leetcode.com/problems/fibonacci-number/) | Matrix Exponentiation
1139 | [Largest 1-Bordered Square](https://leetcode.com/problems/largest-1-bordered-square/)| [C++](./C++/largest-1-bordered-square.cpp) [Python](./Python/largest-1-bordered-square.py) | _O(n^3)_    | _O(n^2)_          | Medium           | |
1140 | [Stone Game II](https://leetcode.com/problems/stone-game-ii/) | [C++](./C++/stone-game-ii.cpp) [Python](./Python/stone-game-ii.py) | _O(n*(logn)^2)_ | _O(nlogn)_ | Medium || |
1143 | [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/) | [C++](./C++/longest-common-subsequence.cpp) [Python](./Python/longest-common-subsequence.py) | _O(m * n)_ | _O(min(m, n))_ | Medium || |
1155 | [Number of Dice Rolls With Target Sum](https://leetcode.com/problems/number-of-dice-rolls-with-target-sum/) | [C++](./C++/number-of-dice-rolls-with-target-sum.cpp) [Python](./Python/number-of-dice-rolls-with-target-sum.py) | _O(d * f * t)_ | _O(t)_ | Medium || |
1182 | [Shortest Distance to Target Color](https://leetcode.com/problems/shortest-distance-to-target-color/) | [C++](./C++/shortest-distance-to-target-color.cpp) [Python](./Python/shortest-distance-to-target-color.py) | _O(n)_ | _O(n)_ | Medium |🔒| |
1186 | [Maximum Subarray Sum with One Deletion](https://leetcode.com/problems/maximum-subarray-sum-with-one-deletion/)|[C++](./C++/maximum-subarray-sum-with-one-deletion.cpp) [Python](./Python/maximum-subarray-sum-with-one-deletion.py)| _O(n)_     | _O(1)_         | Medium         ||
1187 | [Make Array Strictly Increasing](https://leetcode.com/problems/make-array-strictly-increasing/) | [C++](./C++/make-array-strictly-increasing.cpp) [Python](./Python/make-array-strictly-increasing.py) | _O(n^2 * logn)_ | _O(n)_ | Hard || |
1191 | [K-Concatenation Maximum Sum](https://leetcode.com/problems/k-concatenation-maximum-sum/) | [C++](./C++/k-concatenation-maximum-sum.cpp) [Python](./Python/k-concatenation-maximum-sum.py) | _O(n)_ | _O(1)_ | Medium || |
1216 | [Valid Palindrome III](https://leetcode.com/problems/valid-palindrome-iii/) | [C++](./C++/valid-palindrome-iii.cpp) [Python](./Python/valid-palindrome-iii.py) | _O(n^2)_ | _O(n)_ | Hard | 🔒, variant of [Longest Palindromic Subsequence](https://leetcode.com/problems/longest-palindromic-subsequence/) ||
1218 | [Longest Arithmetic Subsequence of Given Difference](https://leetcode.com/problems/longest-arithmetic-subsequence-of-given-difference/) | [C++](./C++/longest-arithmetic-subsequence-of-given-difference.cpp) [Python](./Python/longest-arithmetic-subsequence-of-given-difference.py) | _O(n)_ | _O(n)_ | Medium | ||
1220 | [Count Vowels Permutation](https://leetcode.com/problems/count-vowels-permutation/) | [C++](./C++/count-vowels-permutation.cpp) [Python](./Python/count-vowels-permutation.py) | _O(logn)_ | _O(1)_ | Hard || Matrix Exponentiation |
1223 | [Dice Roll Simulation](https://leetcode.com/problems/dice-roll-simulation/) | [C++](./C++/dice-roll-simulation.cpp) [Python](./Python/dice-roll-simulation.py) | _O(m * n)_ | _O(m)_ | Medium | ||
1230 | [Toss Strange Coins](https://leetcode.com/problems/toss-strange-coins/) | [C++](./C++/toss-strange-coins.cpp) [Python](./Python/toss-strange-coins.py) | _O(n^2)_ | _O(n)_ | Medium | ||
1235 | [Maximum Profit in Job Scheduling](https://leetcode.com/problems/maximum-profit-in-job-scheduling/) | [C++](./C++/maximum-profit-in-job-scheduling.cpp) [Python](./Python/maximum-profit-in-job-scheduling.py) | _O(nlogn)_ | _O(n)_ | Hard | | DP, Heap |
1239 | [Maximum Length of a Concatenated String with Unique Characters](https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters/) | [C++](./C++/maximum-length-of-a-concatenated-string-with-unique-characters.cpp) [Python](./Python/maximum-length-of-a-concatenated-string-with-unique-characters.py) | _O(n)_ ~ _O(2^n)_ | _O(1)_ ~ _O(2^n)_ | Medium | | DP, Bit Manipulation |
1246 | [Palindrome Removal](https://leetcode.com/problems/palindrome-removal/) | [C++](./C++/palindrome-removal.cpp) [Python](./Python/palindrome-removal.py) | _O(n^3)_ | _O(n^2)_ | Hard | | |
1262 | [Greatest Sum Divisible by Three](https://leetcode.com/problems/greatest-sum-divisible-by-three/) | [C++](./C++/greatest-sum-divisible-by-three.cpp) [Python](./Python/greatest-sum-divisible-by-three.py) | _O(n)_ | _O(1)_ | Medium | | |
1269 | [Number of Ways to Stay in the Same Place After Some Steps](https://leetcode.com/problems/number-of-ways-to-stay-in-the-same-place-after-some-steps/) | [C++](./C++/number-of-ways-to-stay-in-the-same-place-after-some-steps.cpp) [Python](./Python/number-of-ways-to-stay-in-the-same-place-after-some-steps.py) | _O(n^2)_ | _O(n)_ | Hard | | |
1277 | [Count Square Submatrices with All Ones](https://leetcode.com/problems/count-square-submatrices-with-all-ones/) | [C++](./C++/count-square-submatrices-with-all-ones.cpp) [Python](./Python/count-square-submatrices-with-all-ones.py) | _O(m * n)_ | _O(1)_ | Medium | | |
1278 | [Palindrome Partitioning III](https://leetcode.com/problems/palindrome-partitioning-iii/) | [C++](./C++/palindrome-partitioning-iii.cpp) [Python](./Python/palindrome-partitioning-iii.py) | _O(k * n^2)_ | _O(n^2)_ | Hard | | |
1289 | [Minimum Falling Path Sum II](https://leetcode.com/problems/minimum-falling-path-sum-ii/) | [C++](./C++/minimum-falling-path-sum-ii.cpp) [Python](./Python/minimum-falling-path-sum-ii.py) | _O(m * n)_ | _O(1)_ | Hard | | |
1292 | [Maximum Side Length of a Square with Sum Less than or Equal to Threshold](https://leetcode.com/problems/maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold/) | [C++](./C++/maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold.cpp) [Python](./Python/maximum-side-length-of-a-square-with-sum-less-than-or-equal-to-threshold.py) | _O(m * n * log(min(m, n)))_ | _O(m * n)_ | Medium | | Binary Search |
1301 | [Number of Paths with Max Score](https://leetcode.com/problems/number-of-paths-with-max-score/) | [C++](./C++/number-of-paths-with-max-score.cpp) [Python](./Python/number-of-paths-with-max-score.py) | _O(n^2)_ | _O(n)_ | Hard | | |
1312 | [Minimum Insertion Steps to Make a String Palindrome](https://leetcode.com/problems/minimum-insertion-steps-to-make-a-string-palindrome/) | [C++](./C++/minimum-insertion-steps-to-make-a-string-palindrome.cpp) [Python](./Python/minimum-insertion-steps-to-make-a-string-palindrome.py) | _O(n^2)_ | _O(n)_ | Hard | variant of [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/) | |
1314 | [Matrix Block Sum](https://leetcode.com/problems/matrix-block-sum/) | [C++](./C++/matrix-block-sum.cpp) [Python](./Python/matrix-block-sum.py) | _O(m * n)_ | _O(m * n)_ | Medium | variant of [Range Sum Query 2D - Immutable](https://leetcode.com/problems/range-sum-query-2d-immutable/) | |
1320 | [Minimum Distance to Type a Word Using Two Fingers](https://leetcode.com/problems/minimum-distance-to-type-a-word-using-two-fingers/) | [C++](./C++/minimum-distance-to-type-a-word-using-two-fingers.cpp) [Python](./Python/minimum-distance-to-type-a-word-using-two-fingers.py) | _O(n)_ | _O(1)_ | Hard | | |
1335 | [Minimum Difficulty of a Job Schedule](https://leetcode.com/problems/minimum-difficulty-of-a-job-schedule/) | [C++](./C++/minimum-difficulty-of-a-job-schedule.cpp) [Python](./Python/minimum-difficulty-of-a-job-schedule.py) | _O(d * n^2)_ | _O(d * n)_ | Hard | | |
1340 | [Jump Game V](https://leetcode.com/problems/jump-game-v/) | [C++](./C++/jump-game-v.cpp) [Python](./Python/jump-game-v.py) | _O(n)_ | _O(n)_ | Hard | | Sliding Window, Mono Stack, Segment Tree |
1387 | [Sort Integers by The Power Value](https://leetcode.com/problems/sort-integers-by-the-power-value/) | [C++](./C++/sort-integers-by-the-power-value.cpp) [Python](./Python/sort-integers-by-the-power-value.py) | _O(n)_ on average| _O(n)_ | Medium | | Quick Select |
1388 | [Pizza With 3n Slices](https://leetcode.com/problems/pizza-with-3n-slices/)| [C++](./C++/pizza-with-3n-slices.cpp) [Python](./Python/pizza-with-3n-slices.py) | _O(n^2)_          | _O(n)_          | Hard           | variant of [House Robber II](https://leetcode.com/problems/house-robber-ii/) |
1395 | [Count Number of Teams](https://leetcode.com/problems/count-number-of-teams/)| [C++](./C++/count-number-of-teams.cpp) [Python](./Python/count-number-of-teams.py) | _O(n^2)_          | _O(1)_          | Medium           ||
1397 | [Find All Good Strings](https://leetcode.com/problems/find-all-good-strings/)| [C++](./C++/find-all-good-strings.cpp) [Python](./Python/find-all-good-strings.py) | _O(m * n)_          | _O(m)_          | Hard           || `KMP Algorithm`
1406 | [Stone Game III](https://leetcode.com/problems/stone-game-iii/)| [C++](./C++/stone-game-iii.cpp) [Python](./Python/stone-game-iii.py) | _O(n)_          | _O(1)_          | Hard           ||
1411 | [Number of Ways to Paint N × 3 Grid](https://leetcode.com/problems/number-of-ways-to-paint-n-3-grid/)| [C++](./C++/number-of-ways-to-paint-n-3-grid.cpp) [Python](./Python/number-of-ways-to-paint-n-3-grid.py) | _O(logn)_    | _O(1)_          | Hard           || Matrix Exponentiation
1416 | [Restore The Array](https://leetcode.com/problems/restore-the-array/)| [C++](./C++/restore-the-array.cpp) [Python](./Python/restore-the-array.py) | _O(nlogk)_    | _O(logk)_          | Hard           ||
1420 | [Build Array Where You Can Find The Maximum Exactly K Comparisons](https://leetcode.com/problems/build-array-where-you-can-find-the-maximum-exactly-k-comparisons/)| [C++](./C++/build-array-where-you-can-find-the-maximum-exactly-k-comparisons.cpp) [Python](./Python/build-array-where-you-can-find-the-maximum-exactly-k-comparisons.py) | _O(n * m * k)_    | _O(m * k)_          | Hard           ||
1434 | [Number of Ways to Wear Different Hats to Each Other](https://leetcode.com/problems/number-of-ways-to-wear-different-hats-to-each-other/)| [C++](./C++/number-of-ways-to-wear-different-hats-to-each-other.cpp) [Python](./Python/number-of-ways-to-wear-different-hats-to-each-other.py) | _O(h * 2^n)_    | _O(2^n)_          | Hard           ||
1444 | [Number of Ways of Cutting a Pizza](https://leetcode.com/problems/number-of-ways-of-cutting-a-pizza/)| [C++](./C++/number-of-ways-of-cutting-a-pizza.cpp) [Python](./Python/number-of-ways-of-cutting-a-pizza.py) | _O(m * n * k * (m + n))_    | _O(m * n * k)_          | Hard           ||
1449 | [Form Largest Integer With Digits That Add up to Target](https://leetcode.com/problems/form-largest-integer-with-digits-that-add-up-to-target/)| [C++](./C++/form-largest-integer-with-digits-that-add-up-to-target.cpp) [Python](./Python/form-largest-integer-with-digits-that-add-up-to-target.py) | _O(t)_    | _O(t)_          | Hard           ||
1458 | [Max Dot Product of Two Subsequences](https://leetcode.com/problems/max-dot-product-of-two-subsequences/)| [C++](./C++/max-dot-product-of-two-subsequences.cpp) [Python](./Python/max-dot-product-of-two-subsequences.py) | _O(m * n)_    | _O(min(m, n))_          | Hard           ||
1463 | [Cherry Pickup II](https://leetcode.com/problems/cherry-pickup-ii/)| [C++](./C++/cherry-pickup-ii.cpp) [Python](./Python/cherry-pickup-ii.py) | _O(m * n^2)_    | _O(n^2)_          | Hard           ||
1467 | [Probability of a Two Boxes Having The Same Number of Distinct Balls](https://leetcode.com/problems/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls/)| [C++](./C++/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls.cpp) [Python](./Python/probability-of-a-two-boxes-having-the-same-number-of-distinct-balls.py) | _O(k^3 * n^2)_    | _O(k^2 * n)_          | Hard           || Binomial Coefficients
1473 | [Paint House III](https://leetcode.com/problems/paint-house-iii/)| [C++](./C++/paint-house-iii.cpp) [Python](./Python/paint-house-iii.py) | _O(m * t * n^2)_    | _O(t * n)_          | Hard           ||
1477 | [Find Two Non-overlapping Sub-arrays Each With Target Sum](https://leetcode.com/problems/find-two-non-overlapping-sub-arrays-each-with-target-sum/)| [C++](./C++/find-two-non-overlapping-sub-arrays-each-with-target-sum.cpp) [Python](./Python/find-two-non-overlapping-sub-arrays-each-with-target-sum.py) | _O(n)_    | _O(n)_          | Medium           ||
1478 | [Allocate Mailboxes](https://leetcode.com/problems/allocate-mailboxes/)| [C++](./C++/allocate-mailboxes.cpp) [Python](./Python/allocate-mailboxes.py) | _O(m * n^2)_    | _O(n)_          | Hard           || DP, Math, Median
1494 | [Parallel Courses II](https://leetcode.com/problems/parallel-courses-ii/)| [C++](./C++/parallel-courses-ii.cpp) [Python](./Python/parallel-courses-ii.py) | _O((n * C(c, min(c, k))) * 2^n)_    | _O(2^n)_          | Hard           || Combinations
1504 | [Count Submatrices With All Ones](https://leetcode.com/problems/count-submatrices-with-all-ones/) | [C++](./C++/count-submatrices-with-all-ones.cpp) [Python](./Python/count-submatrices-with-all-ones.py) | _O(m * n)_ | _O(n)_ | Medium | | Mono Stack
1510 | [Stone Game IV](https://leetcode.com/problems/stone-game-iv/)| [C++](./C++/stone-game-iv.cpp) [Python](./Python/stone-game-iv.py) | _O(n * sqrt(n))_    | _O(n)_          | Hard           ||
1524 | [Number of Sub-arrays With Odd Sum](https://leetcode.com/problems/number-of-sub-arrays-with-odd-sum/)| [C++](./C++/number-of-sub-arrays-with-odd-sum.cpp) [Python](./Python/number-of-sub-arrays-with-odd-sum.py) | _O(n)_    | _O(1)_          | Medium           ||
1531 | [String Compression II](https://leetcode.com/problems/string-compression-ii/)| [C++](./C++/string-compression-ii.cpp) [Python](./Python/string-compression-ii.py) | _O(n^2 * k)_    | _O(n * k)_          | Hard           ||
1547 | [Minimum Cost to Cut a Stick](https://leetcode.com/problems/minimum-cost-to-cut-a-stick/)| [C++](./C++/minimum-cost-to-cut-a-stick.cpp) [Python](./Python/minimum-cost-to-cut-a-stick.py) | _O(n^3)_    | _O(n^2)_          | Hard           ||
1548 | [The Most Similar Path in a Graph](https://leetcode.com/problems/the-most-similar-path-in-a-graph/)| [C++](./C++/the-most-similar-path-in-a-graph.cpp) [Python](./Python/the-most-similar-path-in-a-graph.py) | _O(n^ * m)_    | _O(n * m)_          | Hard           | 🔒 |
1553 | [Minimum Number of Days to Eat N Oranges](https://leetcode.com/problems/minimum-number-of-days-to-eat-n-oranges/)| [C++](./C++/minimum-number-of-days-to-eat-n-oranges.cpp) [Python](./Python/minimum-number-of-days-to-eat-n-oranges.py) | _O((logn)^2)_    | _O((logn)^2)_          | Hard           ||
1563 | [Stone Game V](https://leetcode.com/problems/stone-game-v/)| [C++](./C++/stone-game-v.cpp) [Python](./Python/stone-game-v.py) | _O(n^2)_    | _O(n^2)_          | Hard           ||
1569 | [Number of Ways to Reorder Array to Get Same BST](https://leetcode.com/problems/detect-pattern-of-length-m-repeated-k-or-more-times/)| [C++](./C++/detect-pattern-of-length-m-repeated-k-or-more-times.cpp) [Python](./Python/detect-pattern-of-length-m-repeated-k-or-more-times.py) | _O(n^2)_    | _O(n^2)_          | Hard           || DFS
1575 | [Count All Possible Routes](https://leetcode.com/problems/count-all-possible-routes/)| [C++](./C++/count-all-possible-routes.cpp) [Python](./Python/count-all-possible-routes.py) | _O(nlogn + n * f)_    | _O(n * f)_          | Hard           || Math
1594 | [Maximum Non Negative Product in a Matrix](https://leetcode.com/problems/maximum-non-negative-product-in-a-matrix/)| [C++](./C++/maximum-non-negative-product-in-a-matrix.cpp) [Python](./Python/maximum-non-negative-product-in-a-matrix.py) | _O(m * n)_    | _O(n)_          | Medium           || 
