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Group leetcode-algorithms Tele: https://t.me/+ST0unit9nTRkYjhl

Contribution guide

• Create a directory named <problem_id>.<Name-To-Directory> under Easy/, Medium/, or Hard/.
• Add a solution.md file inside that directory. Optional files: description.md, solution-go.md, solution-rust.md, solution-cpp.md.
• Example layout:

Easy/350.Intersection-of-Two-Arrays-II/
├── solution.md
└── description.md

• Markdown style guide: https://github.com/DavidAnson/markdownlint/blob/v0.35.0/doc/Rules.md
• When adding a new solution, add a row to the matching difficulty table below.

Solutions index

Total: 184 problems with at least one solution file.

Solution links use variant names when multiple approaches or languages exist (main = solution.md, others = solution-<variant>.md).

Easy (43)

Problem	LeetCode	Solution
100. Same Tree	Link	main
101. Symmetric Tree	Link	main
1021. Remove Outermost Parentheses	Link	main
1189. Maximum Number of Balloons	Link	main
136. Single Number	Link	main
145. Binary Tree Postorder Traversal	Link	main
155. Min Stack	Link	hashmap
219. Contains Duplicate II	Link	hashmap · slidingwindow
222. Count Complete Tree Nodes	Link	main
350. Intersection of Two Arrays II	Link	main
495. Teemo Attacking	Link	main
590. N-ary Tree Postorder Traversal	Link	main
594. Longest Harmonious Subsequence	Link	main
860. Lemonade Change	Link	main
884. Uncommon Words from Two Sentences	Link	main
1260. Shift 2D Grid	Link	main
1331. Rank Transform of an Array	Link	main
1399. Count Largest Group	Link	main
1455. Check If A Word Occurs As A Prefix Of Any Word In A Sentence	Link	main
1475. Final Prices With A Special Discount In A Shop	Link	main
1486. XOR Operation in an Array	Link	main
1518. Water Bottles	Link	main
1539. Kth Missing Positive Number	Link	main
1550. Three Consecutive Odds	Link	main
1598. Crawler Log Folder	Link	cpp
1636. Sort Array By Increasing Frequency	Link	main
1684. Count The Number Of Consistent Strings	Link	main
1945. Sum of Digits of String After Convert	Link	main
1967. Number of Strings That Appear as Substrings in Word	Link	main
1979. Find Greatest Common Divisor of Array	Link	main
2022. Convert 1D Array Into 2D Array	Link	main
2053. Kth Distinct String in an Array	Link	main
2191. Sort the Jumbled Numbers	Link	main
2418. Sort the People	Link	main
2558. Take Gifts From The Richest Pile	Link	main
2582. Passing The Pillow	Link	rust
2696. Minimum String Length After Removing Substrings	Link	main
3216. Lexicographically Smallest String After a Swap	Link	main
3314. Construct the Minimum Bitwise Array I	Link	main
3375. Minimum Operations to Make Array Values Equal to k	Link	main
3637. Trionic Array I	Link	main
3658. GCD of Odd and Even Sums	Link	main
3754. Concatenate Non-Zero Digits and Multiply by Sum I	Link	main

Medium (109)

