{"id":19329893,"url":"https://github.com/zhongruoyu/leetcode","last_synced_at":"2026-03-08T05:31:55.986Z","repository":{"id":41801206,"uuid":"314496062","full_name":"ZhongRuoyu/LeetCode","owner":"ZhongRuoyu","description":"My LeetCode solutions.","archived":false,"fork":false,"pushed_at":"2023-02-05T08:40:11.000Z","size":785,"stargazers_count":4,"open_issues_count":0,"forks_count":0,"subscribers_count":2,"default_branch":"main","last_synced_at":"2025-04-22T22:41:47.720Z","etag":null,"topics":["leetcode","leetcode-solutions"],"latest_commit_sha":null,"homepage":"","language":"C++","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"mit","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/ZhongRuoyu.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null}},"created_at":"2020-11-20T08:47:00.000Z","updated_at":"2023-07-27T02:13:17.000Z","dependencies_parsed_at":"2023-02-17T19:16:06.017Z","dependency_job_id":null,"html_url":"https://github.com/ZhongRuoyu/LeetCode","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/ZhongRuoyu/LeetCode","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ZhongRuoyu%2FLeetCode","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ZhongRuoyu%2FLeetCode/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ZhongRuoyu%2FLeetCode/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ZhongRuoyu%2FLeetCode/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/ZhongRuoyu","download_url":"https://codeload.github.com/ZhongRuoyu/LeetCode/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/ZhongRuoyu%2FLeetCode/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":30246724,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-03-08T00:58:18.660Z","status":"online","status_checked_at":"2026-03-08T02:00:06.215Z","response_time":56,"last_error":null,"robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":true,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["leetcode","leetcode-solutions"],"created_at":"2024-11-10T02:31:46.938Z","updated_at":"2026-03-08T05:31:55.957Z","avatar_url":"https://github.com/ZhongRuoyu.png","language":"C++","funding_links":[],"categories":[],"sub_categories":[],"readme":"# My LeetCode Solutions\n\n## Table of Contents\n\n| Title                                                                                                                                                                         | Difficulty | Related Topics                                                                                            | Solution                                                                                                      |\n| ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------- | --------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------- |\n| [1. Two Sum](https://leetcode.com/problems/two-sum/)                                                                                                                          | Easy       | Array; Hash Table                                                                                         | [C++](problems/1-two-sum.cpp)                                                                                 |\n| [2. Add Two Numbers](https://leetcode.com/problems/add-two-numbers/)                                                                                                          | Medium     | Linked List; Math; Recursion                                                                              | [C](problems/2-add-two-numbers.c)                                                                             |\n| [3. Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters/)                                            | Medium     | Hash Table; String; Sliding Window                                                                        | [C++](problems/3-longest-substring-without-repeating-characters.cpp)                                          |\n| [5. Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring/)                                                                              | Medium     | String; Dynamic Programming                                                                               | [JavaScript](problems/5-longest-palindromic-substring.js)                                                     |\n| [7. Reverse Integer](https://leetcode.com/problems/reverse-integer/)                                                                                                          | Medium     | Math                                                                                                      | [C](problems/7-reverse-integer.c)                                                                             |\n| [8. String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi/)                                                                                          | Medium     | String                                                                                                    | [C](problems/8-string-to-integer-atoi.c)                                                                      |\n| [9. Palindrome Number](https://leetcode.com/problems/palindrome-number/)                                                                                                      | Easy       | Math                                                                                                      | [C](problems/9-palindrome-number.c)                                                                           |\n| [11. Container With Most Water](https://leetcode.com/problems/container-with-most-water/)                                                                                     | Medium     | Array; Two Pointers; Greedy                                                                               | [C++](problems/11-container-with-most-water.cpp)                                                              |\n| [12. Integer to Roman](https://leetcode.com/problems/integer-to-roman/)                                                                                                       | Medium     | Hash Table; Math; String                                                                                  | [C++](problems/12-integer-to-roman.cpp)                                                                       |\n| [13. Roman to Integer](https://leetcode.com/problems/roman-to-integer/)                                                                                                       | Easy       | Hash Table; Math; String                                                                                  | [C++](problems/13-roman-to-integer.cpp)                                                                       |\n| [14. Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/)                                                                                             | Easy       | String                                                                                                    | [C++](problems/14-longest-common-prefix.cpp)                                                                  |\n| [15. 