1595 | [Minimum Cost to Connect Two Groups of Points](https://leetcode.com/problems/minimum-cost-to-connect-two-groups-of-points/)| [C++](./C++/minimum-cost-to-connect-two-groups-of-points.cpp) [Python](./Python/minimum-cost-to-connect-two-groups-of-points.py) | _O(m * n * 2^n)_    | _O(2^n)_          | Hard           ||
1617 | [Count Subtrees With Max Distance Between Cities](https://leetcode.com/problems/count-subtrees-with-max-distance-between-cities/)| [C++](./C++/count-subtrees-with-max-distance-between-cities.cpp) [Python](./Python/count-subtrees-with-max-distance-between-cities.py) | _O(n^6)_    | _O(n^3)_          | Hard           || Backtracking, Graph
1626 | [Best Team With No Conflicts](https://leetcode.com/problems/best-team-with-no-conflicts/)| [C++](./C++/best-team-with-no-conflicts.cpp) [Python](./Python/best-team-with-no-conflicts.py) | _O(nloga)_    | _O(n)_          | Medium           | variant of [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | Sort, DP, Segment Tree
1639 | [Number of Ways to Form a Target String Given a Dictionary](https://leetcode.com/problems/number-of-ways-to-form-a-target-string-given-a-dictionary/)| [C++](./C++/number-of-ways-to-form-a-target-string-given-a-dictionary.cpp) [Python](./Python/number-of-ways-to-form-a-target-string-given-a-dictionary.py) | _O(l * (w + n))_    | _O(n)_          | Hard           | | 
1655 | [Distribute Repeating Integers](https://leetcode.com/problems/distribute-repeating-integers/)| [C++](./C++/distribute-repeating-integers.cpp) [Python](./Python/distribute-repeating-integers.py) | _O(n + m * 3^m)_    | _O(n + 2^m)_          | Hard           | | Submask Enumeration
1664 | [Ways to Make a Fair Array](https://leetcode.com/problems/ways-to-make-a-fair-array/)| [C++](./C++/ways-to-make-a-fair-array.cpp) [Python](./Python/ways-to-make-a-fair-array.py) | _O(n)_    | _O(1)_          | Medium           | | Prefix Sum
1681 | [Minimum Incompatibility](https://leetcode.com/problems/minimum-incompatibility/)| [C++](./C++/minimum-incompatibility.cpp) [Python](./Python/minimum-incompatibility.py) | _O(max(n * 2^n, 3^n))_    | _O(2^n)_          | Hard           | | Combinations, Backtracking, Submask Enumeration
1682 | [Longest Palindromic Subsequence II](https://leetcode.com/problems/longest-palindromic-subsequence-ii/) | [C++](./C++/longest-palindromic-subsequence-ii.cpp) [Python](./Python/longest-palindromic-subsequence-ii.py) | _O(n^2)_ | _O(n)_ | Medium |🔒||
1690 | [Stone Game VII](https://leetcode.com/problems/stone-game-vii/) | [C++](./C++/stone-game-vii.cpp) [Python](./Python/stone-game-vii.py) | _O(n^2)_ | _O(n)_ | Medium |||
1691 | [Maximum Height by Stacking Cuboids](https://leetcode.com/problems/maximum-height-by-stacking-cuboids/) | [C++](./C++/maximum-height-by-stacking-cuboids.cpp) [Python](./Python/maximum-height-by-stacking-cuboids.py) | _O(n^2)_ | _O(n)_ | Hard |||
1692 | [Count Ways to Distribute Candies](https://leetcode.com/problems/count-ways-to-distribute-candies/) | [C++](./C++/count-ways-to-distribute-candies.cpp) [Python](./Python/count-ways-to-distribute-candies.py) | _O(n * k)_ | _O(k)_ | Hard |🔒||
1745 | [Palindrome Partitioning IV](https://leetcode.com/problems/palindrome-partitioning-iv/) | [C++](./C++/palindrome-partitioning-iv.cpp) [Python](./Python/palindrome-partitioning-iv.py) | _O(n^2)_ | _O(n)_ | Hard | | DP, `Manacher's Algorithm` |
1746 | [Maximum Subarray Sum After One Operation](https://leetcode.com/problems/maximum-subarray-sum-after-one-operation/)|[C++](./C++/maximum-subarray-sum-after-one-operation.cpp) [Python](./Python/maximum-subarray-sum-after-one-operation.py)| _O(n)_     | _O(1)_         | Medium         | variant of [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/), 🔒 |
1751 | [Maximum Number of Events That Can Be Attended II](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended-ii/)|[C++](./C++/maximum-number-of-events-that-can-be-attended-ii.cpp) [Python](./Python/maximum-number-of-events-that-can-be-attended-ii.py)| _O(nlogn + n * k)_     | _O(n * k)_         | Hard         | | Binary Search
1770 | [Maximum Score from Performing Multiplication Operations](https://leetcode.com/problems/maximum-score-from-performing-multiplication-operations/)|[C++](./C++/maximum-score-from-performing-multiplication-operations.cpp) [Python](./Python/maximum-score-from-performing-multiplication-operations.py)| _O(m^2)_     | _O(m)_         | Medium         | |
1771 | [Maximize Palindrome Length From Subsequences](https://leetcode.com/problems/maximize-palindrome-length-from-subsequences/)|[C++](./C++/maximize-palindrome-length-from-subsequences.cpp) [Python](./Python/maximize-palindrome-length-from-subsequences.py)| _O((m + n)^2)_     | _O((m + n)^2)_         | Hard         | |
1774 | [Closest Dessert Cost](https://leetcode.com/problems/closest-dessert-cost/)|[C++](./C++/closest-dessert-cost.cpp) [Python](./Python/closest-dessert-cost.py)| _O(m * t)_     | _O(t)_         | Medium         | |
1787 | [Make the XOR of All Segments Equal to Zero](https://leetcode.com/problems/make-the-xor-of-all-segments-equal-to-zero/)|[C++](./C++/make-the-xor-of-all-segments-equal-to-zero.cpp) [Python](./Python/make-the-xor-of-all-segments-equal-to-zero.py)| _O(n + k * m)_     | _O(min(k * m, n))_         | Hard         | |
1799 | [Maximize Score After N Operations](https://leetcode.com/problems/maximize-score-after-n-operations/)|[C++](./C++/maximize-score-after-n-operations.cpp) [Python](./Python/maximize-score-after-n-operations.py)| _O(n^2 * 2^n)_     | _O(2^n)_         | Hard         | |
1803 | [Count Pairs With XOR in a Range](https://leetcode.com/problems/count-pairs-with-xor-in-a-range/)|[C++](./C++/count-pairs-with-xor-in-a-range.cpp) [Python](./Python/count-pairs-with-xor-in-a-range.py)| _O(n)_     | _O(n)_         | Hard         | | DP, Trie
1857 | [Largest Color Value in a Directed Graph](https://leetcode.com/problems/largest-color-value-in-a-directed-graph/)|[C++](./C++/largest-color-value-in-a-directed-graph.cpp) [Python](./Python/largest-color-value-in-a-directed-graph.py)| _O(n + m)_     | _O(n + m)_         | Hard         | | DP, Topological Sort
1866 | [Number of Ways to Rearrange Sticks With K Sticks Visible](https://leetcode.com/problems/number-of-ways-to-rearrange-sticks-with-k-sticks-visible/)|[C++](./C++/number-of-ways-to-rearrange-sticks-with-k-sticks-visible.cpp) [Python](./Python/number-of-ways-to-rearrange-sticks-with-k-sticks-visible.py)| _O(n * k)_     | _O(k)_         | Hard         | | 
1871 | [Jump Game VII](https://leetcode.com/problems/jump-game-vii/)|[C++](./C++/jump-game-vii.cpp) [Python](./Python/jump-game-vii.py)| _O(n)_     | _O(n)_         | Medium         | | Line Sweep, DP, BFS
1872 | [Stone Game VIII](https://leetcode.com/problems/stone-game-viii/)|[C++](./C++/stone-game-viii.cpp) [Python](./Python/stone-game-viii.py)| _O(n)_     | _O(1)_         | Hard         | |
1883 | [Minimum Skips to Arrive at Meeting On Time](https://leetcode.com/problems/minimum-skips-to-arrive-at-meeting-on-time/)|[C++](./C++/minimum-skips-to-arrive-at-meeting-on-time.cpp) [Python](./Python/minimum-skips-to-arrive-at-meeting-on-time.py)| _O(n^2)_     | _O(n)_         | Hard         | |
1896 | [Minimum Cost to Change the Final Value of Expression](https://leetcode.com/problems/minimum-cost-to-change-the-final-value-of-expression/)|[C++](./C++/minimum-cost-to-change-the-final-value-of-expression.cpp) [Python](./Python/minimum-cost-to-change-the-final-value-of-expression.py)| _O(n)_     | _O(n)_         | Hard         | | Stack, DP |
1900 | [The Earliest and Latest Rounds Where Players Compete](https://leetcode.com/problems/the-earliest-and-latest-rounds-where-players-compete/)|[C++](./C++/the-earliest-and-latest-rounds-where-players-compete.cpp) [Python](./Python/the-earliest-and-latest-rounds-where-players-compete.py)| _O(n^4)_     | _O(n^2)_         | Hard         | | |
1908 | [Game of Nim](https://leetcode.com/problems/game-of-nim/)|[C++](./C++/game-of-nim.cpp) [Python](./Python/game-of-nim.py)| _O(n)_     | _O(1)_         | Medium         | 🔒 | |
1931 | [Painting a Grid With Three Different Colors](https://leetcode.com/problems/painting-a-grid-with-three-different-colors/)|[C++](./C++/painting-a-grid-with-three-different-colors.cpp) [Python](./Python/painting-a-grid-with-three-different-colors.py)| _O(2^(3 * m) * logn)_     | _O(2^(2 * m))_         | Hard         | variant of [Number of Ways to Paint N × 3 Grid](https://leetcode.com/problems/number-of-ways-to-paint-n-3-grid/) | DP, Backtracking, Matrix Exponentiation, State Compression |
1937 | [Maximum Number of Points with Cost](https://leetcode.com/problems/maximum-number-of-points-with-cost/)|[C++](./C++/maximum-number-of-points-with-cost.cpp) [Python](./Python/maximum-number-of-points-with-cost.py)| _O(m * n)_     | _O(n)_         | Medium         | | Prefix Sum |
1955 | [Count Number of Special Subsequences](https://leetcode.com/problems/count-number-of-special-subsequences/)|[C++](./C++/count-number-of-special-subsequences.cpp) [Python](./Python/count-number-of-special-subsequences.py)| _O(n)_     | _O(1)_         | Hard         | | |
1959 | [Minimum Total Space Wasted With K Resizing Operations](https://leetcode.com/problems/minimum-total-space-wasted-with-k-resizing-operations/)|[C++](./C++/minimum-total-space-wasted-with-k-resizing-operations.cpp) [Python](./Python/minimum-total-space-wasted-with-k-resizing-operations.py)| _O(k * n^2)_     | _O(k * n)_         | Medium         | | |
1960 | [Maximum Product of the Length of Two Palindromic Substrings](https://leetcode.com/problems/maximum-product-of-the-length-of-two-palindromic-substrings/)|[C++](./C++/maximum-product-of-the-length-of-two-palindromic-substrings.cpp) [Python](./Python/maximum-product-of-the-length-of-two-palindromic-substrings.py)| _O(n)_     | _O(n)_         | Hard         | | `Manacher's Algorithm`, DP |
1977 | [Number of Ways to Separate Numbers](https://leetcode.com/problems/number-of-ways-to-separate-numbers/)|[C++](./C++/number-of-ways-to-separate-numbers.cpp) [Python](./Python/number-of-ways-to-separate-numbers.py)| _O(n^2)_     | _O(n^2)_         | Hard         | | DP |
1981 | [Minimize the Difference Between Target and Chosen Elements](https://leetcode.com/problems/minimize-the-difference-between-target-and-chosen-elements/)|[C++](./C++/minimize-the-difference-between-target-and-chosen-elements.cpp) [Python](./Python/minimize-the-difference-between-target-and-chosen-elements.py)| _O(t * m * n)_     | _O(t)_         | Medium         | | DP, Pruning |
1986 | [Minimum Number of Work Sessions to Finish the Tasks](https://leetcode.com/problems/minimum-number-of-work-sessions-to-finish-the-tasks/)|[C++](./C++/minimum-number-of-work-sessions-to-finish-the-tasks.cpp) [Python](./Python/minimum-number-of-work-sessions-to-finish-the-tasks.py)| _O(n * 2^n)_     | _O(2^n)_         | Medium         | | DP |
1987 | [Number of Unique Good Subsequences](https://leetcode.com/problems/number-of-unique-good-subsequences/)|[C++](./C++/number-of-unique-good-subsequences.cpp) [Python](./Python/number-of-unique-good-subsequences.py)| _O(n)_     | _O(1)_         | Hard         | variant of [Distinct Subsequences II](https://leetcode.com/problems/distinct-subsequences-ii/) | DP |
1994 | [The Number of Good Subsets](https://leetcode.com/problems/the-number-of-good-subsets/)|[C++](./C++/the-number-of-good-subsets.cpp) [Python](./Python/the-number-of-good-subsets.py)| _O(n * 2^p)_     | _O(2^p)_         | Hard         |  | DP, `Sieve of Eratosthenes` |
1997 | [First Day Where You Have Been in All the Rooms](https://leetcode.com/problems/first-day-where-you-have-been-in-all-the-rooms/)|[C++](./C++/first-day-where-you-have-been-in-all-the-rooms.cpp) [Python](./Python/first-day-where-you-have-been-in-all-the-rooms.py)| _O(n)_     | _O(n)_         | Medium         |  | DP |
2002 | [Maximum Product of the Length of Two Palindromic Subsequences](https://leetcode.com/problems/maximum-product-of-the-length-of-two-palindromic-subsequences/)| [C++](./C++/maximum-product-of-the-length-of-two-palindromic-subsequences.cpp) [Python](./Python/maximum-product-of-the-length-of-two-palindromic-subsequences.py) | _O(3^n)_    | _O(2^n)_          | Medium           | | DP, Submask Enumeration
2008 | [Maximum Earnings From Taxi](https://leetcode.com/problems/maximum-earnings-from-taxi/)| [C++](./C++/maximum-earnings-from-taxi.cpp) [Python](./Python/maximum-earnings-from-taxi.py) | _O(n + mlogm)_    | _O(n)_          | Medium           | | DP
2019 | [The Score of Students Solving Math Expression](https://leetcode.com/problems/the-score-of-students-solving-math-expression/) | [C++](./C++/the-score-of-students-solving-math-expression.cpp) [Python](./Python/the-score-of-students-solving-math-expression.py) | _O(n^3 * a^2)_ | _O(n^2)_ | Hard | variant of [Burst Balloons](https://leetcode.com/problems/burst-balloons/) |
2031 | [Count Subarrays With More Ones Than Zeros](https://leetcode.com/problems/count-subarrays-with-more-ones-than-zeros/) | [C++](./C++/count-subarrays-with-more-ones-than-zeros.cpp) [Python](./Python/count-subarrays-with-more-ones-than-zeros.py) | _O(n)_ | _O(n)_ | Medium | 🔒 | Prefix Sum, DP
2044 | [Count Number of Maximum Bitwise-OR Subsets](https://leetcode.com/problems/count-number-of-maximum-bitwise-or-subsets/) | [C++](./C++/count-number-of-maximum-bitwise-or-subsets.cpp) [Python](./Python/count-number-of-maximum-bitwise-or-subsets.py) | _O(min(2^n, m * n))_ | _O(min(2^n, m))_ | Medium | | DP
2052 | [Minimum Cost to Separate Sentence Into Rows](https://leetcode.com/problems/minimum-cost-to-separate-sentence-into-rows/) | [C++](./C++/minimum-cost-to-separate-sentence-into-rows.cpp) [Python](./Python/minimum-cost-to-separate-sentence-into-rows.py) | _O(s + n * k)_ | _O(k)_ | Medium | 🔒 | DP
2060 | [Check if an Original String Exists Given Two Encoded Strings](https://leetcode.com/problems/check-if-an-original-string-exists-given-two-encoded-strings/) | [C++](./C++/check-if-an-original-string-exists-given-two-encoded-strings.cpp) [Python](./Python/check-if-an-original-string-exists-given-two-encoded-strings.py) | _O(m * n * k)_ | _O(min(m, n) * k)_ | Hard | | DP, Memoization
2088 | [Count Fertile Pyramids in a Land](https://leetcode.com/problems/count-fertile-pyramids-in-a-land/) | [C++](./C++/count-fertile-pyramids-in-a-land.cpp) [Python](./Python/count-fertile-pyramids-in-a-land.py) | _O(m * n)_ | _O(n)_ | Hard | | DP
2140 | [Solving Questions With Brainpower](https://leetcode.com/problems/solving-questions-with-brainpower/) | [C++](./C++/solving-questions-with-brainpower.cpp) [Python](./Python/solving-questions-with-brainpower.py) | _O(n)_ | _O(n)_ | Medium | | DP
2143 | [Choose Numbers From Two Arrays in Range](https://leetcode.com/problems/choose-numbers-from-two-arrays-in-range/) | [C++](./C++/choose-numbers-from-two-arrays-in-range.cpp) [Python](./Python/choose-numbers-from-two-arrays-in-range.py) | _O(n^2 * v)_ | _O(n * v)_ | Hard | 🔒 | DP

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Greedy
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1005 | [Maximize Sum Of Array After K Negations](https://leetcode.com/problems/maximize-sum-of-array-after-k-negations/) | [C++](./C++/maximize-sum-of-array-after-k-negations.cpp) [Python](./Python/maximize-sum-of-array-after-k-negations.py) | _O(n)_ on average | _O(1)_ | Easy || Quick Select