Problem	LeetCode	Solution
33. Search in rotated sorted array	Link	main
40. Combination Sum II	Link	main
63. Unique Paths II	Link	main
81. Search In Rotated Sorted Array	Link	main
122. Best Time to Buy and Sell Stock II	Link	main
128. Longest Consecutive Sequence	Link	[main](Medium/128. Longest-Consecutive-Sequence/solution.md)
155. Min Stack	Link	main
179. Largest number	Link	main
208. Implement trie (prefix tree)	Link	main
209. Minimum Size Subarray Sum	Link	main
238. Product of Array Except Self	Link	main
241. Different Ways to Add Parentheses	Link	main
264. Ugly Number II	Link	main
300. Longest Increasing Subsequence	Link	[bottomup](Medium/300. Longest-Increasing-Subsequence/solution-bottomup.md) · [greedy-patience-sort](Medium/300. Longest-Increasing-Subsequence/solution-greedy-patience-sort.md) · [topdown](Medium/300. Longest-Increasing-Subsequence/solution-topdown.md)
307. Range sum query Mutable	Link	main
539. Minimum Time Difference	Link	main
567. Permutation in String	Link	main
624. Maximum Distance in Arrays	Link	main
654. Maximum Binary Tree	Link	main
725. Split Linked List in Parts	Link	main
729. My Calendar I	Link	main
739. Daily Temperatures	Link	main
763. Partition Labels	Link	main
790. Domino and Tromino Tiling	Link	main
807. Max Increase to Keep City Skyline	Link	main
826. Most Profit Assigning Work	Link	main
840. Magic Squares In Grid	Link	main
853. Car Fleet	Link	main
874. Walking Robot Simulation	Link	main
875. KoKo Eating Bananas	Link	main
885. Spiral Matrix III	Link	main
921. Minimum Add To Make Parentheses Valid	Link	main
947. Most Stones Removed with Same Row or Column	Link	main
959. Regions Cut By Slashes	Link	main
981. Time Based Key Value Store	Link	main
1014. Best Sightseeing Pair	Link	main
1038. Binary Search Tree to Greater Sum Tree	Link	main
1052. Grumpy Bookstore Owner	Link	main
1081. Smallest Subsequence of Distinct Characters	Link	main
1110. Delete Nodes And Return Forest	Link	main
1140. Stone Game II	Link	main
1190. Reverse Substrings Between Each Pair Of Parentheses	Link	main
1261. Find Elements in a Contaminated Binary Tree	Link	main
1288. Remove Covered Intervals	Link	main
1291. Sequential Digits	Link	main
1310. XOR Queries of a Subarray	Link	main
1371. Find the Longest Substring Containing Vowels in Even Counts	Link	main
1382. Balance A Binary Search Tree	Link	[main](Medium/1382. Balance-A-Binary-Search-Tree/solution.md)
1395. Count Number of Teams	Link	main
1438. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit	Link	main
1482. Minimum number of days to make m bouquets	Link	main
1497. Check If Array Pairs Are Divisible by k	Link	main
1530. Number of Good Leaf Nodes Pairs	Link	main
1552. Magnetic Force Between Two Balls	Link	main
1593. Split a String Into the Max Number of Unique Substrings	Link	main
1605. Find Valid Matrix Given Row and Column Sums	Link	[main](Medium/1605.Find-Valid -Matrix-Given-Row-and-Column-Sums/solution.md)
1653. Minimum Deletions to Make String Balanced	Link	main
1701. Average Waiting Time	Link	main
1717. Maximum Score From Removing Substrings	Link	main
1760. Minimum Limit Of Balls In A Bag	Link	main
1823. Find The Winner Of The Circular Game	Link	main
1833. Maximum Ice Cream Bars	Link	main
1846. Maximum Element After Decreasing and Rearranging	Link	main
1894. Find the Student that Will Replace the Chalk	Link	main
1905. Count Sub Islands	Link	cpp · go · java
1922. Count Good Numbers	Link	main
1942. The Number of the Smallest Unoccupied Chair	Link	main
1963. Minimum Number of Swaps to Make the String Balanced	Link	main
1975. Maxium Matrix Sum	Link	main
2028. Find Missing Observations	Link	main
2058. Find the Minimum and Maximum Number of Nodes Between Critical Points	Link	main
2070. Most Beautiful Item for Each Query	Link	main
2096. Step By Step Directions From A Binary Tree Node To Another	Link	go
2109. Adding Spaces To A String	Link	main
2161. Partition Array According to Given Pivot	Link	main
2181. Merge Nodes in Between Zeros	Link	main
2182. Construct string with repeat limit	Link	main
2192. All Ancestor of a Node in a Directed Acyclic Graph	Link	main
2196. Create Binary Tree From Descriptions	Link	cpp · go · java · rust
2226. Maximum candies allocate to K children	Link	[main](Medium/2226. Maximum-candies-allocate-to-K-children/solution.md)
2270. Number Of Ways To Split Array	Link	main
2285. Maximum Total Importance of Roads	Link	main
2326. Spiral Matrix IV	Link	main
2337. Move Pieces to Obtain a String	Link	main
2419. Longest Subarray With Maximum Bitwise AND	Link	main
2461. Maximum Sum of Distinct Subarrays With Length K	Link	main
2491. Divide Players Into Teams of Equal Skill	Link	main
2492. Minimum Score of a Path Between Two Cities	Link	main
2501. Longest Square Streak in an Array	Link	main
2583. Kth Largest Sum in a Binary Tree	Link	main
2601. Prime Subtraction Operation	Link	main
2685. Count the Number of Complete Components	Link	main
2707. Extra Characters In A String	Link	main
2779. Maximum Beauty Of An Array After Applying Operation	Link	main
2825. Make String a Subsequence Using Cyclic Increments	Link	main
2924. Find Champion II	Link	main
3016. Minimum Number of Pushes to Type Word II	Link	main
3020. Find the Maximum Number of Elements in Subset	Link	main
3043. Find the Length of the Longest Common Prefix	Link	main
3097. Shortest Subarray With OR at Least K II	Link	main
3217. Delete Nodes From Linked List Present in Array	Link	main
3218. Minimum Cost for Cutting Cake I	Link	main
3254. Find the Power of K Size Subarrays I	Link	main
3286. Find a Safe Walk Through a Grid	Link	main
3499. Maximize Active Section with Trade I	Link	main
3513. Number of Unique XOR Triplets I	Link	main
3532. Path Existence Queries in a Graph I	Link	main
3756. Concatenate Non-Zero Digits and Multiply by Sum II	Link	main
3867. Sum of GCD of Formed Pairs	Link	main