3Sum](https://leetcode.com/problems/3sum/)                                                                                                                               | Medium     | Array; Two Pointers; Sorting                                                                              | [C++](problems/15-3sum.cpp)                                                                                   |\n| [16. 3Sum Closest](https://leetcode.com/problems/3sum-closest/)                                                                                                               | Medium     | Array; Two Pointers; Sorting                                                                              | [C++](problems/16-3sum-closest.cpp)                                                                           |\n| [17. Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/)                                                             | Medium     | Hash Table; Sorting; Backtracking                                                                         | [C++](problems/17-letter-combinations-of-a-phone-number.cpp)                                                  |\n| [18. 4Sum](https://leetcode.com/problems/4sum/)                                                                                                                               | Medium     | Array; Two Pointers; Sorting                                                                              | [C++](problems/18-4sum.cpp)                                                                                   |\n| [19. Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/)                                                                       | Medium     | Linked List; Two Pointers                                                                                 | [C++](problems/19-remove-nth-node-from-end-of-list.cpp)                                                       |\n| [20. Valid Parentheses](https://leetcode.com/problems/valid-parentheses/)                                                                                                     | Easy       | String; Stack                                                                                             | [C++](problems/20-valid-parentheses.cpp)                                                                      |\n| [21. Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/)                                                                                           | Easy       | Linked List; Recursion                                                                                    | [C](problems/21-merge-two-sorted-lists.c)                                                                     |\n| [22. Generate Parentheses](https://leetcode.com/problems/generate-parentheses/)                                                                                               | Medium     | String; Dynamic Programming; Backtracking                                                                 | [C++](problems/22-generate-parentheses.cpp)                                                                   |\n| [23. Merge k Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/)                                                                                               | Hard       | Linked List; Divide and Conquer; Heap (Priority Queue); Merge Sort                                        | [C++](problems/23-merge-k-sorted-lists.cpp)                                                                   |\n| [24. Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/)                                                                                                 | Medium     | Linked List; Recursion                                                                                    | [C](problems/24-swap-nodes-in-pairs.c)                                                                        |\n| [26. Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/)                                                                 | Easy       | Array; Two Pointers                                                                                       | [C++](problems/26-remove-duplicates-from-sorted-array.cpp)                                                    |\n| [27. Remove Element](https://leetcode.com/problems/remove-element/)                                                                                                           | Easy       | Array; Two Pointers                                                                                       | [C++](problems/27-remove-element.cpp)                                                                         |\n| [28. Implement strStr()](https://leetcode.com/problems/implement-strstr/)                                                                                                     | Easy       | Two Pointers; String; String Matching                                                                     | [C++](problems/28-implement-strstr.cpp)                                                                       |\n| [29. Divide Two Integers](https://leetcode.com/problems/divide-two-integers/)                                                                                                 | Medium     | Math; Bit Manipulation                                                                                    | [C++](problems/29-divide-two-integers.cpp)                                                                    |\n| [31. Next Permutation](https://leetcode.com/problems/next-permutation/)                                                                                                       | Medium     | Array; Two Pointers                                                                                       | [JavaScript](problems/31-next-permutation.js)                                                                 |\n| [32. Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/)                                                                                     | Hard       | String; Dynamic Programming; Stack                                                                        | [Rust](problems/32-longest-valid-parentheses.rs)                                                              |\n| [33. Search in Rotated Sorted Array](https://leetcode.com/problems/next-permutation/)                                                                                         | Medium     | Array; Binary Search                                                                                      | [JavaScript](problems/33-search-in-rotated-sorted-array.js)                                                   |\n| [34. Find First and Last Position of Element in Sorted Array](https://leetcode.com/problems/find-first-and-last-position-of-element-in-sorted-array/)                         | Medium     | Array; Binary Search                                                                                      | [JavaScript](problems/34-find-first-and-last-position-of-element-in-sorted-array.js)                          |\n| [35. Search Insert