1024 | [Video Stitching](https://leetcode.com/problems/video-stitching/) | [C++](./C++/video-stitching.cpp) [Python](./Python/video-stitching.py) | _O(nlogn)_ | _O(1)_ | Medium | variant of [Jump Game II](https://leetcode.com/problems/jump-game-ii/) |
1029 | [Two City Scheduling](https://leetcode.com/problems/two-city-scheduling/) | [C++](./C++/two-city-scheduling.cpp) [Python](./Python/two-city-scheduling.py) | _O(n)_ on average | _O(1)_ | Easy | | Quick Select
1053 | [Previous Permutation With One Swap](https://leetcode.com/problems/previous-permutation-with-one-swap/) | [C++](./C++/previous-permutation-with-one-swap.cpp) [Python](./Python/previous-permutation-with-one-swap.py) | _O(n)_ | _O(1)_ | Medium | | 
1055 | [Shortest Way to Form String](https://leetcode.com/problems/shortest-way-to-form-string/) | [C++](./C++/shortest-way-to-form-string.cpp) [Python](./Python/shortest-way-to-form-string.py) | _O(m + n)_ | _O(m)_ | Medium | 🔒, variant of [Minimum Window Subsequence](https://leetcode.com/problems/minimum-window-subsequence/) | 
1058 | [Minimize Rounding Error to Meet Target](https://leetcode.com/problems/minimize-rounding-error-to-meet-target/) | [C++](./C++/minimize-rounding-error-to-meet-target.cpp) [Python](./Python/minimize-rounding-error-to-meet-target.py) | _O(n)_ on average | _O(n)_ | Medium | 🔒 | Quick Select
1081 | [Smallest Subsequence of Distinct Characters](https://leetcode.com/problems/smallest-subsequence-of-distinct-characters/) | [C++](./C++/smallest-subsequence-of-distinct-characters.cpp) [Python](./Python/smallest-subsequence-of-distinct-characters.py) | _O(n)_| _O(1)_| Medium | same as [Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters/) | Mono Stack |
1090 | [Largest Values From Labels](https://leetcode.com/problems/largest-values-from-labels/) | [C++](./C++/largest-values-from-labels.cpp) [Python](./Python/largest-values-from-labels.py) | _O(nlogn)_ | _O(n)_ | Medium ||
1111 | [Maximum Nesting Depth of Two Valid Parentheses Strings](https://leetcode.com/problems/maximum-nesting-depth-of-two-valid-parentheses-strings/) | [C++](./C++/maximum-nesting-depth-of-two-valid-parentheses-strings.cpp) [Python](./Python/maximum-nesting-depth-of-two-valid-parentheses-strings.py) | _O(n)_ | _O(1)_ | Medium ||
1163 | [Last Substring in Lexicographical Order](https://leetcode.com/problems/last-substring-in-lexicographical-order/)| [C++](./C++/last-substring-in-lexicographical-order.cpp) [Python](./Python/last-substring-in-lexicographical-order.py)| _O(n)_ | _O(1)_ | Hard | | |
1167 | [Minimum Cost to Connect Sticks](https://leetcode.com/problems/minimum-cost-to-connect-sticks/) | [C++](./C++/minimum-cost-to-connect-sticks.cpp) [Python](./Python/minimum-cost-to-connect-sticks.py) |  _O(nlogn)_ | _O(n)_   | Medium |🔒|| Heap
1183 | [Maximum Number of Ones](https://leetcode.com/problems/maximum-number-of-ones/) | [C++](./C++/maximum-number-of-ones.cpp) [Python](./Python/maximum-number-of-ones.py) |  _O(1)_ | _O(1)_   | Hard |🔒||
1196 | [How Many Apples Can You Put into the Basket](https://leetcode.com/problems/how-many-apples-can-you-put-into-the-basket/) | [C++](./C++/how-many-apples-can-you-put-into-the-basket.cpp) [Python](./Python/how-many-apples-can-you-put-into-the-basket.py) | _O(nlogn)_ | _O(n)_ | Easy |🔒|
1199 | [Minimum Time to Build Blocks](https://leetcode.com/problems/minimum-time-to-build-blocks/) | [C++](./C++/minimum-time-to-build-blocks.cpp) [Python](./Python/minimum-time-to-build-blocks.py) | _O(nlogn)_ | _O(n)_ | Hard |🔒|
1221 | [Split a String in Balanced Strings](https://leetcode.com/problems/split-a-string-in-balanced-strings/) | [C++](./C++/split-a-string-in-balanced-strings.cpp) [Python](./Python/split-a-string-in-balanced-strings.py) | _O(n)_ | _O(1)_ | Easy ||
1247 | [Minimum Swaps to Make Strings Equal](https://leetcode.com/problems/minimum-swaps-to-make-strings-equal/) | [C++](./C++/minimum-swaps-to-make-strings-equal.cpp) [Python](./Python/minimum-swaps-to-make-strings-equal.py) | _O(n)_ | _O(1)_ | Easy ||
1249 | [Minimum Remove to Make Valid Parentheses](https://leetcode.com/problems/minimum-remove-to-make-valid-parentheses/) | [C++](./C++/minimum-remove-to-make-valid-parentheses.cpp) [Python](./Python/minimum-remove-to-make-valid-parentheses.py) | _O(n)_ | _O(1)_ | Medium | | Stack
1253 | [Reconstruct a 2-Row Binary Matrix](https://leetcode.com/problems/reconstruct-a-2-row-binary-matrix/) | [C++](./C++/reconstruct-a-2-row-binary-matrix.cpp) [Python](./Python/reconstruct-a-2-row-binary-matrix.py) | _O(n)_ | _O(1)_ | Medium ||
1272 | [Remove Interval](https://leetcode.com/problems/remove-interval/) | [C++](./C++/remove-interval.cpp) [Python](./Python/remove-interval.py) | _O(n)_ | _O(1)_ | Medium || Line Sweep
1282 | [Group the People Given the Group Size They Belong To](https://leetcode.com/problems/group-the-people-given-the-group-size-they-belong-to/) | [C++](./C++/group-the-people-given-the-group-size-they-belong-to.cpp) [Python](./Python/group-the-people-given-the-group-size-they-belong-to.py) | _O(n)_ | _O(n)_ | Medium ||
1288 | [Remove Covered Intervals](https://leetcode.com/problems/remove-covered-intervals/) | [C++](./C++/remove-covered-intervals.cpp) [Python](./Python/remove-covered-intervals.py) | _O(nlogn)_ | _O(1)_ | Medium | | Line Sweep
1296 | [Divide Array in Sets of K Consecutive Numbers](https://leetcode.com/problems/divide-array-in-sets-of-k-consecutive-numbers/) | [C++](./C++/divide-array-in-sets-of-k-consecutive-numbers.cpp) [Python](./Python/divide-array-in-sets-of-k-consecutive-numbers.py) | _O(nlogn)_ | _O(n)_ | Medium ||
1326 | [Minimum Number of Taps to Open to Water a Garden](https://leetcode.com/problems/minimum-number-of-taps-to-open-to-water-a-garden/)  | [C++](./C++/minimum-number-of-taps-to-open-to-water-a-garden.cpp) [Python](./Python/minimum-number-of-taps-to-open-to-water-a-garden.py) | _O(n)_        | _O(n)_          | Hard           | variant of [Jump Game II](https://leetcode.com/problems/jump-game-ii/) |
1338 | [Reduce Array Size to The Half](https://leetcode.com/problems/reduce-array-size-to-the-half/) | [C++](./C++/reduce-array-size-to-the-half.cpp) [Python](./Python/reduce-array-size-to-the-half.py) | _O(n)_ | _O(n)_ | Medium || Counting Sort
1353 | [Maximum Number of Events That Can Be Attended](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended/)  | [C++](./C++/maximum-number-of-events-that-can-be-attended.cpp) [Python](./Python/maximum-number-of-events-that-can-be-attended.py) | _O(r + nlogn)_        | _O(n)_          | Medium           | | Heap, Sort |
1354 | [Construct Target Array With Multiple Sums](https://leetcode.com/problems/construct-target-array-with-multiple-sums/)  | [C++](./C++/construct-target-array-with-multiple-sums.cpp) [Python](./Python/construct-target-array-with-multiple-sums.py) | _O(log(max(t)) * logn)_        | _O(n)_          | Hard           | | Heap |
1386 | [Cinema Seat Allocation](https://leetcode.com/problems/cinema-seat-allocation/)  | [C++](./C++/cinema-seat-allocation.cpp) [Python](./Python/cinema-seat-allocation.py) | _O(n)_        | _O(n)_          | Medium           | | |
1400 | [Construct K Palindrome Strings](https://leetcode.com/problems/construct-k-palindrome-strings/)  | [C++](./C++/construct-k-palindrome-strings.cpp) [Python](./Python/construct-k-palindrome-strings.py) | _O(n)_        | _O(1)_          | Medium           | | |
1402 | [Reducing Dishes](https://leetcode.com/problems/reducing-dishes/)  | [C++](./C++/reducing-dishes.cpp) [Python](./Python/reducing-dishes.py) | _O(nlogn)_        | _O(1)_          | Hard           | | |
1403 | [Minimum Subsequence in Non-Increasing Order](https://leetcode.com/problems/minimum-subsequence-in-non-increasing-order/)  | [C++](./C++/minimum-subsequence-in-non-increasing-order.cpp) [Python](./Python/minimum-subsequence-in-non-increasing-order.py) | _O(nlogn)_        | _O(1)_          | Easy           | | |
1405 | [Longest Happy String](https://leetcode.com/problems/longest-happy-string/)  | [C++](./C++/longest-happy-string.cpp) [Python](./Python/longest-happy-string.py) | _O(n)_        | _O(1)_          | Medium           | | |
1414 | [Find the Minimum Number of Fibonacci Numbers Whose Sum Is K](https://leetcode.com/problems/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k/)  | [C++](./C++/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k.cpp) [Python](./Python/find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k.py) | _O(logk)_        | _O(1)_          | Medium           | | |
1419 | [Minimum Number of Frogs Croaking](https://leetcode.com/problems/minimum-number-of-frogs-croaking/)  | [C++](./C++/minimum-number-of-frogs-croaking.cpp) [Python](./Python/minimum-number-of-frogs-croaking.py) | _O(n)_        | _O(1)_          | Medium           | | |
1433 | [Check If a String Can Break Another String](https://leetcode.com/problems/check-if-a-string-can-break-another-string/)  | [C++](./C++/check-if-a-string-can-break-another-string.cpp) [Python](./Python/check-if-a-string-can-break-another-string.py) | _O(n)_        | _O(1)_          | Medium           | | |
1488 | [Avoid Flood in The City](https://leetcode.com/problems/avoid-flood-in-the-city/)  | [C++](./C++/avoid-flood-in-the-city.cpp) [Python](./Python/avoid-flood-in-the-city.py) | _O(nlogn)_        | _O(n)_          | Medium           | | |
1518 | [Water Bottles](https://leetcode.com/problems/water-bottles/)  | [C++](./C++/water-bottles.cpp) [Python](./Python/water-bottles.py) | _O(logn/logm)_        | _O(1)_          | Easy           | | |
1520 | [Maximum Number of Non-Overlapping Substrings](https://leetcode.com/problems/maximum-number-of-non-overlapping-substrings/)  | [C++](./C++/maximum-number-of-non-overlapping-substrings.cpp) [Python](./Python/maximum-number-of-non-overlapping-substrings.py) | _O(n)_        | _O(1)_          | Medium           | | |
1526 | [Minimum Number of Increments on Subarrays to Form a Target Array](https://leetcode.com/problems/minimum-number-of-increments-on-subarrays-to-form-a-target-array/)  | [C++](./C++/minimum-number-of-increments-on-subarrays-to-form-a-target-array.cpp) [Python](./Python/minimum-number-of-increments-on-subarrays-to-form-a-target-array.py) | _O(n)_        | _O(1)_          | Hard           | | |
1536 | [Minimum Swaps to Arrange a Binary Grid](https://leetcode.com/problems/minimum-swaps-to-arrange-a-binary-grid/)  | [C++](./C++/minimum-swaps-to-arrange-a-binary-grid.cpp) [Python](./Python/minimum-swaps-to-arrange-a-binary-grid.py) | _O(n^2)_        | _O(1)_          | Medium           | | |
1546 | [Maximum Number of Non-Overlapping Subarrays With Sum Equals Target](https://leetcode.com/problems/maximum-number-of-non-overlapping-subarrays-with-sum-equals-target/)| [C++](./C++/maximum-number-of-non-overlapping-subarrays-with-sum-equals-target.cpp) [Python](./Python/maximum-number-of-non-overlapping-subarrays-with-sum-equals-target.py) | _O(n)_    | _O(n)_          | Medium           ||
1564 | [Put Boxes Into the Warehouse I](https://leetcode.com/problems/put-boxes-into-the-warehouse-i/)| [C++](./C++/put-boxes-into-the-warehouse-i.cpp) [Python](./Python/put-boxes-into-the-warehouse-i.py) | _O(nlogn)_    | _O(1)_          | Medium           | 🔒 |
1567 | [Maximum Length of Subarray With Positive Product](https://leetcode.com/problems/maximum-length-of-subarray-with-positive-product/)| [C++](./C++/maximum-length-of-subarray-with-positive-product.cpp) [Python](./Python/maximum-length-of-subarray-with-positive-product.py) | _O(n)_    | _O(1)_          | Medium           ||
1568 | [Minimum Number of Days to Disconnect Island](https://leetcode.com/problems/minimum-number-of-days-to-disconnect-island/)| [C++](./C++/minimum-number-of-days-to-disconnect-island.cpp) [Python](./Python/minimum-number-of-days-to-disconnect-island.py) | _O(m^2 * n^2)_    | _O(m * n)_          | Medium           || DFS
1578 | [Minimum Deletion Cost to Avoid Repeating Letters](https://leetcode.com/problems/minimum-deletion-cost-to-avoid-repeating-letters/)| [C++](./C++/minimum-deletion-cost-to-avoid-repeating-letters.cpp) [Python](./Python/minimum-deletion-cost-to-avoid-repeating-letters.py) | _O(n)_    | _O(1)_          | Medium           ||
1580 | [Put Boxes Into the Warehouse II](https://leetcode.com/problems/put-boxes-into-the-warehouse-ii/)| [C++](./C++/put-boxes-into-the-warehouse-ii.cpp) [Python](./Python/put-boxes-into-the-warehouse-ii.py) | _O(nlogn)_    | _O(1)_          | Medium           | 🔒 |
1585 | [Check If String Is Transformable With Substring Sort Operations](https://leetcode.com/problems/check-if-string-is-transformable-with-substring-sort-operations/)| [C++](./C++/check-if-string-is-transformable-with-substring-sort-operations.cpp) [Python](./Python/check-if-string-is-transformable-with-substring-sort-operations.py) | _O(n)_    | _O(n)_          | Hard           ||
1589 | [Maximum Sum Obtained of Any Permutation](https://leetcode.com/problems/maximum-sum-obtained-of-any-permutation/)| [C++](./C++/maximum-sum-obtained-of-any-permutation.cpp) [Python](./Python/maximum-sum-obtained-of-any-permutation.py) | _O(nlogn)_    | _O(n)_          | Medium           || 
1591 | [Strange Printer II](https://leetcode.com/problems/strange-printer-ii/) | [C++](./C++/strange-printer-ii.cpp) [Python](./Python/strange-printer-ii.py) | _O(c * m * n + e)_ | _O(e)_ | Hard ||
1599 | [Maximum Profit of Operating a Centennial Wheel](https://leetcode.com/problems/maximum-profit-of-operating-a-centennial-wheel/) | [C++](./C++/maximum-profit-of-operating-a-centennial-wheel.cpp) [Python](./Python/maximum-profit-of-operating-a-centennial-wheel.py) | _O(n)_ | _O(1)_ | Medium ||
1605 | [Find Valid Matrix Given Row and Column Sums](https://leetcode.com/problems/find-valid-matrix-given-row-and-column-sums/) | [C++](./C++/find-valid-matrix-given-row-and-column-sums.cpp) [Python](./Python/find-valid-matrix-given-row-and-column-sums.py) | _O(m + n)_ | _O(1)_ | Medium ||
1616 | [Split Two Strings to Make Palindrome](https://leetcode.com/problems/split-two-strings-to-make-palindrome/) | [C++](./C++/split-two-strings-to-make-palindrome.cpp) [Python](./Python/split-two-strings-to-make-palindrome.py) | _O(n)_ | _O(1)_ | Medium || Two Pointers
1632 | [Rank Transform of a Matrix](https://leetcode.com/problems/rank-transform-of-a-matrix/) | [C++](./C++/rank-transform-of-a-matrix.cpp) [Python](./Python/rank-transform-of-a-matrix.py) | _O(m * n * log(m * n))_ | _O(m * n)_ | Hard || Union Find
1647 | [Minimum Deletions to Make Character Frequencies Unique](https://leetcode.com/problems/minimum-deletions-to-make-character-frequencies-unique/) | [C++](./C++/minimum-deletions-to-make-character-frequencies-unique.cpp) [Python](./Python/minimum-deletions-to-make-character-frequencies-unique.py) | _O(n)_ | _O(1)_ | Medium ||
1653 | [Minimum Deletions to Make String Balanced](https://leetcode.com/problems/minimum-deletions-to-make-string-balanced/) | [C++](./C++/minimum-deletions-to-make-string-balanced.cpp) [Python](./Python/minimum-deletions-to-make-string-balanced.py) | _O(n)_ | _O(1)_ | Medium ||
1663 | [Smallest String With A Given Numeric Value](https://leetcode.com/problems/smallest-string-with-a-given-numeric-value/) | [C++](./C++/smallest-string-with-a-given-numeric-value.cpp) [Python](./Python/smallest-string-with-a-given-numeric-value.py) | _O(n)_ | _O(1)_ | Medium ||