Hard (32)

Problem	LeetCode	Solution
11. Container With Most Water	Link	main
23. Merge k Sorted Lists	Link	main
37. Sudoku Solver	Link	[main](Hard/37. Sudoku Solver/solution.md)
41. First Missing Positive	Link	main
188. Best Time to Buy and Sell Stock IV	Link	main
212. Word Search II	Link	main
214. Shortest Palindrome	Link	main
239. Sliding Window Maximum	Link	main
295. Find Median from Data Stream	Link	main
502. IPO	Link	main
664. Strange Printer	Link	main
719. Find K th Smallest Pair Distance	Link	java · main
726. Number of Atoms	Link	go · main
773. Sliding Puzzle	Link	main
862. Shortest Subarray with Sum at Least K	Link	main
995. Minimum Number of K Consecutive Bit Flips	Link	main
1106. Parsing A Boolean Expression	Link	main
1301. Number of Paths with Max Score	Link	main
1579. Remove Max Number of Edges to Keep Graph Fully Traversable	Link	go · rust · main
2071. Maximum Number of Tasks You Can Assign	Link	main
2302. Count Subarrays With Score Less Than K	Link	main
2392. Build a Matrix With Conditions	Link	main
2416. Sum of Prefix Scores of Strings	Link	main
2503. Maximum Number of Points From Grid Queries	Link	main
2551. Put Marbles in Bags	Link	main
2751. Robot Collisions	Link	main
3219. Minimum Cost for Cutting Cake II	Link	main
3336. Find the Number of Subsequences With Equal GCD	Link	main
3363. Find the Maximum Number of Fruits Collected	Link	[main](Hard/3363. Find-the-Maximum-Number-of-Fruits-Collected/solution.md)
3534. Path Existence Queries in a Graph II	Link	main
3620. Network Recovery Pathways	Link	main
3739. Count Subarrays With Majority Element II	Link	main