1665 | [Minimum Initial Energy to Finish Tasks](https://leetcode.com/problems/minimum-initial-energy-to-finish-tasks/) | [C++](./C++/minimum-initial-energy-to-finish-tasks.cpp) [Python](./Python/minimum-initial-energy-to-finish-tasks.py) | _O(nlogn)_ | _O(1)_ | Hard ||
1673 | [Find the Most Competitive Subsequence](https://leetcode.com/problems/find-the-most-competitive-subsequence/) | [C++](./C++/find-the-most-competitive-subsequence.cpp) [Python](./Python/find-the-most-competitive-subsequence.py) | _O(n)_ | _O(k)_ | Meidum || Stack, Greedy
1674 | [Minimum Moves to Make Array Complementary](https://leetcode.com/problems/minimum-moves-to-make-array-complementary/) | [C++](./C++/minimum-moves-to-make-array-complementary.cpp) [Python](./Python/minimum-moves-to-make-array-complementary.py) | _O(n + k)_ | _O(k)_ | Meidum ||
1686 | [Stone Game VI](https://leetcode.com/problems/stone-game-vi/) | [C++](./C++/stone-game-vi.cpp) [Python](./Python/stone-game-vi.py) | _O(nlogn)_ | _O(n)_ | Medium ||
1689 | [Partitioning Into Minimum Number Of Deci-Binary Numbers](https://leetcode.com/problems/partitioning-into-minimum-number-of-deci-binary-numbers/) | [C++](./C++/partitioning-into-minimum-number-of-deci-binary-numbers.cpp) [Python](./Python/partitioning-into-minimum-number-of-deci-binary-numbers.py) | _O(n)_ | _O(1)_ | Medium ||
1702 | [Maximum Binary String After Change](https://leetcode.com/problems/maximum-binary-string-after-change/) | [C++](./C++/maximum-binary-string-after-change.cpp) [Python](./Python/maximum-binary-string-after-change.py) | _O(n)_ | _O(1)_ | Medium ||
1705 | [Maximum Number of Eaten Apples](https://leetcode.com/problems/maximum-number-of-eaten-apples/) | [C++](./C++/maximum-number-of-eaten-apples.cpp) [Python](./Python/maximum-number-of-eaten-apples.py) | _O(nlogn)_ | _O(n)_ | Medium || Heap
1708 | [Largest Subarray Length K](https://leetcode.com/problems/largest-subarray-length-k/)| [C++](./C++/largest-subarray-length-k.cpp) [Python](./Python/largest-subarray-length-k.py)| _O(n)_ | _O(1)_ | Easy | 🔒, variant of [Last Substring in Lexicographical Order](https://leetcode.com/problems/last-substring-in-lexicographical-order/) | |
1710 | [Maximum Units on a Truck](https://leetcode.com/problems/maximum-units-on-a-truck/)| [C++](./C++/maximum-units-on-a-truck.cpp) [Python](./Python/maximum-units-on-a-truck.py)| _O(nlogn)_ | _O(1)_ | Easy | | |
1717 | [Maximum Score From Removing Substrings](https://leetcode.com/problems/maximum-score-from-removing-substrings/)| [C++](./C++/maximum-score-from-removing-substrings.cpp) [Python](./Python/maximum-score-from-removing-substrings.py)| _O(n)_ | _O(1)_ | Medium | | |
1725 | [Number Of Rectangles That Can Form The Largest Square](https://leetcode.com/problems/number-of-rectangles-that-can-form-the-largest-square/)| [C++](./C++/number-of-rectangles-that-can-form-the-largest-square.cpp) [Python](./Python/number-of-rectangles-that-can-form-the-largest-square.py)| _O(n)_ | _O(1)_ | Easy | | |
1727 | [Largest Submatrix With Rearrangements](https://leetcode.com/problems/largest-submatrix-with-rearrangements/)| [C++](./C++/largest-submatrix-with-rearrangements.cpp) [Python](./Python/largest-submatrix-with-rearrangements.py)| _O(m * nlogn)_ | _O(1)_ | Medium | | Sort |
1733 | [Minimum Number of People to Teach](https://leetcode.com/problems/minimum-number-of-people-to-teach/)| [C++](./C++/minimum-number-of-people-to-teach.cpp) [Python](./Python/minimum-number-of-people-to-teach.py)| _O(n * m^2)_ | _O(n * m)_ | Medium | | |
1736 | [Latest Time by Replacing Hidden Digits](https://leetcode.com/problems/latest-time-by-replacing-hidden-digits/)| [C++](./C++/latest-time-by-replacing-hidden-digits.cpp) [Python](./Python/latest-time-by-replacing-hidden-digits.py)| _O(1)_ | _O(1)_ | Easy | | |
1737 | [Change Minimum Characters to Satisfy One of Three Conditions](https://leetcode.com/problems/change-minimum-characters-to-satisfy-one-of-three-conditions/)| [C++](./C++/change-minimum-characters-to-satisfy-one-of-three-conditions.cpp) [Python](./Python/change-minimum-characters-to-satisfy-one-of-three-conditions.py)| _O(m + n)_ | _O(1)_ | Medium | |  Prefix Sum |
1749 | [Maximum Absolute Sum of Any Subarray](https://leetcode.com/problems/maximum-absolute-sum-of-any-subarray/)|[C++](./C++/maximum-absolute-sum-of-any-subarray.cpp) [Python](./Python/maximum-absolute-sum-of-any-subarray.py)| _O(n)_     | _O(1)_         | Medium         | variant of [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/) | Prefix Sum |
1754 | [Largest Merge Of Two Strings](https://leetcode.com/problems/largest-merge-of-two-strings/)|[C++](./C++/largest-merge-of-two-strings.cpp) [Python](./Python/largest-merge-of-two-strings.py)| _O(m * n)_     | _O(m + n)_         | Medium         |  |  |
1758 | [Minimum Changes To Make Alternating Binary String](https://leetcode.com/problems/minimum-changes-to-make-alternating-binary-string/)|[C++](./C++/minimum-changes-to-make-alternating-binary-string.cpp) [Python](./Python/minimum-changes-to-make-alternating-binary-string.py)| _O(n)_     | _O(1)_         | Easy         |  |  |
1759 | [Count Number of Homogenous Substrings](https://leetcode.com/problems/count-number-of-homogenous-substrings/)|[C++](./C++/count-number-of-homogenous-substrings.cpp) [Python](./Python/count-number-of-homogenous-substrings.py)| _O(n)_     | _O(1)_         | Medium         |  |  |
1762 | [Buildings With an Ocean View](https://leetcode.com/problems/buildings-with-an-ocean-view/)|[C++](./C++/buildings-with-an-ocean-view.cpp) [Python](./Python/buildings-with-an-ocean-view.py)| _O(n)_     | _O(1)_         | Medium         | 🔒 |  |
1764 | [Form Array by Concatenating Subarrays of Another Array](https://leetcode.com/problems/form-array-by-concatenating-subarrays-of-another-array/)|[C++](./C++/form-array-by-concatenating-subarrays-of-another-array.cpp) [Python](./Python/form-array-by-concatenating-subarrays-of-another-array.py)| _O(n)_     | _O(n)_         | Medium         |  | `KMP Algorithm` |
1769 | [Minimum Number of Operations to Move All Balls to Each Box](https://leetcode.com/problems/minimum-number-of-operations-to-move-all-balls-to-each-box/)|[C++](./C++/minimum-number-of-operations-to-move-all-balls-to-each-box.cpp) [Python](./Python/minimum-number-of-operations-to-move-all-balls-to-each-box.py)| _O(n)_     | _O(1)_         | Medium         |  | |
1775 | [Equal Sum Arrays With Minimum Number of Operations](https://leetcode.com/problems/equal-sum-arrays-with-minimum-number-of-operations/)|[C++](./C++/equal-sum-arrays-with-minimum-number-of-operations.cpp) [Python](./Python/equal-sum-arrays-with-minimum-number-of-operations.py)| _O(m + n)_     | _O(1)_         | Medium         |  | |
1785 | [Minimum Elements to Add to Form a Given Sum](https://leetcode.com/problems/minimum-elements-to-add-to-form-a-given-sum/)|[C++](./C++/minimum-elements-to-add-to-form-a-given-sum.cpp) [Python](./Python/minimum-elements-to-add-to-form-a-given-sum.py)| _O(n)_     | _O(1)_         | Medium         |  | |
1788 | [Maximize the Beauty of the Garden](https://leetcode.com/problems/maximize-the-beauty-of-the-garden/)|[C++](./C++/maximize-the-beauty-of-the-garden.cpp) [Python](./Python/maximize-the-beauty-of-the-garden.py)| _O(n)_     | _O(n)_         | Hard         | 🔒 | |
1793 | [Maximum Score of a Good Subarray](https://leetcode.com/problems/maximum-score-of-a-good-subarray/)|[C++](./C++/maximum-score-of-a-good-subarray.cpp) [Python](./Python/maximum-score-of-a-good-subarray.py)| _O(n)_     | _O(1)_         | Hard         |  | Greedy, Prefix Sum. Binary Search |
1794 | [Count Pairs of Equal Substrings With Minimum Difference](https://leetcode.com/problems/count-pairs-of-equal-substrings-with-minimum-difference/)|[C++](./C++/count-pairs-of-equal-substrings-with-minimum-difference.cpp) [Python](./Python/count-pairs-of-equal-substrings-with-minimum-difference.py)| _O(n)_     | _O(1)_         | Medium         | 🔒 | |
1798 | [Maximum Number of Consecutive Values You Can Make](https://leetcode.com/problems/maximum-number-of-consecutive-values-you-can-make/)|[C++](./C++/maximum-number-of-consecutive-values-you-can-make.cpp) [Python](./Python/maximum-number-of-consecutive-values-you-can-make.py)| _O(nlogn)_     | _O(1)_         | Medium         | | |
1801 | [Number of Orders in the Backlog](https://leetcode.com/problems/number-of-orders-in-the-backlog/)|[C++](./C++/number-of-orders-in-the-backlog.cpp) [Python](./Python/number-of-orders-in-the-backlog.py)| _O(nlogn)_     | _O(n)_         | Medium         | | Greedy, Heap |
1815 | [Maximum Number of Groups Getting Fresh Donuts](https://leetcode.com/problems/maximum-number-of-groups-getting-fresh-donuts/)|[C++](./C++/maximum-number-of-groups-getting-fresh-donuts.cpp) [Python](./Python/maximum-number-of-groups-getting-fresh-donuts.py)| _O((b/2) * (n/(b/2)+1)^(b/2))_     | _O((n/(b/2)+1)^(b/2))_         | Hard         | | Greedy, DP |
1824 | [Minimum Sideway Jumps](https://leetcode.com/problems/minimum-sideway-jumps/)|[C++](./C++/minimum-sideway-jumps.cpp) [Python](./Python/minimum-sideway-jumps.py)| _O(n)_     | _O(1)_         | Medium         | | Greedy, DP |
1827 | [Minimum Operations to Make the Array Increasing](https://leetcode.com/problems/minimum-operations-to-make-the-array-increasing/)|[C++](./C++/minimum-operations-to-make-the-array-increasing.cpp) [Python](./Python/minimum-operations-to-make-the-array-increasing.py)| _O(n)_     | _O(1)_         | Easy         | |  |
1833 | [Maximum Ice Cream Bars](https://leetcode.com/problems/minimum-operations-to-make-the-array-increasing/)|[C++](./C++/maximum-ice-cream-bars.cpp) [Python](./Python/maximum-ice-cream-bars.py)| _O(nlogn)_     | _O(1)_         | Medium         | |  |
1840 | [Maximum Building Height](https://leetcode.com/problems/maximum-building-height/)|[C++](./C++/maximum-building-height.cpp) [Python](./Python/maximum-building-height.py)| _O(nlogn)_     | _O(1)_         | Hard         | |  |
1842 | [Next Palindrome Using Same Digits](https://leetcode.com/problems/next-palindrome-using-same-digits/)|[C++](./C++/next-palindrome-using-same-digits.cpp) [Python](./Python/next-palindrome-using-same-digits.py)| _O(n)_     | _O(1)_         | Hard         | 🔒 |  |
1846 | [Maximum Element After Decreasing and Rearranging](https://leetcode.com/problems/maximum-element-after-decreasing-and-rearranging/)|[C++](./C++/maximum-element-after-decreasing-and-rearranging.cpp) [Python](./Python/maximum-element-after-decreasing-and-rearranging.py)| _O(nlogn)_     | _O(1)_         | Medium         | |  |
1850 | [Minimum Adjacent Swaps to Reach the Kth Smallest Number](https://leetcode.com/problems/minimum-adjacent-swaps-to-reach-the-kth-smallest-number/)|[C++](./C++/minimum-adjacent-swaps-to-reach-the-kth-smallest-number.cpp) [Python](./Python/minimum-adjacent-swaps-to-reach-the-kth-smallest-number.py)| _O((k + n) * n)_     | _O(n)_         | Medium         | |  |
1864 | [Minimum Number of Swaps to Make the Binary String Alternating](https://leetcode.com/problems/minimum-number-of-swaps-to-make-the-binary-string-alternating/)|[C++](./C++/minimum-number-of-swaps-to-make-the-binary-string-alternating.cpp) [Python](./Python/minimum-number-of-swaps-to-make-the-binary-string-alternating.py)| _O(n)_     | _O(1)_         | Medium         | |  |
1874 | [Minimize Product Sum of Two Arrays](https://leetcode.com/problems/minimize-product-sum-of-two-arrays/) | [C++](./C++/minimize-product-sum-of-two-arrays.cpp) [Python](./Python/minimize-product-sum-of-two-arrays.py) | _O(nlogn)_ | _O(1)_ | Medium | [GCJ2008 - Round 1A](https://codingcompetitions.withgoogle.com/codejam/round/00000000004330f6/0000000000432f33), 🔒|  |
1877 | [Minimize Maximum Pair Sum in Array](https://leetcode.com/problems/minimize-maximum-pair-sum-in-array/) | [C++](./C++/minimize-maximum-pair-sum-in-array.cpp) [Python](./Python/minimize-maximum-pair-sum-in-array.py) | _O(nlogn)_ | _O(1)_ | Medium | |  |
1881 | [Maximum Value after Insertion](https://leetcode.com/problems/maximum-value-after-insertion/) | [C++](./C++/maximum-value-after-insertion.cpp) [Python](./Python/maximum-value-after-insertion.py) | _O(n)_ | _O(1)_ | Medium | |  |
1887 | [Reduction Operations to Make the Array Elements Equal](https://leetcode.com/problems/reduction-operations-to-make-the-array-elements-equal/) | [C++](./C++/reduction-operations-to-make-the-array-elements-equal.cpp) [Python](./Python/reduction-operations-to-make-the-array-elements-equal.py) | _O(nlogn)_ | _O(1)_ | Medium | | Sort |
1893 | [Check if All the Integers in a Range Are Covered](https://leetcode.com/problems/check-if-all-the-integers-in-a-range-are-covered/) | [C++](./C++/check-if-all-the-integers-in-a-range-are-covered.cpp) [Python](./Python/check-if-all-the-integers-in-a-range-are-covered.py) | _O(n + r)_ | _O(r)_ | Easy | | Line Sweep, Sort |
1894 | [Find the Student that Will Replace the Chalk](https://leetcode.com/problems/find-the-student-that-will-replace-the-chalk/) | [C++](./C++/find-the-student-that-will-replace-the-chalk.cpp) [Python](./Python/find-the-student-that-will-replace-the-chalk.py) | _O(n)_ | _O(1)_ | Medium | | |
1897 | [Redistribute Characters to Make All Strings Equal](https://leetcode.com/problems/redistribute-characters-to-make-all-strings-equal/) | [C++](./C++/redistribute-characters-to-make-all-strings-equal.cpp) [Python](./Python/redistribute-characters-to-make-all-strings-equal.py) | _O(n)_ | _O(1)_ | Easy | | |
1899 | [Merge Triplets to Form Target Triplet](https://leetcode.com/problems/merge-triplets-to-form-target-triplet/) | [C++](./C++/merge-triplets-to-form-target-triplet.cpp) [Python](./Python/merge-triplets-to-form-target-triplet.py) | _O(n)_ | _O(1)_ | Medium | | |
1911 | [Maximum Alternating Subsequence Sum](https://leetcode.com/problems/maximum-alternating-subsequence-sum/) | [C++](./C++/maximum-alternating-subsequence-sum.cpp) [Python](./Python/maximum-alternating-subsequence-sum.py) | _O(n)_ | _O(1)_ | Medium | variant of [Best Time to Buy and Sell Stock II](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/) | |
1913 | [Maximum Product Difference Between Two Pairs](https://leetcode.com/problems/maximum-product-difference-between-two-pairs/) | [C++](./C++/maximum-product-difference-between-two-pairs.cpp) [Python](./Python/maximum-product-difference-between-two-pairs.py) | _O(n)_ | _O(1)_ | Medium | | |
1921 | [Eliminate Maximum Number of Monsters](https://leetcode.com/problems/eliminate-maximum-number-of-monsters/) | [C++](./C++/eliminate-maximum-number-of-monsters.cpp) [Python](./Python/eliminate-maximum-number-of-monsters.py) | _O(nlogn)_ | _O(1)_ | Medium | | |
1927 | [Sum Game](https://leetcode.com/problems/sum-game/) | [C++](./C++/sum-game.cpp) [Python](./Python/sum-game.py) | _O(n)_ | _O(1)_ | Medium | | |
1936 | [Add Minimum Number of Rungs](https://leetcode.com/problems/add-minimum-number-of-rungs/) | [C++](./C++/add-minimum-number-of-rungs.cpp) [Python](./Python/add-minimum-number-of-rungs.py) | _O(n)_ | _O(1)_ | Medium | | |
1946 | [Largest Number After Mutating Substring](https://leetcode.com/problems/largest-number-after-mutating-substring/) | [C++](./C++/largest-number-after-mutating-substring.cpp) [Python](./Python/largest-number-after-mutating-substring.py) | _O(n)_ | _O(1)_ | Medium | | |
1953 | [Maximum Number of Weeks for Which You Can Work](https://leetcode.com/problems/maximum-number-of-weeks-for-which-you-can-work/) | [C++](./C++/maximum-number-of-weeks-for-which-you-can-work.cpp) [Python](./Python/maximum-number-of-weeks-for-which-you-can-work.py) | _O(n)_ | _O(1)_ | Medium | | |
1975 | [Maximum Matrix Sum](https://leetcode.com/problems/maximum-matrix-sum/) | [C++](./C++/maximum-matrix-sum.cpp) [Python](./Python/maximum-matrix-sum.py) | _O(n^2)_ | _O(1)_ | Medium | | |
2027 | [Minimum Moves to Convert String](https://leetcode.com/problems/minimum-moves-to-convert-string/) | [C++](./C++/minimum-moves-to-convert-string.cpp) [Python](./Python/minimum-moves-to-convert-string.py) | _O(n)_ | _O(1)_ | Easy | | |
2030 | [Smallest K-Length Subsequence With Occurrences of a Letter](https://leetcode.com/problems/smallest-k-length-subsequence-with-occurrences-of-a-letter/) | [C++](./C++/smallest-k-length-subsequence-with-occurrences-of-a-letter.cpp) [Python](./Python/smallest-k-length-subsequence-with-occurrences-of-a-letter.py) | _O(n)_  | _O(n)_         | Hard           | | Mono Stack, Greedy
2036 | [Maximum Alternating Subarray Sum](https://leetcode.com/problems/maximum-alternating-subarray-sum/) | [C++](./C++/maximum-alternating-subarray-sum.cpp) [Python](./Python/maximum-alternating-subarray-sum.py) | _O(n)_ | _O(1)_ | Medium | variant of [Maximum Alternating Subsequence Sum](https://leetcode.com/problems/maximum-alternating-subsequence-sum/), 🔒 | Greedy, `Kadane's Algorithm`
2037 | [Minimum Number of Moves to Seat Everyone](https://leetcode.com/problems/minimum-number-of-moves-to-seat-everyone/) | [C++](./C++/minimum-number-of-moves-to-seat-everyone.cpp) [Python](./Python/minimum-number-of-moves-to-seat-everyone.py) | _O(nlogn)_ | _O(1)_ | Easy | | Greedy|
2071 | [Maximum Number of Tasks You Can Assign](https://leetcode.com/problems/maximum-number-of-tasks-you-can-assign/) | [C++](./C++/maximum-number-of-tasks-you-can-assign.cpp) [Python](./Python/maximum-number-of-tasks-you-can-assign.py) | _O(n * (logn)^2)_ | _O(n)_ | Hard | | Greedy, Binary Search, Sorted List |
2086 | [Minimum Number of Buckets Required to Collect Rainwater from Houses](https://leetcode.com/problems/minimum-number-of-buckets-required-to-collect-rainwater-from-houses/) | [C++](./C++/minimum-number-of-buckets-required-to-collect-rainwater-from-houses.cpp) [Python](./Python/minimum-number-of-buckets-required-to-collect-rainwater-from-houses.py) | _O(n)_ | _O(1)_ | Medium | | Greedy |
2087 | [Minimum Cost Homecoming of a Robot in a Grid](https://leetcode.com/problems/minimum-cost-homecoming-of-a-robot-in-a-grid/) | [C++](./C++/minimum-cost-homecoming-of-a-robot-in-a-grid.cpp) [Python](./Python/minimum-cost-homecoming-of-a-robot-in-a-grid.py) | _O(m + n)_ | _O(1)_ | Medium | | Greedy |
2126 | [Destroying Asteroids](https://leetcode.com/problems/destroying-asteroids/) | [C++](./C++/destroying-asteroids.cpp) [Python](./Python/destroying-asteroids.py) | _O(nlogn)_ | _O(1)_ | Medium | | Greedy |
2136 | [Earliest Possible Day of Full Bloom](https://leetcode.com/problems/earliest-possible-day-of-full-bloom/) | [C++](./C++/earliest-possible-day-of-full-bloom.cpp) [Python](./Python/earliest-possible-day-of-full-bloom.py) | _O(nlogn)_ | _O(n)_ | Hard | | Greedy |
2139 | [Minimum Moves to Reach Target Score](https://leetcode.com/problems/minimum-moves-to-reach-target-score/) | [C++](./C++/minimum-moves-to-reach-target-score.cpp) [Python](./Python/minimum-moves-to-reach-target-score.py) | _O(logn)_ | _O(1)_ | Medium | | |
2141 | [Maximum Running Time of N Computers](https://leetcode.com/problems/maximum-running-time-of-n-computers/) | [C++](./C++/maximum-running-time-of-n-computers.cpp) [Python](./Python/maximum-running-time-of-n-computers.py) | _O(nlogm)_ | _O(1)_ | Hard | | Greedy, Binary Search |
2144 | [Minimum Cost of Buying Candies With Discount](https://leetcode.com/problems/minimum-cost-of-buying-candies-with-discount/) | [C++](./C++/minimum-cost-of-buying-candies-with-discount.cpp) [Python](./Python/minimum-cost-of-buying-candies-with-discount.py) | _O(nlogn)_ | _O(1)_ | Easy | | Greedy, Sort |
2147 | [Number of Ways to Divide a Long Corridor](https://leetcode.com/problems/number-of-ways-to-divide-a-long-corridor/) | [C++](./C++/number-of-ways-to-divide-a-long-corridor.cpp) [Python](./Python/number-of-ways-to-divide-a-long-corridor.py) | _O(n)_ | _O(1)_ | Hard | | Greedy, Combinatorics |

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Graph
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1042 | [Flower Planting With No Adjacent](https://leetcode.com/problems/flower-planting-with-no-adjacent/) | [C++](./C++/flower-planting-with-no-adjacent.cpp) [Python](./Python/flower-planting-with-no-adjacent.py) | _O(n)_ | _O(n)_ | Easy           |||
1101 | [The Earliest Moment When Everyone Become Friends](https://leetcode.com/problems/the-earliest-moment-when-everyone-become-friends/) | [C++](./C++/the-earliest-moment-when-everyone-become-friends.cpp) [Python](./Python/the-earliest-moment-when-everyone-become-friends.py) | _O(nlogn)_ | _O(n)_ | Medium           |🔒| Union Find |
1135 | [Connecting Cities With Minimum Cost](https://leetcode.com/problems/connecting-cities-with-minimum-cost/) | [C++](./C++/connecting-cities-with-minimum-cost.cpp) [Python](./Python/connecting-cities-with-minimum-cost.py) | _O(nlogn)_ | _O(n)_ | Medium           |🔒| Union Find, `Kruskal's Algorithm`, MST |
1168 | [Optimize Water Distribution in a Village](https://leetcode.com/problems/optimize-water-distribution-in-a-village/) | [C++](./C++/optimize-water-distribution-in-a-village.cpp) [Python](./Python/optimize-water-distribution-in-a-village.py) | _O(nlogn)_ | _O(n)_ | Hard           |🔒| Union Find |
1334 | [Find the City With the Smallest Number of Neighbors at a Threshold Distance](https://leetcode.com/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance/) | [C++](./C++/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance.cpp) [Python](./Python/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance.py) | _O(n^3)_ | _O(n^2)_ | Medium           || `Floyd-Warshall Algorithm`|
1349 | [Maximum Students Taking Exam](https://leetcode.com/problems/maximum-students-taking-exam/) | [C++](./C++/maximum-students-taking-exam.cpp) [Python](./Python/maximum-students-taking-exam.py) | _O(m * n * sqrt(m * n))_ | _O(m + n)_ | Hard | [GCJ2008 - Round 3](https://codingcompetitions.withgoogle.com/codejam/round/00000000004329f5/000000000043314f) | `Hopcroft-Karp Bipartite Matching`, `Hungarian Bipartite Matching`, Maximum Independent Set |
1361 | [Validate Binary Tree Nodes](https://leetcode.com/problems/validate-binary-tree-nodes/)  | [C++](./C++/validate-binary-tree-nodes.cpp) [Python](./Python/validate-binary-tree-nodes.py) | _O(n)_| _O(n)_| Medium           || DFS, Tree | 
1462 | [Course Schedule IV](https://leetcode.com/problems/course-schedule-iv/)  | [C++](./C++/course-schedule-iv.cpp) [Python](./Python/course-schedule-iv.py) | _O(n^3)_| _O(n^2)_| Medium           || `Floyd-Warshall Algorithm` |
1489 | [Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree](https://leetcode.com/problems/find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree/)  | [C++](./C++/find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree.cpp) [Python](./Python/find-critical-and-pseudo-critical-edges-in-minimum-spanning-tree.py) | _O(nlogn)_| _O(n)_| Hard           || `Kruskal Algorithm` |
1557 | [Minimum Number of Vertices to Reach All Nodes](https://leetcode.com/problems/minimum-number-of-vertices-to-reach-all-nodes/)  | [C++](./C++/minimum-number-of-vertices-to-reach-all-nodes.cpp) [Python](./Python/minimum-number-of-vertices-to-reach-all-nodes.py) | _O(e)_| _O(n)_| Medium           ||| 
1579 | [Remove Max Number of Edges to Keep Graph Fully Traversable](https://leetcode.com/problems/remove-max-number-of-edges-to-keep-graph-fully-traversable/)  | [C++](./C++/remove-max-number-of-edges-to-keep-graph-fully-traversable.cpp) [Python](./Python/remove-max-number-of-edges-to-keep-graph-fully-traversable.py) | _O(n + m)_| _O(n)_| Hard           || Union Find | 
1584 | [Min Cost to Connect All Points](https://leetcode.com/problems/min-cost-to-connect-all-points/)  | [C++](./C++/min-cost-to-connect-all-points.cpp) [Python](./Python/min-cost-to-connect-all-points.py) | _O(n^2)_| _O(n)_| Medium           || Union Find, `Kruskal's Algorithm`, MST | 
1601 | [Maximum Number of Achievable Transfer Requests](https://leetcode.com/problems/maximum-number-of-achievable-transfer-requests/)  | [C++](./C++/maximum-number-of-achievable-transfer-requests.cpp) [Python](./Python/maximum-number-of-achievable-transfer-requests.py) | _O((n + r) * 2^r)_| _O(n + r)_| Hard           || Combinations, Backtracking | 
1615 | [Maximal Network Rank](https://leetcode.com/problems/maximal-network-rank/)  | [C++](./C++/maximal-network-rank.cpp) [Python](./Python/maximal-network-rank.py) | _O(m + n + k^2)_ | _O(m + n)_ | Medium           || Counting Sort | 
1627 | [Graph Connectivity With Threshold](https://leetcode.com/problems/graph-connectivity-with-threshold/)  | [C++](./C++/graph-connectivity-with-threshold.cpp) [Python](./Python/graph-connectivity-with-threshold.py) | _O(nlogn + q)_| _O(n)_| Hard           || Union Find, Math | 
1631 | [Path With Minimum Effort](https://leetcode.com/problems/path-with-minimum-effort/)  | [C++](./C++/path-with-minimum-effort.cpp) [Python](./Python/path-with-minimum-effort.py) | _O(m * n * log(m * n))_| _O(m * n)_| Medium           || Binary Search, DFS, BFS, Bi-BFS, Union Find, `Dijkstra's Algorithm` | 
1697 | [Checking Existence of Edge Length Limited Paths](https://leetcode.com/problems/checking-existence-of-edge-length-limited-paths/)  | [C++](./C++/checking-existence-of-edge-length-limited-paths.cpp) [Python](./Python/checking-existence-of-edge-length-limited-paths.py) | _O(nlogn + mlogm)_| _O(n)_| Hard           || Union Find | 
1719 | [Number Of Ways To Reconstruct A Tree](https://leetcode.com/problems/number-of-ways-to-reconstruct-a-tree/)  | [C++](./C++/number-of-ways-to-reconstruct-a-tree.cpp) [Python](./Python/number-of-ways-to-reconstruct-a-tree.py) | _O(nlogn)_| _O(n)_| Hard           ||| 
1724 | [Checking Existence of Edge Length Limited Paths II](https://leetcode.com/problems/checking-existence-of-edge-length-limited-paths-ii/)  | [C++](./C++/checking-existence-of-edge-length-limited-paths-ii.cpp) [Python](./Python/checking-existence-of-edge-length-limited-paths-ii.py) | ctor: _O(nlogn + mlogm)_<br>query: _O(logn)_ | _O(nlogn + m)_| Hard           |🔒| Versioned Union Find, Binary Lifting | 
1743 | [Restore the Array From Adjacent Pairs](https://leetcode.com/problems/restore-the-array-from-adjacent-pairs/)  | [C++](./C++/restore-the-array-from-adjacent-pairs.cpp) [Python](./Python/restore-the-array-from-adjacent-pairs.py) | _O(n)_| _O(n)_| Medium           ||| 
1761 | [Minimum Degree of a Connected Trio in a Graph](https://leetcode.com/problems/minimum-degree-of-a-connected-trio-in-a-graph/)  | [C++](./C++/minimum-degree-of-a-connected-trio-in-a-graph.cpp) [Python](./Python/minimum-degree-of-a-connected-trio-in-a-graph.py) | _O(n^3)_| _O(n^2)_| Hard           ||| 
1778 | [Shortest Path in a Hidden Grid](https://leetcode.com/problems/shortest-path-in-a-hidden-grid/)  | [C++](./C++/shortest-path-in-a-hidden-grid.cpp) [Python](./Python/shortest-path-in-a-hidden-grid.py) | _O(m * n)_ | _O(m * n)_| Medium           |🔒| DFS, BFS, Bi-BFS | 
1782 | [Count Pairs Of Nodes](https://leetcode.com/problems/count-pairs-of-nodes/)  | [C++](./C++/count-pairs-of-nodes.cpp) [Python](./Python/count-pairs-of-nodes.py) | _O(n + e + q)_ | _O(n + e)_| Hard           || Counting, Two Pointers | 
1786 | [Number of Restricted Paths From First to Last Node](https://leetcode.com/problems/number-of-restricted-paths-from-first-to-last-node/)  | [C++](./C++/number-of-restricted-paths-from-first-to-last-node.cpp) [Python](./Python/number-of-restricted-paths-from-first-to-last-node.py) | _O(\|E\| * log\|V\|)_ | _O(\|E\|)_ | Medium | | `Dijkstra's Algorithm`, DP |
1791 | [Find Center of Star Graph](https://leetcode.com/problems/find-center-of-star-graph/)  | [C++](./C++/find-center-of-star-graph.cpp) [Python](./Python/find-center-of-star-graph.py) | _O(n)_| _O(n)_| Medium           ||| 
1810 | [Minimum Path Cost in a Hidden Grid](https://leetcode.com/problems/minimum-path-cost-in-a-hidden-grid/)  | [C++](./C++/minimum-path-cost-in-a-hidden-grid.cpp) [Python](./Python/minimum-path-cost-in-a-hidden-grid.py) | _O(m * n * log(m * n))_ | _O(m * n)_| Medium           |🔒| DFS, `Dijkstra's Algorithm`| 
1820 | [Maximum Number of Accepted Invitations](https://leetcode.com/problems/maximum-number-of-accepted-invitations/) | [C++](./C++/maximum-number-of-accepted-invitations.cpp) [Python](./Python/maximum-number-of-accepted-invitations.py) | _O(m * n * sqrt(m + n))_ | _O(m + n)_ | Medium | 🔒 | `Hopcroft-Karp Bipartite Matching`, `Hungarian Bipartite Matching` |
1879 | [Minimum XOR Sum of Two Arrays](https://leetcode.com/problems/minimum-xor-sum-of-two-arrays/) | [C++](./C++/minimum-xor-sum-of-two-arrays.cpp) [Python](./Python/minimum-xor-sum-of-two-arrays.py) | _O(n^3)_ | _O(n^2)_ | Hard | | DP, `Hungarian Weighted Bipartite Matching` |
1947 | [Maximum Compatibility Score Sum](https://leetcode.com/problems/maximum-compatibility-score-sum/) | [C++](./C++/maximum-compatibility-score-sum.cpp) [Python](./Python/maximum-compatibility-score-sum.py) | _O(m^2 * (n + m))_ | _O(m^2)_ | Medium | variant of [Minimum XOR Sum of Two Arrays](https://leetcode.com/problems/minimum-xor-sum-of-two-arrays/) | DP, `Hungarian Weighted Bipartite Matching` |
1971 | [Find if Path Exists in Graph](https://leetcode.com/problems/find-if-path-exists-in-graph/)  | [C++](./C++/find-if-path-exists-in-graph.cpp) [Python](./Python/find-if-path-exists-in-graph.py) | _O(\|V\| + \|E\|)_| _O(\|V\| + \|E\|)_| Easy           || DFS, BFS, Bi-BFS| 
1976 | [Number of Ways to Arrive at Destination](https://leetcode.com/problems/number-of-ways-to-arrive-at-destination/)  | [C++](./C++/number-of-ways-to-arrive-at-destination.cpp) [Python](./Python/number-of-ways-to-arrive-at-destination.py) | _O(\|E\| * log\|V\|)_ | _O(\|E\|)_ | Medium | | `Dijkstra's Algorithm` |
2076 | [Process Restricted Friend Requests](https://leetcode.com/problems/process-restricted-friend-requests/)  | [C++](./C++/process-restricted-friend-requests.cpp) [Python](./Python/process-restricted-friend-requests.py) | _O(n * r)_ | _O(n)_ | Hard | | Union Find |
2077 | [Paths in Maze That Lead to Same Room](https://leetcode.com/problems/paths-in-maze-that-lead-to-same-room/)  | [C++](./C++/paths-in-maze-that-lead-to-same-room.cpp) [Python](./Python/paths-in-maze-that-lead-to-same-room.py) | _O(\|V\|^3)_ | _O(\|E\|)_ | Medium | 🔒 | |
2092 | [Find All People With Secret](https://leetcode.com/problems/find-all-people-with-secret/)  | [C++](./C++/find-all-people-with-secret.cpp) [Python](./Python/find-all-people-with-secret.py) | _O(nlogn)_ | _O(nlogn)_ | Hard | | BFS, DFS, Union Find |
2093 | [Minimum Path Cost in a Hidden Grid](https://leetcode.com/problems/minimum-cost-to-reach-city-with-discounts/)  | [C++](./C++/minimum-cost-to-reach-city-with-discounts.cpp) [Python](./Python/minimum-cost-to-reach-city-with-discounts.py) | _O(\|E\| * log\|V\|)_ | _O(\|V\| + \|E\|)_ | Medium           | variant of [Cheapest Flights Within K Stops](https://leetcode.com/problems/cheapest-flights-within-k-stops/), 🔒 | `Dijkstra's Algorithm`, DP | 
2097 | [Valid Arrangement of Pairs](https://leetcode.com/problems/valid-arrangement-of-pairs/) | [C++](./C++/valid-arrangement-of-pairs.cpp)  [Python](./Python/valid-arrangement-of-pairs.py)  |  _O(\|V\| + \|E\|)_ | _O(\|V\| + \|E\|)_ | Hard | variant of [Reconstruct Itinerary](https://leetcode.com/problems/reconstruct-itinerary/) | `Hierholzer's Algorithm` |
2123 | [Minimum Operations to Remove Adjacent Ones in Matrix](https://leetcode.com/problems/minimum-operations-to-remove-adjacent-ones-in-matrix/) | [C++](./C++/minimum-operations-to-remove-adjacent-ones-in-matrix.cpp) [Python](./Python/minimum-operations-to-remove-adjacent-ones-in-matrix.py) | _O(m * n * sqrt(m * n))_ | _O(m + n)_ | Hard | variant of [Maximum Students Taking Exam](https://leetcode.com/problems/maximum-students-taking-exam/), 🔒 | `Hopcroft-Karp Bipartite Matching`, Maximum Independent Set |
2127 | [Maximum Employees to Be Invited to a Meeting](https://leetcode.com/problems/maximum-employees-to-be-invited-to-a-meeting/) | [C++](./C++/maximum-employees-to-be-invited-to-a-meeting.cpp) [Python](./Python/maximum-employees-to-be-invited-to-a-meeting.py) | _O(n)_ | _O(n)_ | Hard |  |  |

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## Geometry
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1453 | [Maximum Number of Darts Inside of a Circular Dartboard](https://leetcode.com/problems/maximum-number-of-darts-inside-of-a-circular-dartboard/)  | [C++](./C++/maximum-number-of-darts-inside-of-a-circular-dartboard.cpp) [Python](./Python/maximum-number-of-darts-inside-of-a-circular-dartboard.py) | _O(n^2 * logn)_| _O(n)_| Hard           || Line Sweep |
1515 | [Best Position for a Service Centre](https://leetcode.com/problems/best-position-for-a-service-centre/)  | [C++](./C++/best-position-for-a-service-centre.cpp) [Python](./Python/best-position-for-a-service-centre.py) | _O(n * iter)_| _O(n)_| Hard           || Geometric Median, Gradient Descent, Weiszfeld's Algorithm |
1610 | [Maximum Number of Visible Points](https://leetcode.com/problems/maximum-number-of-visible-points/)  | [C++](./C++/maximum-number-of-visible-points.cpp) [Python](./Python/maximum-number-of-visible-points.py) | _O(nlogn)_| _O(n)_| Hard           || Two Pointers, Sliding Window |
1924 | [Erect the Fence II](https://leetcode.com/problems/erect-the-fence-ii/)  | [C++](./C++/erect-the-fence-ii.cpp) [Python](./Python/erect-the-fence-ii.py) | _O(n)_ on average | _O(n)_| Hard           | 🔒 | `Welzl's Algorithm` | 
1956 | [Minimum Time For K Virus Variants to Spread](https://leetcode.com/problems/minimum-time-for-k-virus-variants-to-spread/) | [C++](./C++/minimum-time-for-k-virus-variants-to-spread.cpp) [Python](./Python/minimum-time-for-k-virus-variants-to-spread.py) | _O(nlogn * logr)_ | _O(n)_ | Hard | 🔒 | Geometry, Binary Search, Line Sweep, Segment Tree, Coordinate Compression
2101 | [Detonate the Maximum Bombs](https://leetcode.com/problems/detonate-the-maximum-bombs/) | [C++](./C++/detonate-the-maximum-bombs.cpp) [Python](./Python/detonate-the-maximum-bombs.py) | _O(\|V\|^2 + \V\| * \|E\|)_ | _O(\V\| + \|E\|)_ | Medium | | Graph, DFS, BFS

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## Simulation
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1138 | [Alphabet Board Path](https://leetcode.com/problems/alphabet-board-path/)  | [C++](./C++/alphabet-board-path.cpp) [Python](./Python/alphabet-board-path.py) | _O(n)_| _O(1)_| Medium           ||| 
1243 | [Array Transformation](https://leetcode.com/problems/array-transformation/) | [C++](./C++/array-transformation.cpp) [Python](./Python/array-transformation.py) | _O(n^2)_ | _O(n)_ | Easy           ||| 
2061 | [Number of Spaces Cleaning Robot Cleaned](https://leetcode.com/problems/number-of-spaces-cleaning-robot-cleaned/) | [C++](./C++/number-of-spaces-cleaning-robot-cleaned.cpp) [Python](./Python/number-of-spaces-cleaning-robot-cleaned.py) | _O(m * n)_ | _O(1)_ | Medium           |🔒|| 

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## Design
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1146 | [Snapshot Array](https://leetcode.com/problems/snapshot-array/) | [C++](./C++/snapshot-array.cpp) [Python](./Python/snapshot-array.py) | set: _O(1)_<br> get: _O(logn)_ | _O(n)_ | Medium |||
1166 | [Design File System](https://leetcode.com/problems/design-file-system/) | [C++](./C++/design-file-system.cpp) [Python](./Python/design-file-system.py) | create: _O(n)_<br>get: _O(n)_ | _O(n)_ | Medium |🔒| |
1172 | [Dinner Plate Stacks](https://leetcode.com/problems/dinner-plate-stacks/) | [C++](./C++/dinner-plate-stacks.cpp) [Python](./Python/dinner-plate-stacks.py) | push: _O(logn)_<br>pop: _O(1)_, amortized<br>popAtStack: _(logn)_ | _O(n * c)_ | Hard | | |
1206 | [Design Skiplist](https://leetcode.com/problems/design-skiplist/) | [C++](./C++/design-skiplist.cpp) [Python](./Python/design-skiplist.py) | _O(logn)_, on average | _O(n)_ | Hard | | |
1236 | [Web Crawler](https://leetcode.com/problems/web-crawler/) | [C++](./C++/web-crawler.cpp) [Python](./Python/web-crawler.py) | _O(\|V\| + \|E\|)_ | _O(\|V\|)_ | Medium |🔒| BFS, DFS |
1244 | [Design A Leaderboard](https://leetcode.com/problems/design-a-leaderboard/) | [C++](./C++/design-a-leaderboard.cpp) [Python](./Python/design-a-leaderboard.py) | ctor: _O(1)_<br> add: _O(1)_<br> top: _O(n)_<br> reset: _O(1)_ | _O(n)_ | Medium | | |
1268 | [Search Suggestions System](https://leetcode.com/problems/search-suggestions-system/) | [C++](./C++/search-suggestions-system.cpp) [Python](./Python/search-suggestions-system.py) | ctor: _O(n * l)_<br> suggest: _O(l^2)_ | _O(t)_ | Medium ||  Trie |
1286 | [Iterator for Combination](https://leetcode.com/problems/iterator-for-combination/) | [C++](./C++/iterator-for-combination.cpp) [Python](./Python/iterator-for-combination.py) | _O(k)_ | _O(k)_ | Medium ||  Stack |
1348 | [Tweet Counts Per Frequency](https://leetcode.com/problems/tweet-counts-per-frequency/) | [C++](./C++/tweet-counts-per-frequency.cpp) [Python](./Python/tweet-counts-per-frequency.py) | add: _O(logn)_<br>query: _O(c)_ | _O(n)_ | Medium |||
1352 | [Product of the Last K Numbers](https://leetcode.com/problems/product-of-the-last-k-numbers/) | [C++](./C++/product-of-the-last-k-numbers.cpp) [Python](./Python/product-of-the-last-k-numbers.py) | ctor: _O(1)_<br>add: _O(1)_<br>get: _O(1)_ | _O(n)_ | Medium |||
1357 | [Apply Discount Every n Orders](https://leetcode.com/problems/apply-discount-every-n-orders/) | [C++](./C++/apply-discount-every-n-orders.cpp) [Python](./Python/apply-discount-every-n-orders.py) | ctor: _O(m)_<br>getBill: _O(p)_ | _O(m)_ | Medium |||
1381 | [Design a Stack With Increment Operation](https://leetcode.com/problems/design-a-stack-with-increment-operation/) | [C++](./C++/design-a-stack-with-increment-operation.cpp) [Python](./Python/design-a-stack-with-increment-operation.py) | ctor: _O(1)_<br>push: _O(1)_<br>pop: _O(1)_<br>increment: _O(1)_ | _O(n)_ | Medium |||
1396 | [Design Underground System](https://leetcode.com/problems/design-underground-system/) | [C++](./C++/design-underground-system.cpp) [Python](./Python/design-underground-system.py) | ctor: _O(1)_<br>checkin: _O(1)_<br>checkout: _O(1)_<br>getaverage: _O(1)_ | _O(n)_ | Medium |||
1429 | [First Unique Number](https://leetcode.com/problems/first-unique-number/)| [C++](./C++/first-unique-number.cpp) [Python](./Python/first-unique-number.py) | ctor: _O(k)_<br>add: _O(1)_<br>showFirstUnique: _O(1)_ | _O(n)_ | Medium | 🔒 | LinkedHashSet 
1472 | [Design Browser History](https://leetcode.com/problems/design-browser-history/) | [C++](./C++/design-browser-history.cpp) [Python](./Python/design-browser-history.py) | ctor: _O(1)_<br>visit: _O(1)_<br>back: _O(1)_<br>forward: _O(1)_ | _O(n)_ | Medium |||
1476 | [Subrectangle Queries](https://leetcode.com/problems/subrectangle-queries/) | [C++](./C++/subrectangle-queries.cpp) [Python](./Python/subrectangle-queries.py) | ctor: _O(1)_<br>update: _O(1)_<br>get: _O(u)_ | _O(u)_ | Medium |||
1483 | [Kth Ancestor of a Tree Node](https://leetcode.com/problems/kth-ancestor-of-a-tree-node/) | [C++](./C++/kth-ancestor-of-a-tree-node.cpp) [Python](./Python/kth-ancestor-of-a-tree-node.py) | ctor: _O(n * logh)_<br>get: _O(logh)_ | _O(n * logh)_ | Hard || DP, Binary Lifting |
1500 | [Design a File Sharing System](https://leetcode.com/problems/design-a-file-sharing-system/) | [C++](./C++/design-a-file-sharing-system.cpp) [Python](./Python/design-a-file-sharing-system.py) | ctor: _O(1)_<br>join: _O(logu + c)_<br>leave: _O(logu + c)_<br>request: _O(u)_ | _O(u * c)_ | Medium | 🔒 | |
1570 | [Dot Product of Two Sparse Vectors](https://leetcode.com/problems/dot-product-of-two-sparse-vectors/) | [C++](./C++/dot-product-of-two-sparse-vectors.cpp) [Python](./Python/dot-product-of-two-sparse-vectors.py) | ctor: _O(n)_<br>dot_product: _O(min(n, m))_ | _O(n)_ | Medium | 🔒 | |
1586 | [Binary Search Tree Iterator II](https://leetcode.com/problems/binary-search-tree-iterator-ii/) | [C++](./C++/binary-search-tree-iterator-ii.cpp) [Python](./Python/binary-search-tree-iterator-ii.py) | _O(1)_, amortized | _O(h)_| Medium | 🔒 |   
1600 | [Throne Inheritance](https://leetcode.com/problems/throne-inheritance/) | [C++](./C++/throne-inheritance.cpp) [Python](./Python/throne-inheritance.py) | ctor: _O(1)_<br>birth: _O(1)_<br>death: _O(1)_<br>inherit: _O(n)_ | _O(n)_| Medium | |  
1603 | [Design Parking System](https://leetcode.com/problems/design-parking-system/) | [C++](./C++/design-parking-system.cpp) [Python](./Python/design-parking-system.py) | _O(1)_ | _O(1)_| Easy | | 
1622 | [Fancy Sequence](https://leetcode.com/problems/fancy-sequence/) | [C++](./C++/fancy-sequence.cpp) [Python](./Python/fancy-sequence.py) | _O(1)_ | _O(n)_| Hard | |  `Euler's Theorem`
1628 | [Design an Expression Tree With Evaluate Function](https://leetcode.com/problems/design-an-expression-tree-with-evaluate-function/) | [C++](./C++/design-an-expression-tree-with-evaluate-function.cpp) [Python](./Python/design-an-expression-tree-with-evaluate-function.py) | _O(n)_ | _O(h)_| Medium | 🔒 |
1656 | [Design an Ordered Stream](https://leetcode.com/problems/design-an-ordered-stream/) | [C++](./C++/design-an-ordered-stream.cpp) [Python](./Python/design-an-ordered-stream.py) | _O(1)_, amortized | _O(n)_| Easy | |
1670 | [Design Front Middle Back Queue](https://leetcode.com/problems/design-front-middle-back-queue/) | [C++](./C++/design-front-middle-back-queue.cpp) [Python](./Python/design-front-middle-back-queue.py) | _O(1)_ | _O(n)_| Medium | |
1756 | [Design Most Recently Used Queue](https://leetcode.com/problems/design-most-recently-used-queue/) | [C++](./C++/design-most-recently-used-queue.cpp) [Python](./Python/design-most-recently-used-queue.py) | ctor: _O(nlogn)_<br>fetch: _O(logn)_ | _O(n)_| Medium | 🔒 | Sorted List, BIT, Fenwick Tree, Square Root Decomposition
1797 | [Design Authentication Manager](https://leetcode.com/problems/design-authentication-manager/) | [C++](./C++/design-authentication-manager.cpp) [Python](./Python/design-authentication-manager.py) | ctor: _O(1)_<br>generate: _O(1)_, amortized<br>renew: _O(1)_, amortized<br>count: _O(1)_, amortized | _O(n)_| Medium | | OrderedDict
1804 | [Implement Trie II (Prefix Tree)](https://leetcode.com/problems/implement-trie-ii-prefix-tree/) | [C++](./C++/implement-trie-ii-prefix-tree.cpp) [Python](./Python/implement-trie-ii-prefix-tree.py) | ctor: _O(1)_<br>insert: _O(n)_<br>count_word: _O(n)_<br>count_prefix: _O(n)_<br>erase: _O(n)_ | _O(t)_| Medium | 🔒 | Trie
1825 | [Finding MK Average](https://leetcode.com/problems/finding-mk-average/) | [C++](./C++/finding-mk-average.cpp) [Python](./Python/finding-mk-average.py) | ctor: _O(1)_<br>add_element: _O(logn)_<br>calc_mkaverge: _O(1)_ | _O(m)_| Hard | | Sorted List
1845 | [Seat Reservation Manager](https://leetcode.com/problems/seat-reservation-manager/) | [C++](./C++/seat-reservation-manager.cpp) [Python](./Python/seat-reservation-manager.py) | ctor: _O(n)_<br>reserve: _O(logn)_<br>unreserve: _O(logn)_ | _O(n)_| Medium | | Heap
1865 | [Finding Pairs With a Certain Sum](https://leetcode.com/problems/finding-pairs-with-a-certain-sum/) | [C++](./C++/finding-pairs-with-a-certain-sum.cpp) [Python](./Python/finding-pairs-with-a-certain-sum.py) | ctor: _O(n1 + n2)_<br>add: _O(1)_<br>count: _O(n1)_ | _O(n1 + n2)_| Medium | | Hash Table
1912 | [Design Movie Rental System](https://leetcode.com/problems/design-movie-rental-system/) | [C++](./C++/design-movie-rental-system.cpp) [Python](./Python/design-movie-rental-system.py) | ctor: _O(nlogn)_<br>search: _O(logn)_<br>rent: _O(logn)_<br>drop: _O(logn)_<br>report: _O(logn)_ | _O(n)_| Hard | | Ordered List
1993 | [Operations on Tree](https://leetcode.com/problems/operations-on-tree/) | [C++](./C++/operations-on-tree.cpp) [Python](./Python/operations-on-tree.py) | ctor: _O(n)_<br>lock: _O(1)_<br>unlock: _O(1)_<br>upgrade: _O(n)_ | _O(n)_| Medium | |
2013 | [Detect Squares](https://leetcode.com/problems/detect-squares/) | [C++](./C++/detect-squares.cpp) [Python](./Python/detect-squares.py) | ctor: _O(1)_<br>add: _O(1)_<br>count: _O(n)_ | _O(n)_| Medium | |
2034 | [Stock Price Fluctuation](https://leetcode.com/problems/stock-price-fluctuation/) | [C++](./C++/stock-price-fluctuation.cpp) [Python](./Python/stock-price-fluctuation.py) | ctor: _O(1)_<br>update: _O(logn)_<br>current: _O(1)_<br>max: _O(1)_<br>min: _O(1)_ | _O(n)_ | Medium | | Sorted List, Heap
2043 | [Simple Bank System](https://leetcode.com/problems/simple-bank-system/) | [C++](./C++/simple-bank-system.cpp) [Python](./Python/simple-bank-system.py) | ctor: _O(1)_<br>transer: _O(1)_<br>deposit: _O(1)_<br>withdraw: _O(1)_ | _O(1)_ | Medium | |
2069 | [Walking Robot Simulation II](https://leetcode.com/problems/walking-robot-simulation-ii/) | [C++](./C++/walking-robot-simulation-ii.cpp) [Python](./Python/walking-robot-simulation-ii.py) | _O(1)_ | _O(1)_ | Medium | | Simulation, Math
2080 | [Range Frequency Queries](https://leetcode.com/problems/range-frequency-queries/) | [C++](./C++/range-frequency-queries.cpp) [Python](./Python/range-frequency-queries.py) | ctor: _O(n)_<br>query: _O(logn)_ | _O(n)_ | Medium | | Binary Search
2102 | [Sequentially Ordinal Rank Tracker](https://leetcode.com/problems/sequentially-ordinal-rank-tracker/) | [C++](./C++/sequentially-ordinal-rank-tracker.cpp) [Python](./Python/sequentially-ordinal-rank-tracker.py) | add: _O(logn)_<br>get: _O(logn)_ | _O(n)_ | Hard | | Sorted List

<br/>
<div align="right">
    <b><a href="#algorithms">⬆️ Back to Top</a></b>
</div>
<br/>

## Concurrency
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1114 | [Print in Order](https://leetcode.com/problems/print-in-order/)     | [C++](./C++/print-in-order.cpp) [Python](./Python/print-in-order.py)  | _O(n)_ | _O(1)_ | Easy ||
1115 | [Print FooBar Alternately](https://leetcode.com/problems/print-foobar-alternately/)     | [C++](./C++/print-foobar-alternately.cpp) [Python](./Python/print-foobar-alternately.py)  | _O(n)_ | _O(1)_ | Medium ||
1116 | [Print Zero Even Odd](https://leetcode.com/problems/print-zero-even-odd/)| [C++](./C++/print-zero-even-odd.cpp) [Python](./Python/print-zero-even-odd.py) | _O(n)_ | _O(1)_ | Medium ||
1117 | [Building H2O](https://leetcode.com/problems/building-h2o/) | [C++](./C++/building-h2o.cpp) [Python](./Python/building-h2o.py) | _O(n)_ | _O(1)_| Hard |||
1188 | [Design Bounded Blocking Queue](https://leetcode.com/problems/design-bounded-blocking-queue/) | [C++](./C++/design-bounded-blocking-queue.cpp) [Python](./Python/design-bounded-blocking-queue.py) | _O(n)_ | _O(1)_| Medium | 🔒 ||
1195 | [Fizz Buzz Multithreaded](https://leetcode.com/problems/fizz-buzz-multithreaded/)| [C++](./C++/fizz-buzz-multithreaded.cpp) [Python](./Python/fizz-buzz-multithreaded.py) | _O(n)_ | _O(1)_ | Medium ||
1226 | [The Dining Philosophers](https://leetcode.com/problems/the-dining-philosophers/)| [C++](./C++/the-dining-philosophers.cpp) [Python](./Python/the-dining-philosophers.py) | _O(n)_ | _O(1)_ | Medium ||
1242 | [Web Crawler Multithreaded](https://leetcode.com/problems/web-crawler-multithreaded/)| [C++](./C++/web-crawler-multithreaded.cpp) [Python](./Python/web-crawler-multithreaded.py) |  _O(\|V\| + \|E\|)_ | _O(\|V\|)_ | Medium |🔒| | BFS, DFS |
1279 | [Traffic Light Controlled Intersection](https://leetcode.com/problems/traffic-light-controlled-intersection/)| [C++](./C++/traffic-light-controlled-intersection.cpp) [Python](./Python/traffic-light-controlled-intersection.py) |  _O(n)_ | _O(1)_ | Easy |🔒| | |

<br/>
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</div>
<br/>

## SQL
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
1045 | [Customers Who Bought All Products](https://leetcode.com/problems/customers-who-bought-all-products/) | [MySQL](./MySQL/customers-who-bought-all-products.sql) | _O(n + k)_ | _O(n + k)_       | Medium           |🔒| |
1050 | [Actors and Directors Who Cooperated At Least Three Times](https://leetcode.com/problems/actors-and-directors-who-cooperated-at-least-three-times/) | [MySQL](./MySQL/actors-and-directors-who-cooperated-at-least-three-times.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1068 | [Product Sales Analysis I](https://leetcode.com/problems/product-sales-analysis-i/) | [MySQL](./MySQL/product-sales-analysis-i.sql) | _O(m + n)_ | _O(m + n)_       | Easy           |🔒| |
1069 | [Product Sales Analysis II](https://leetcode.com/problems/product-sales-analysis-ii/) | [MySQL](./MySQL/product-sales-analysis-ii.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1070 | [Product Sales Analysis III](https://leetcode.com/problems/product-sales-analysis-iii/) | [MySQL](./MySQL/product-sales-analysis-iii.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1075 | [Project Employees I](https://leetcode.com/problems/project-employees-i/) | [MySQL](./MySQL/project-employees-i.sql) | _O(m + n)_ | _O(m + n)_       | Easy           |🔒| |
1076 | [Project Employees II](https://leetcode.com/problems/project-employees-ii/) | [MySQL](./MySQL/project-employees-ii.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1077 | [Project Employees III](https://leetcode.com/problems/project-employees-iii/) | [MySQL](./MySQL/project-employees-iii.sql) | _O((m + n)^2)_ | _O(m + n)_       | Medium           |🔒| |
1082 | [Sales Analysis I](https://leetcode.com/problems/sales-analysis-i/) | [MySQL](./MySQL/sales-analysis-i.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1083 | [Sales Analysis II](https://leetcode.com/problems/sales-analysis-ii/) | [MySQL](./MySQL/sales-analysis-ii.sql) | _O(m + n)_ | _O(m + n)_       | Easy           |🔒| |
1084 | [Sales Analysis III](https://leetcode.com/problems/sales-analysis-iii/) | [MySQL](./MySQL/sales-analysis-iii.sql) | _O(m + n)_ | _O(m + n)_       | Easy           |🔒| |
1097 | [Game Play Analysis V](https://leetcode.com/problems/game-play-analysis-v/) | [MySQL](./MySQL/game-play-analysis-v.sql) | _O(n^2)_ | _O(n)_       | Hard           |🔒| |
1098 | [Unpopular Books](https://leetcode.com/problems/unpopular-books/) | [MySQL](./MySQL/unpopular-books.sql) | _O(m + n)_ | _O(n)_       | Medium           |🔒| |
1107 | [New Users Daily Count](https://leetcode.com/problems/new-users-daily-count/) | [MySQL](./MySQL/new-users-daily-count.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1112 | [Highest Grade For Each Student](https://leetcode.com/problems/highest-grade-for-each-student/) | [MySQL](./MySQL/highest-grade-for-each-student.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1113 | [Reported Posts](https://leetcode.com/problems/reported-posts/) | [MySQL](./MySQL/reported-posts.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1126 | [Active Businesses](https://leetcode.com/problems/active-businesses/) | [MySQL](./MySQL/active-businesses.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1127 | [User Purchase Platform](https://leetcode.com/problems//user-purchase-platform/) | [MySQL](./MySQL//user-purchase-platform.sql) | _O(n)_ | _O(n)_       | Hard           |🔒| |
1132 | [Reported Posts II](https://leetcode.com/problems/reported-posts-ii/) | [MySQL](./MySQL/reported-posts-ii.sql) | _O(m + n)_ | _O(n)_       | Medium           |🔒| |
1141 | [User Activity for the Past 30 Days I](https://leetcode.com/problems/user-activity-for-the-past-30-days-i/) | [MySQL](./MySQL/user-activity-for-the-past-30-days-i.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1142 | [User Activity for the Past 30 Days II](https://leetcode.com/problems/user-activity-for-the-past-30-days-ii/) | [MySQL](./MySQL/user-activity-for-the-past-30-days-ii.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1148 | [Article Views I](https://leetcode.com/problems/article-views-i/) | [MySQL](./MySQL/article-views-i.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒| |
1149 | [Article Views II](https://leetcode.com/problems/article-views-ii/) | [MySQL](./MySQL/article-views-ii.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1158 | [Market Analysis I](https://leetcode.com/problems/market-analysis-i/) | [MySQL](./MySQL/market-analysis-i.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒| |
1159 | [Market Analysis II](https://leetcode.com/problems/market-analysis-ii/) | [MySQL](./MySQL/market-analysis-ii.sql) | _O(m + n)_ | _O(m + n)_       | Hard           |🔒| |
1164 | [Product Price at a Given Date](https://leetcode.com/problems/product-price-at-a-given-date/) | [MySQL](./MySQL/product-price-at-a-given-date.sql) | _O(mlogn)_ | _O(m)_       | Medium           |🔒| |
1173 | [Immediate Food Delivery I](https://leetcode.com/problems/immediate-food-delivery-i/) | [MySQL](./MySQL/immediate-food-delivery-i.sql) | _O(n)_ | _O(1)_       | Easy           |🔒| |
1174 | [Immediate Food Delivery II](https://leetcode.com/problems/immediate-food-delivery-ii/) | [MySQL](./MySQL/immediate-food-delivery-ii.sql) | _O(n)_ | _O(m)_       | Medium           |🔒| |
1179 | [Reformat Department Table](https://leetcode.com/problems/reformat-department-table/) | [MySQL](./MySQL/reformat-department-table.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1193 | [Monthly Transactions I](https://leetcode.com/problems/monthly-transactions-i/) | [MySQL](./MySQL/monthly-transactions-i.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1194 | [Tournament Winners](https://leetcode.com/problems/tournament-winners/) | [MySQL](./MySQL/tournament-winners.sql) | _O(m + n + nlogn)_ | _O(m + n)_       | Hard           |🔒| |
1204 | [Last Person to Fit in the Elevator](https://leetcode.com/problems/last-person-to-fit-in-the-elevator/) | [MySQL](./MySQL/last-person-to-fit-in-the-elevator.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1205 | [Monthly Transactions II](https://leetcode.com/problems/monthly-transactions-ii/) | [MySQL](./MySQL/monthly-transactions-ii.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1211 | [Queries Quality and Percentage](https://leetcode.com/problems/queries-quality-and-percentage/) | [MySQL](./MySQL/queries-quality-and-percentage.sql) | _O(n)_ | _O(n)_       | Easy           || |
1212 | [Team Scores in Football Tournament](https://leetcode.com/problems/team-scores-in-football-tournament/) | [MySQL](./MySQL/team-scores-in-football-tournament.sql) | _O(nlogn)_ | _O(n)_       | Medium           || |
1225 | [Report Contiguous Dates](https://leetcode.com/problems/report-contiguous-dates/) | [MySQL](./MySQL/report-contiguous-dates.sql) | _O(nlogn)_ | _O(n)_       | Hard           |🔒| |
1241 | [Number of Comments per Post](https://leetcode.com/problems/number-of-comments-per-post/) | [MySQL](./MySQL/number-of-comments-per-post.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1251 | [Average Selling Price](https://leetcode.com/problems/average-selling-price/) | [MySQL](./MySQL/average-selling-price.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1264 | [Page Recommendations](https://leetcode.com/problems/page-recommendations/) | [MySQL](./MySQL/page-recommendations.sql) | _O(m + n)_ | _O(m)_       | Medium           |🔒| |
1270 | [All People Report to the Given Manager](https://leetcode.com/problems/all-people-report-to-the-given-manager/) | [MySQL](./MySQL/all-people-report-to-the-given-manager.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1280 | [Students and Examinations](https://leetcode.com/problems/students-and-examinations/) | [MySQL](./MySQL/students-and-examinations.sql) | _O((m * n) * log(m * n))_ | _O(m * n)_       | Easy           |🔒| |
1285 | [Find the Start and End Number of Continuous Ranges](https://leetcode.com/problems/find-the-start-and-end-number-of-continuous-ranges/) | [MySQL](./MySQL/find-the-start-and-end-number-of-continuous-ranges.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1294 | [Weather Type in Each Country](https://leetcode.com/problems/weather-type-in-each-country/) | [MySQL](./MySQL/weather-type-in-each-country.sql) | _O(m + n)_ | _O(n)_       | Easy           |🔒| |
1303 | [Find the Team Size](https://leetcode.com/problems/find-the-team-size/) | [MySQL](./MySQL/find-the-team-size.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1308 | [Running Total for Different Genders](https://leetcode.com/problems/running-total-for-different-genders/) | [MySQL](./MySQL/running-total-for-different-genders.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1321 | [Restaurant Growth](https://leetcode.com/problems/restaurant-growth/) | [MySQL](./MySQL/restaurant-growth.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1322 | [Ads Performance](https://leetcode.com/problems/ads-performance/) | [MySQL](./MySQL/ads-performance.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒| |
1327 | [List the Products Ordered in a Period](https://leetcode.com/problems/list-the-products-ordered-in-a-period/) | [MySQL](./MySQL/list-the-products-ordered-in-a-period.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1336 | [Number of Transactions per Visit](https://leetcode.com/problems/number-of-transactions-per-visit/) | [MySQL](./MySQL/number-of-transactions-per-visit.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒| |
1341 | [Movie Rating](https://leetcode.com/problems/movie-rating/) | [MySQL](./MySQL/movie-rating.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1350 | [Students With Invalid Departments](https://leetcode.com/problems/students-with-invalid-departments/) | [MySQL](./MySQL/students-with-invalid-departments.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1355 | [Activity Participants](https://leetcode.com/problems/activity-participants/) | [MySQL](./MySQL/activity-participants.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1364 | [Number of Trusted Contacts of a Customer](https://leetcode.com/problems/number-of-trusted-contacts-of-a-customer/) | [MySQL](./MySQL/number-of-trusted-contacts-of-a-customer.sql) | _O(n + m + l + nlogn)_ | _O(n + m + l)_       | Medium           |🔒| |
1369 | [Get the Second Most Recent Activity](https://leetcode.com/problems/get-the-second-most-recent-activity/) | [MySQL](./MySQL/get-the-second-most-recent-activity.sql) | _O(nlogn)_ | _O(n)_       | Hard           |🔒| |
1378 | [Replace Employee ID With The Unique Identifier](https://leetcode.com/problems/replace-employee-id-with-the-unique-identifier/) | [MySQL](./MySQL/replace-employee-id-with-the-unique-identifier.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1384 | [Total Sales Amount by Year](https://leetcode.com/problems/total-sales-amount-by-year/) | [MySQL](./MySQL/total-sales-amount-by-year.sql) | _O(nlogn)_ | _O(n)_       | Hard           |🔒| |
1393 | [Capital Gain/Loss](https://leetcode.com/problems/capital-gainloss/) | [MySQL](./MySQL/capital-gainloss.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1398 | [Customers Who Bought Products A and B but Not C](https://leetcode.com/problems/customers-who-bought-products-a-and-b-but-not-c/) | [MySQL](./MySQL/customers-who-bought-products-a-and-b-but-not-c.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒| |
1407 | [Top Travellers](https://leetcode.com/problems/top-travellers/) | [MySQL](./MySQL/top-travellers.sql) | _O(m + nlogn)_ | _O(m + n)_       | Easy           |🔒| |
1412 | [Find the Quiet Students in All Exams](https://leetcode.com/problems/find-the-quiet-students-in-all-exams/) | [MySQL](./MySQL/find-the-quiet-students-in-all-exams.sql) | _O(m + nlogn)_ | _O(m + n)_       | Hard           |🔒| |
1421 | [NPV Queries](https://leetcode.com/problems/npv-queries/) | [MySQL](./MySQL/npv-queries.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1435 | [Create a Session Bar Chart](https://leetcode.com/problems/create-a-session-bar-chart/) | [MySQL](./MySQL/create-a-session-bar-chart.sql) | _O(n)_ | _O(1)_       | Easy           |🔒| |
1440 | [Evaluate Boolean Expression](https://leetcode.com/problems/evaluate-boolean-expression/) | [MySQL](./MySQL/evaluate-boolean-expression.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1445 | [Apples & Oranges](https://leetcode.com/problems/apples-oranges/) | [MySQL](./MySQL/apples-oranges.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1454 | [Active Users](https://leetcode.com/problems/active-users/) | [MySQL](./MySQL/active-users.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒| |
1459 | [Rectangles Area](https://leetcode.com/problems/rectangles-area/) | [MySQL](./MySQL/rectangles-area.sql) | _O(n^2)_ | _O(n^2)_       | Medium           |🔒| |
1468 | [Calculate Salaries](https://leetcode.com/problems/calculate-salaries/) | [MySQL](./MySQL/calculate-salaries.sql) | _O(m + n)_ | _O(m + n)_       | Easy           |🔒| |
1479 | [Sales by Day of the Week](https://leetcode.com/problems/sales-by-day-of-the-week/) | [MySQL](./MySQL/sales-by-day-of-the-week.sql) | _O(m + n)_ | _O(n)_       | Hard           |🔒| |
1484 | [Group Sold Products By The Date](https://leetcode.com/problems/group-sold-products-by-the-date/) | [MySQL](./MySQL/group-sold-products-by-the-date.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒| |
1495 | [Friendly Movies Streamed Last Month](https://leetcode.com/problems/friendly-movies-streamed-last-month/) | [MySQL](./MySQL/friendly-movies-streamed-last-month.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1501 | [Countries You Can Safely Invest In](https://leetcode.com/problems/countries-you-can-safely-invest-in/) | [MySQL](./MySQL/countries-you-can-safely-invest-in.sql) | _O(n)_ | _O(n)_       | Medium           |🔒| |
1511 | [Customer Order Frequency](https://leetcode.com/problems/customer-order-frequency/) | [MySQL](./MySQL/customer-order-frequency.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| |
1517 | [Find Users With Valid E-Mails](https://leetcode.com/problems/find-users-with-valid-e-mails/) | [MySQL](./MySQL/find-users-with-valid-e-mails.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| Regex |
1527 | [Patients With a Condition](https://leetcode.com/problems/patients-with-a-condition/) | [MySQL](./MySQL/patients-with-a-condition.sql) | _O(n)_ | _O(n)_       | Easy           |🔒| Regex |
1532 | [The Most Recent Three Orders](https://leetcode.com/problems/the-most-recent-three-orders/) | [MySQL](./MySQL/the-most-recent-three-orders.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1543 | [Fix Product Name Format](https://leetcode.com/problems/fix-product-name-format/) | [MySQL](./MySQL/fix-product-name-format.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1549 | [The Most Recent Orders for Each Product](https://leetcode.com/problems/the-most-recent-orders-for-each-product/) | [MySQL](./MySQL/the-most-recent-orders-for-each-product.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1555 | [Bank Account Summary](https://leetcode.com/problems/bank-account-summary/) | [MySQL](./MySQL/bank-account-summary.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒||
1565 | [Unique Orders and Customers Per Month](https://leetcode.com/problems/unique-orders-and-customers-per-month/) | [MySQL](./MySQL/unique-orders-and-customers-per-month.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1571 | [Warehouse Manager](https://leetcode.com/problems/warehouse-manager/) | [MySQL](./MySQL/warehouse-manager.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
1581 | [Customer Who Visited but Did Not Make Any Transactions](https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/) | [MySQL](./MySQL/customer-who-visited-but-did-not-make-any-transactions.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1587 | [Bank Account Summary II](https://leetcode.com/problems/bank-account-summary-ii/) | [MySQL](./MySQL/bank-account-summary-ii.sql) | _O(m + n)_ | _O(m + n)_       | Easy           |🔒||
1596 | [The Most Frequently Ordered Products for Each Customer](https://leetcode.com/problems/the-most-frequently-ordered-products-for-each-customer/) | [MySQL](./MySQL/the-most-frequently-ordered-products-for-each-customer.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
1607 | [Sellers With No Sales](https://leetcode.com/problems/sellers-with-no-sales/) | [MySQL](./MySQL/sellers-with-no-sales.sql) | _O(nlogm)_ | _O(n + m)_       | Medium           |🔒||
1613 | [Find the Missing IDs](https://leetcode.com/problems/find-the-missing-ids/) | [MySQL](./MySQL/find-the-missing-ids.sql) | _O(n^2)_ | _O(n)_       | Medium           |🔒||
1623 | [All Valid Triplets That Can Represent a Country](https://leetcode.com/problems/all-valid-triplets-that-can-represent-a-country/) | [MySQL](./MySQL/all-valid-triplets-that-can-represent-a-country.sql) | _O(n^3)_ | _O(n^3)_       | Easy           |🔒||
1633 | [Percentage of Users Attended a Contest](https://leetcode.com/problems/percentage-of-users-attended-a-contest/) | [MySQL](./MySQL/percentage-of-users-attended-a-contest.sql) | _O(m + nlogn)_ | _O(n)_       | Easy           |🔒||
1635 | [Hopper Company Queries I](https://leetcode.com/problems/hopper-company-queries-i/) | [MySQL](./MySQL/hopper-company-queries-i.sql) | _O(d + r + tlogt)_ | _O(d + r + t)_       | Hard           |🔒||
1645 | [Hopper Company Queries II](https://leetcode.com/problems/hopper-company-queries-ii/) | [MySQL](./MySQL/hopper-company-queries-ii.sql) | _O(d + r + tlogt)_ | _O(d + r + t)_       | Hard           |🔒||
1651 | [Hopper Company Queries III](https://leetcode.com/problems/hopper-company-queries-iii/) | [MySQL](./MySQL/hopper-company-queries-iii.sql) | _O(d + r + tlogt)_ | _O(d + r + t)_       | Hard           |🔒||
1661 | [Average Time of Process per Machine](https://leetcode.com/problems/average-time-of-process-per-machine/) | [MySQL](./MySQL/average-time-of-process-per-machine.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1667 | [Fix Names in a Table](https://leetcode.com/problems/fix-names-in-a-table/) | [MySQL](./MySQL/fix-names-in-a-table.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1677 | [Product's Worth Over Invoices](https://leetcode.com/problems/products-worth-over-invoices/) | [MySQL](./MySQL/products-worth-over-invoices.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1683 | [Invalid Tweets](https://leetcode.com/problems/invalid-tweets/) | [MySQL](./MySQL/invalid-tweets.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1693 | [Daily Leads and Partners](https://leetcode.com/problems/daily-leads-and-partners/) | [MySQL](./MySQL/daily-leads-and-partners.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1699 | [Number of Calls Between Two Persons](https://leetcode.com/problems/number-of-calls-between-two-persons/) | [MySQL](./MySQL/number-of-calls-between-two-persons.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
1709 | [Biggest Window Between Visits](https://leetcode.com/problems/biggest-window-between-visits/) | [MySQL](./MySQL/biggest-window-between-visits.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1715 | [Count Apples and Oranges](https://leetcode.com/problems/count-apples-and-oranges/) | [MySQL](./MySQL/count-apples-and-oranges.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
1729 | [Find Followers Count](https://leetcode.com/problems/find-followers-count/) | [MySQL](./MySQL/find-followers-count.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1731 | [The Number of Employees Which Report to Each Employee](https://leetcode.com/problems/the-number-of-employees-which-report-to-each-employee/) | [MySQL](./MySQL/the-number-of-employees-which-report-to-each-employee.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1741 | [Find Total Time Spent by Each Employee](https://leetcode.com/problems/find-total-time-spent-by-each-employee/) | [MySQL](./MySQL/find-total-time-spent-by-each-employee.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1747 | [Leetflex Banned Accounts](https://leetcode.com/problems/leetflex-banned-accounts/) | [MySQL](./MySQL/leetflex-banned-accounts.sql) | _O(n^2)_ | _O(n)_       | Medium           |🔒||
1757 | [Recyclable and Low Fat Products](https://leetcode.com/problems/recyclable-and-low-fat-products/) | [MySQL](./MySQL/recyclable-and-low-fat-products.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1767 | [Find the Subtasks That Did Not Execute](https://leetcode.com/problems/find-the-subtasks-that-did-not-execute/) | [MySQL](./MySQL/find-the-subtasks-that-did-not-execute.sql) | _O(n * c)_ | _O(n * c)_       | Hard           |🔒||
1777 | [Product's Price for Each Store](https://leetcode.com/problems/products-price-for-each-store/) | [MySQL](./MySQL/products-price-for-each-store.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1783 | [Grand Slam Titles](https://leetcode.com/problems/grand-slam-titles/) | [MySQL](./MySQL/grand-slam-titles.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
1789 | [Primary Department for Each Employee](https://leetcode.com/problems/primary-department-for-each-employee/) | [MySQL](./MySQL/primary-department-for-each-employee.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1795 | [Rearrange Products Table](https://leetcode.com/problems/rearrange-products-table/) | [MySQL](./MySQL/rearrange-products-table.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1809 | [Ad-Free Sessions](https://leetcode.com/problems/ad-free-sessions/) | [MySQL](./MySQL/ad-free-sessions.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1811 | [Find Interview Candidates](https://leetcode.com/problems/find-interview-candidates/) | [MySQL](./MySQL/find-interview-candidates.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1821 | [Find Customers With Positive Revenue this Year](https://leetcode.com/problems/find-customers-with-positive-revenue-this-year/) | [MySQL](./MySQL/find-customers-with-positive-revenue-this-year.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1831 | [Maximum Transaction Each Day](https://leetcode.com/problems/maximum-transaction-each-day/) | [MySQL](./MySQL/maximum-transaction-each-day.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1841 | [League Statistics](https://leetcode.com/problems/league-statistics/) | [MySQL](./MySQL/league-statistics.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1843 | [Suspicious Bank Accounts](https://leetcode.com/problems/suspicious-bank-accounts/) | [MySQL](./MySQL/suspicious-bank-accounts.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1853 | [Convert Date Format](https://leetcode.com/problems/convert-date-format/) | [MySQL](./MySQL/convert-date-format.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1867 | [Orders With Maximum Quantity Above Average](https://leetcode.com/problems/orders-with-maximum-quantity-above-average/) | [MySQL](./MySQL/orders-with-maximum-quantity-above-average.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1873 | [Calculate Special Bonus](https://leetcode.com/problems/calculate-special-bonus/) | [MySQL](./MySQL/calculate-special-bonus.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1875 | [Group Employees of the Same Salary](https://leetcode.com/problems/group-employees-of-the-same-salary/) | [MySQL](./MySQL/group-employees-of-the-same-salary.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
1890 | [The Latest Login in 2020](https://leetcode.com/problems/the-latest-login-in-2020/) | [MySQL](./MySQL/the-latest-login-in-2020.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
1892 | [Page Recommendations II](https://leetcode.com/problems/page-recommendations-ii/) | [MySQL](./MySQL/page-recommendations-ii.sql) | _O(n * m)_ | _O(n * m)_       | Hard           |🔒||
1907 | [Count Salary Categories](https://leetcode.com/problems/count-salary-categories/) | [MySQL](./MySQL/count-salary-categories.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
1917 | [Leetcodify Friends Recommendations](https://leetcode.com/problems/leetcodify-friends-recommendations/) | [MySQL](./MySQL/leetcodify-friends-recommendations.sql) | _O(n^2)_ | _O(n^2)_       | Hard           |🔒||
1919 | [Leetcodify Similar Friends](https://leetcode.com/problems/leetcodify-similar-friends/) | [MySQL](./MySQL/leetcodify-similar-friends.sql) | _O(n * l)_ | _O(n * l)_       | Hard           |🔒||
1934 | [Confirmation Rate](https://leetcode.com/problems/confirmation-rate/) | [MySQL](./MySQL/confirmation-rate.sql) | _O(n + m)_ | _O(n + m)_       | Medium           |🔒||
1939 | [Users That Actively Request Confirmation Messages](https://leetcode.com/problems/users-that-actively-request-confirmation-messages/) | [MySQL](./MySQL/users-that-actively-request-confirmation-messages.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1949 | [Strong Friendship](https://leetcode.com/problems/strong-friendship/) | [MySQL](./MySQL/strong-friendship.sql) | _O(n^3)_ | _O(n^2)_       | Medium           |🔒||
1951 | [All the Pairs With the Maximum Number of Common Followers](https://leetcode.com/problems/all-the-pairs-with-the-maximum-number-of-common-followers/) | [MySQL](./MySQL/all-the-pairs-with-the-maximum-number-of-common-followers.sql) | _O(n^3)_ | _O(n^2)_       | Medium           |🔒||
1965 | [Employees With Missing Information](https://leetcode.com/problems/employees-with-missing-information/) | [MySQL](./MySQL/employees-with-missing-information.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1972 | [First and Last Call On the Same Day](https://leetcode.com/problems/first-and-last-call-on-the-same-day/) | [MySQL](./MySQL/first-and-last-call-on-the-same-day.sql) | _O(n)_ | _O(n)_       | Hard           |🔒||
1978 | [Employees Whose Manager Left the Company](https://leetcode.com/problems/employees-whose-manager-left-the-company/) | [MySQL](./MySQL/employees-whose-manager-left-the-company.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
1988 | [Find Cutoff Score for Each School](https://leetcode.com/problems/find-cutoff-score-for-each-schooly/) | [MySQL](./MySQL/find-cutoff-score-for-each-school.sql) | _O(n * m)_ | _O(n * m)_       | Medium           |🔒||
1990 | [Count the Number of Experiments](https://leetcode.com/problems/count-the-number-of-experiments/) | [MySQL](./MySQL/count-the-number-of-experiments.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
2004 | [The Number of Seniors and Juniors to Join the Company](https://leetcode.com/problems/the-number-of-seniors-and-juniors-to-join-the-company/) | [MySQL](./MySQL/the-number-of-seniors-and-juniors-to-join-the-company.sql) | _O(nlogn)_ | _O(n)_       | Hard           |🔒||
2010 | [The Number of Seniors and Juniors to Join the Company II](https://leetcode.com/problems/the-number-of-seniors-and-juniors-to-join-the-company-ii/) | [MySQL](./MySQL/the-number-of-seniors-and-juniors-to-join-the-company.sql) | _O(nlogn)_ | _O(n)_       | Hard           |🔒||
2020 | [Number of Accounts That Did Not Stream](https://leetcode.com/problems/number-of-accounts-that-did-not-stream/) | [MySQL](./MySQL/number-of-accounts-that-did-not-stream.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒||
2026 | [Low-Quality Problems](https://leetcode.com/problems/low-quality-problems/) | [MySQL](./MySQL/low-quality-problems.sql) | _O(nlogn)_ | _O(n)_       | Easy           |🔒||
2041 | [Accepted Candidates From the Interviews](https://leetcode.com/problems/accepted-candidates-from-the-interviews/) | [MySQL](./MySQL/accepted-candidates-from-the-interviews.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒||
2051 | [The Category of Each Member in the Store](https://leetcode.com/problems/the-category-of-each-member-in-the-store/) | [MySQL](./MySQL/the-category-of-each-member-in-the-store.sql) | _O(m + n)_ | _O(m + n)_       | Medium           |🔒||
2066 | [Account Balance](https://leetcode.com/problems/account-balance/) | [MySQL](./MySQL/account-balance.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
2072 | [The Winner University](https://leetcode.com/problems/the-winner-university/) | [MySQL](./MySQL/the-winner-university.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
2082 | [The Number of Rich Customers](https://leetcode.com/problems/the-number-of-rich-customers/) | [MySQL](./MySQL/the-number-of-rich-customers.sql) | _O(n)_ | _O(n)_       | Easy           |🔒||
2084 | [Drop Type 1 Orders for Customers With Type 0 Orders](https://leetcode.com/problems/drop-type-1-orders-for-customers-with-type-0-orders/) | [MySQL](./MySQL/drop-type-1-orders-for-customers-with-type-0-orders.sql) | _O(nlogn)_ | _O(n)_       | Medium           |🔒||
2112 | [The Airport With the Most Traffic](https://leetcode.com/problems/the-airport-with-the-most-traffic/) | [MySQL](./MySQL/the-airport-with-the-most-traffic.sql) | _O(n)_ | _O(n)_       | Medium           |🔒||
2118 | [Build the Equation](https://leetcode.com/problems/build-the-equation/) | [MySQL](./MySQL/build-the-equation.sql) | _O(nlogn)_ | _O(n)_       | Hard           |🔒||
2142 | [The Number of Passengers in Each Bus I](https://leetcode.com/problems/the-number-of-passengers-in-each-bus-i/) | [MySQL](./MySQL/the-number-of-passengers-in-each-bus-i.sql) | _O(p * b + blogb)_ | _O(p * b)_       | Medium           |🔒||
2153 | [The Number of Passengers in Each Bus II](https://leetcode.com/problems/the-number-of-passengers-in-each-bus-ii/) | [MySQL](./MySQL/the-number-of-passengers-in-each-bus-ii.sql) | _O(p * b + blogb)_ | _O(p * b)_       | Hard           |🔒||

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## Shell Script
|  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
|-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|

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