Position](https://leetcode.com/problems/search-insert-position/)                                                                                           | Easy       | Array; Binary Search                                                                                      | [C++](problems/35-search-insert-position.cpp)                                                                 |\n| [36. Valid Sudoku](https://leetcode.com/problems/valid-sudoku/)                                                                                                               | Medium     | Array; Hash Table; Matrix                                                                                 | [C++](problems/36-valid-sudoku.cpp)                                                                           |\n| [37. Sudoku Solver](https://leetcode.com/problems/sudoku-solver/)                                                                                                             | Hard       | Array; Backtracking; Matrix                                                                               | [C++](problems/37-sudoku-solver.cpp) / [JavaScript](problems/37-sudoku-solver.js)                             |\n| [38. Count and Say](https://leetcode.com/problems/count-and-say/)                                                                                                             | Medium     | String                                                                                                    | [C++](problems/38-count-and-say.cpp)                                                                          |\n| [41. First Missing Positive](https://leetcode.com/problems/first-missing-positive/)                                                                                           | Hard       | Array; Hash Table                                                                                         | [C++](problems/41-first-missing-positive.cpp)                                                                 |\n| [42. Trapping Rain Water](https://leetcode.com/problems/trapping-rain-water/)                                                                                                 | Hard       | Array; Two Pointers; Dynamic Programming; Stack; Monotonic Stack                                          | [C++](problems/42-trapping-rain-water.cpp)                                                                    |\n| [44. Wildcard Matching](https://leetcode.com/problems/wildcard-matching/)                                                                                                     | Hard       | String; Dynamic Programming; Greedy; Recursion                                                            | [Go](problems/44-wildcard-matching.go)                                                                        |\n| [46. Permutations](https://leetcode.com/problems/permutations/)                                                                                                               | Medium     | Array; Backtracking                                                                                       | [C++](problems/46-permutations.cpp)                                                                           |\n| [47. Permutations II](https://leetcode.com/problems/permutations-ii/)                                                                                                         | Medium     | Array; Backtracking                                                                                       | [C++](problems/47-permutations-ii.cpp)                                                                        |\n| [48. Rotate Image](https://leetcode.com/problems/rotate-image/)                                                                                                               | Medium     | Array; Math; Matrix                                                                                       | [C++](problems/48-rotate-image.cpp)                                                                           |\n| [49. Group Anagrams](https://leetcode.com/problems/group-anagrams/)                                                                                                           | Medium     | Hash Table; String; Sorting                                                                               | [C++](problems/49-group-anagrams.cpp)                                                                         |\n| [50. Pow(x, n)](https://leetcode.com/problems/powx-n/)                                                                                                                        | Medium     | Math; Recursion                                                                                           | [C](problems/50-powx-n.c)                                                                                     |\n| [51. N-Queens](https://leetcode.com/problems/n-queens/)                                                                                                                       | Hard       | Array; Backtracking                                                                                       | [C++](problems/51-n-queens.cpp)                                                                               |\n| [52. N-Queens II](https://leetcode.com/problems/n-queens-ii/)                                                                                                                 | Hard       | Backtracking                                                                                              | [C++](problems/52-n-queens-ii.cpp)                                                                            |\n| [53. Maximum Subarray](https://leetcode.com/problems/maximum-subarray/)                                                                                                       | Easy       | Array; Divide and Conquer; Dynamic Programming                                                            | [C++](problems/53-maximum-subarray.cpp)                                                                       |\n| [55. Jump Game](https://leetcode.com/problems/jump-game/)                                                                                                                     | Medium     | Array; Dynamic Programming; Greedy                                                                        | [JavaScript](problems/55-jump-game.js)                                                                        |\n| [56. Merge Intervals](https://leetcode.com/problems/merge-intervals/)                                                                                                         | Medium     | Array; Sorting                                                                                            | [C++](problems/56-merge-intervals.cpp)                                                                        |\n| [58. Length of Last Word](https://leetcode.com/problems/length-of-last-word/)                                                                                                 | Easy       | String                                                                                                    | [C++](problems/58-length-of-last-word.cpp)                                                                    |\n| [62. Unique Paths](https://leetcode.com/problems/unique-paths/)                                                                                                               | Medium     | Math; Dynamic Programming; Combinatorics                                                                  | [C++](problems/62-unique-paths.cpp)                                                                           |\n| [63. Unique Paths II](https://leetcode.com/problems/unique-paths-ii/)                                                                                                         | Medium     | Array; Dynamic Programming; Matrix                                                                        | [Rust](problems/63-unique-paths-ii.rs)                                                                        |\n| [65. Valid Number](https://leetcode.com/problems/valid-number/)                                                                                                               | Hard       | String                                                                                                    | [C++](problems/65-valid-number.cpp)                                                                           |\n| [66. Plus One](https://leetcode.com/problems/plus-one/)                                                                                                                       | Easy       | Array; Math                                                                                               | [C++](problems/66-plus-one.cpp)                                                                               |\n| [67. Add Binary](https://leetcode.com/problems/add-binary/)                                                                                                                   | Easy       | Math; String; Bit Manipulation; Simulation                                                                | [C](problems/67-add-binary.c)                                                                                 |\n| [68. Text Justification](https://leetcode.com/problems/text-justification/)                                                                                                   | Hard       | Array; String; Simulation                                                                                 | [Rust](problems/68-text-justification.rs)                                                                     |\n| [69. Sqrt(x)](https://leetcode.com/problems/sqrtx/)                                                                                                                           | Easy       | Math; Binary Search                                                                                       | [C](problems/69-sqrtx.c)                                                                                      |\n| [70. Climbing Stairs](https://leetcode.com/problems/climbing-stairs/)                                                                                                         | Easy       | Math; Dynamic Programming; Memorization                                                                   | [C++](problems/70-climbing-stairs.cpp)                                                                        |\n| [73. Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/)                                                                                                     | Medium     | Array; Hash Table; Matrix                                                                                 | [JavaScript](problems/73-set-matrix-zeroes.js)                                                                |\n| [74. Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix/)                                                                                                   | Medium     | Array; Binary Search; Matrix                                                                              | [C++](problems/74-search-a-2d-matrix.cpp)                                                                     |\n| [75. Sort Colors](https://leetcode.com/problems/sort-colors/)                                                                                                                 | Medium     | Array; Two Pointers; Sorting                                                                              | [JavaScript](problems/75-sort-colors.js)                                                                      |\n| [78. Subsets](https://leetcode.com/problems/subsets/)                                                                                                                         | Medium     | Array; Backtracking; Bit Manipulation                                                                     | [JavaScript](problems/78-subsets.js)                                                                          |\n| [79. Word Search](https://leetcode.com/problems/word-search/)                                                                                                                 | Medium     | Array; Backtracking; Matrix                                                                               | [C++](problems/79-word-search.cpp)                                                                            |\n| [82. Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/)                                                             | Medium     | Linked List; Two Pointers                                                                                 | [C++](problems/82-remove-duplicates-from-sorted-list-ii.cpp)                                                  |\n| [83. Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list/)                                                                   | Easy       | Linked List                                                                                               | [C++](problems/83-remove-duplicates-from-sorted-list.cpp)                                                     |\n| [86. Partition List](https://leetcode.com/problems/partition-list/)                                                                                                           | Medium     | Linked List; Two Pointers                                                                                 | [C++](problems/86-partition-list.cpp)                                                                         |\n| [88. Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array/)                                                                                                   | Easy       | Array; Two Pointers; Sorting                                                                              | [C](problems/88-merge-sorted-array.c) / [C++](problems/88-merge-sorted-array.cpp)                             |\n| [89. Gray Code](https://leetcode.com/problems/gray-code/)                                                                                                                     | Medium     | Math; Backtracking; Bit Manipulation                                                                      | [C++](problems/89-gray-code.cpp)                                                                              |\n| [91. Decode Ways](https://leetcode.com/problems/decode-ways/)                                                                                                                 | Medium     | String; Dynamic Programming                                                                               | [C++](problems/91-decode-ways.cpp)                                                                            |\n| [93. Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses/)                                                                                               | Medium     | String; Backtracking                                                                                      | [JavaScript](problems/93-restore-ip-addresses.js)                                                             |\n| [94. Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/)                                                                             | Easy       | Stack; Tree; Depth-First Search; Binary Tree                                                              | [JavaScript](problems/94-binary-tree-inorder-traversal.js)                                                    |\n| [100. Same Tree](https://leetcode.com/problems/same-tree/)                                                                                                                    | Easy       | Tree; Depth-First Search; Breadth-First Search; Binary Tree                                               | [C++](problems/100-same-tree.cpp)                                                                             |\n| [101. Symmetric Tree](https://leetcode.com/problems/symmetric-tree/)                                                                                                          | Easy       | Tree; Depth-First Search; Breadth-First Search; Binary Tree                                               | [C++](problems/101-symmetric-tree.cpp)                                                                        |\n| [104. Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/)                                                                              | Easy       | Tree; Depth-First Search; Breadth-First Search; Binary Tree                                               | [C++](problems/104-maximum-depth-of-binary-tree.cpp)                                                          |\n| [108. Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/)                                                  | Easy       | Array; Divide and Conquer; Tree; Binary Search Tree; Binary Tree                                          | [C++](problems/108-convert-sorted-array-to-binary-search-tree.cpp)                                            |\n| [115. Distinct Subsequences](https://leetcode.com/problems/distinct-subsequences/)                                                                                            | Hard       | String; Dynamic Programming                                                                               | [C++](problems/115-distinct-subsequences.cpp)                                                                 |\n| [118. Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/)                                                                                                     | Easy       | Array; Dynamic Programming                                                                                | [C++](problems/118-pascals-triangle.cpp)                                                                      |\n| [119. Pascal's Triangle II](https://leetcode.com/problems/pascals-triangle-ii/)                                                                                               | Easy       | Array; Dynamic Programming                                                                                | [Rust](problems/119-pascals-triangle-ii.rs)                                                                   |\n| [120. Triangle](https://leetcode.com/problems/triangle/)                                                                                                                      | Medium     | Array; Dynamic Programming                                                                                | [Rust](problems/120-triangle.rs)                                                                              |\n| [121. Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock)                                                                         | Easy       | Array; Dynamic Programming                                                                                | [C](problems/121-best-time-to-buy-and-sell-stock.c) / [C++](problems/121-best-time-to-buy-and-sell-stock.cpp) |\n| [125. Valid Palindrome](https://leetcode.com/problems/valid-palindrome/)                                                                                                      | Easy       | Two Pointers; String                                                                                      | [C](problems/125-valid-palindrome.c)                                                                          |\n| [128. Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/)                                                                              | Medium     | Array; Hash Table; Union Find                                                                             | [C++](problems/128-longest-consecutive-sequence.cpp)                                                          |\n| [136. Single Number](https://leetcode.com/problems/single-number/)                                                                                                            | Easy       | Array; Bit Manipulation                                                                                   | [C](problems/136-single-number.c)                                                                             |\n| [141. Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/)                                                                                                    | Easy       | Hash Table; Linked List; Two Pointers                                                                     | [C++](problems/141-linked-list-cycle.cpp)                                                                     |\n| [146. LRU Cache](https://leetcode.com/problems/lru-cache/)                                                                                                                    | Medium     | Hash Table; Linked List; Design; Doubly-Linked List                                                       | [C++](problems/146-lru-cache.cpp)                                                                             |\n| [150. Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/)                                                                      | Medium     | Array; Math; Stack                                                                                        | [C++](problems/150-evaluate-reverse-polish-notation.cpp)                                                      |\n| [155. Min Stack](https://leetcode.com/problems/min-stack/)                                                                                                                    | Easy       | Stack; Design                                                                                             | [C](problems/155-min-stack.c)                                                                                 |\n| [160. Intersection of Two Linked Lists](https://leetcode.com/problems/intersection-of-two-linked-lists/)                                                                      | Easy       | Hash Table; Linked List; Two Pointers                                                                     | [C++](problems/160-intersection-of-two-linked-lists.cpp)                                                      |\n| [167. Two Sum II - Input Array Is Sorted](https://leetcode.com/problems/two-sum-ii-input-array-is-sorted/)                                                                    | Easy       | Array; Two Pointers; Binary Search                                                                        | [C++](problems/167-two-sum-ii-input-array-is-sorted.cpp)                                                      |\n| [168. Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/)                                                                                      | Easy       | Math; String                                                                                              | [C++](problems/168-excel-sheet-column-title.cpp)                                                              |\n| [169. Majority Element](https://leetcode.com/problems/majority-element/)                                                                                                      | Easy       | Array; Hash Table; Divide and Conquer; Sorting; Counting                                                  | [C++](problems/169-majority-element.cpp)                                                                      |\n| [171. Excel Sheet Column Number](https://leetcode.com/problems/excel-sheet-column-number/)                                                                                    | Easy       | Math; String                                                                                              | [C](problems/171-excel-sheet-column-number.c)                                                                 |\n| [172. Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes/)                                                                                    | Medium     | Math                                                                                                      | [C](problems/172-factorial-trailing-zeroes.c)                                                                 |\n| [175. Combine Two Tables](https://leetcode.com/problems/combine-two-tables/)                                                                                                  | Easy       | Database                                                                                                  | [MySQL](problems/175-combine-two-tables.sql)                                                                  |\n| [176. Second Highest Salary](https://leetcode.com/problems/second-highest-salary/)                                                                                            | Medium     | Database                                                                                                  | [MySQL](problems/176-second-highest-salary.sql)                                                               |\n| [177. Nth Highest Salary](https://leetcode.com/problems/nth-highest-salary/)                                                                                                  | Medium     | Database                                                                                                  | [MySQL](problems/177-nth-highest-salary.sql)                                                                  |\n| [178. Rank Scores](https://leetcode.com/problems/rank-scores/)                                                                                                                | Medium     | Database                                                                                                  | [MySQL](problems/178-rank-scores.sql)                                                                         |\n| [179. Largest Number](https://leetcode.com/problems/largest-number/)                                                                                                          | Medium     | String; Greedy; Sorting                                                                                   | [Go](problems/179-largest-number.go)                                                                          |\n| [180. Consecutive Numbers](https://leetcode.com/problems/consecutive-numbers/)                                                                                                | Medium     | Database                                                                                                  | [MySQL](problems/180-consecutive-numbers.sql)                                                                 |\n| [181. Employees Earning More Than Their Managers](https://leetcode.com/problems/employees-earning-more-than-their-managers/)                                                  | Easy       | Database                                                                                                  | [MySQL](problems/181-employees-earning-more-than-their-managers.sql)                                          |\n| [182. Duplicate Emails](https://leetcode.com/problems/duplicate-emails/)                                                                                                      | Easy       | Database                                                                                                  | [MySQL](problems/182-duplicate-emails.sql)                                                                    |\n| [183. Customers Who Never Order](https://leetcode.com/problems/customers-who-never-order/)                                                                                    | Easy       | Database                                                                                                  | [MySQL](problems/183-customers-who-never-order.sql)                                                           |\n| [184. Department Highest Salary](https://leetcode.com/problems/department-highest-salary/)                                                                                    | Medium     | Database                                                                                                  | [MySQL](problems/184-department-highest-salary.sql)                                                           |\n| [185. Department Top Three Salaries](https://leetcode.com/problems/department-top-three-salaries/)                                                                            | Hard       | Database                                                                                                  | [MySQL](problems/185-department-top-three-salaries.sql)                                                       |\n| [189. Rotate Array](https://leetcode.com/problems/rotate-array/)                                                                                                              | Medium     | Array; Math; Two Pointers                                                                                 | [C++](problems/189-rotate-array.cpp)                                                                          |\n| [190. Reverse Bits](https://leetcode.com/problems/reverse-bits/)                                                                                                              | Easy       | Divide and Conquer; Bit Manipulation                                                                      | [C++](problems/190-reverse-bits.cpp)                                                                          |\n| [191. Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/)                                                                                                      | Easy       | Bit Manupulation                                                                                          | [C](problems/191-number-of-1-bits.c)                                                                          |\n| [192. Word Frequency](https://leetcode.com/problems/word-frequency/)                                                                                                          | Medium     | Shell                                                                                                     | [Bash](problems/192-word-frequency.sh)                                                                        |\n| [193. Valid Phone Numbers](https://leetcode.com/problems/valid-phone-numbers/)                                                                                                | Easy       | Shell                                                                                                     | [Bash](problems/193-valid-phone-numbers.sh)                                                                   |\n| [194. Transpose File](https://leetcode.com/problems/transpose-file/)                                                                                                          | Medium     | Shell                                                                                                     | [Bash](problems/194-transpose-file.sh)                                                                        |\n| [195. Tenth Line](https://leetcode.com/problems/tenth-line/)                                                                                                                  | Easy       | Shell                                                                                                     | [Bash](problems/195-tenth-line.sh)                                                                            |\n| [196. Delete Duplicate Emails](https://leetcode.com/problems/delete-duplicate-emails/)                                                                                        | Easy       | Database                                                                                                  | [MySQL](problems/196-delete-duplicate-emails.sql)                                                             |\n| [197. Rising Temperature](https://leetcode.com/problems/rising-temperature/)                                                                                                  | Easy       | Database                                                                                                  | [MySQL](problems/197-rising-temperature.sql)                                                                  |\n| [200. Number of Islands](https://leetcode.com/problems/number-of-islands/)                                                                                                    | Medium     | Array; Depth-First Search; Breadth-First Search; Union Find; Matrix                                       | [C++](problems/200-number-of-islands.cpp)                                                                     |\n| [202. Happy Number](https://leetcode.com/problems/happy-number/)                                                                                                              | Easy       | Hash Table; Math; Two Pointers                                                                            | [Go](problems/202-happy-number.go)                                                                            |\n| [203. Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/)                                                                                | Easy       | Linked List; Recursion                                                                                    | [C++](problems/203-remove-linked-list-elements.cpp)                                                           |\n| [204. Count Primes](https://leetcode.com/problems/count-primes/)                                                                                                              | Medium     | Array; Math; Enumeration; Number Theory                                                                   | [C](problems/204-count-primes.c)                                                                              |\n| [206. Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/)                                                                                                | Easy       | Linked List; Recursion                                                                                    | [C](problems/206-reverse-linked-list.c)                                                                       |\n| [208. Implement Trie (Prefix Tree)](https://leetcode.com/problems/implement-trie-prefix-tree/)                                                                                | Medium     | Hash Table; String; Design; Trie                                                                          | [Rust](problems/208-implement-trie-prefix-tree.rs)                                                            |\n| [211. Design Add and Search Words Data Structure](https://leetcode.com/problems/design-add-and-search-words-data-structure/)                                                  | Medium     | String; Depth-First Search; Design; Trie                                                                  | [C++](problems/211-design-add-and-search-words-data-structure.cpp)                                            |\n| [217. Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)                                                                                                  | Easy       | Array; Hash Table; Sorting                                                                                | [C++](problems/217-contains-duplicate.cpp)                                                                    |\n| [219. Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/)                                                                                            | Easy       | Array; Hash Table; Sliding Window                                                                         | [C++](problems/219-contains-duplicate-ii.cpp)                                                                 |\n| [220. Contains Duplicate III](https://leetcode.com/problems/contains-duplicate-iii/)                                                                                          | Medium     | Array; Sliding Window; Sorting; Bucket Sort; Ordered Set                                                  | [C++](problems/220-contains-duplicate-iii.cpp)                                                                |\n| [221. Maximal Square](https://leetcode.com/problems/maximal-square/)                                                                                                          | Medium     | Array; Dynamic Programming; Matrix                                                                        | [Rust](problems/221-maximal-square.rs)                                                                        |\n| [223. Rectangle Area](https://leetcode.com/problems/rectangle-area/)                                                                                                          | Medium     | Math; Geometry                                                                                            | [C++](problems/223-rectangle-area.cpp)                                                                        |\n| [226. Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/)                                                                                                  | Easy       | Tree; Depth-First Search; Breadth-First Search; Binary Tree                                               | [C](problems/226-invert-binary-tree.c)                                                                        |\n| [228. Summary Ranges](https://leetcode.com/problems/summary-ranges/)                                                                                                          | Easy       | Array                                                                                                     | [C++](problems/228-summary-ranges.cpp)                                                                        |\n| [231. Power of Two](https://leetcode.com/problems/power-of-two/)                                                                                                              | Easy       | Math; Bit Manipulation; Recursion                                                                         | [C](problems/231-power-of-two.c)                                                                              |\n| [237. Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list/)                                                                              | Easy       | Linked List                                                                                               | [C](problems/237-delete-node-in-a-linked-list.c)                                                              |\n| [238. Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/)                                                                              | Medium     | Array; Prefix Sum                                                                                         | [C++](problems/238-product-of-array-except-self.cpp)                                                          |\n| [239. Sliding Window Maximum](https://leetcode.com/problems/sliding-window-maximum/)                                                                                          | Hard       | Array; Queue; Sliding Window; Heap (Priority Queue); Monotonic Queue                                      | [Rust](problems/239-sliding-window-maximum.rs)                                                                |\n| [242. Valid Anagram](https://leetcode.com/problems/valid-anagram/)                                                                                                            | Easy       | Hash Table; String; Sorting                                                                               | [Rust](problems/242-valid-anagram.rs)                                                                         |\n| [258. Add Digits](https://leetcode.com/problems/add-digits/)                                                                                                                  | Easy       | Math; Simulation; Number Theory                                                                           | [C](problems/258-add-digits.c)                                                                                |\n| [262. Trips and Users](https://leetcode.com/problems/trips-and-users/)                                                                                                        | Hard       | Database                                                                                                  | [MySQL](problems/262-trips-and-users.sql)                                                                     |\n| [263. Ugly Number](https://leetcode.com/problems/ugly-number/)                                                                                                                | Easy       | Math                                                                                                      | [C](problems/263-ugly-number.c)                                                                               |\n| [268. Missing Number](https://leetcode.com/problems/missing-number/)                                                                                                          | Easy       | Array; Hash Table; Math; Bit Manipulation; Sorting                                                        | [C](problems/268-missing-number.c)                                                                            |\n| [278. First Bad Version](https://leetcode.com/problems/first-bad-version/)                                                                                                    | Easy       | Binary Search; Interactive                                                                                | [C++](problems/278-first-bad-version.cpp)                                                                     |\n| [283. Move Zeroes](https://leetcode.com/problems/move-zeroes/)                                                                                                                | Easy       | Array; Two Pointers                                                                                       | [C++](problems/283-move-zeroes.cpp)                                                                           |\n| [289. Game of Life](https://leetcode.com/problems/game-of-life/)                                                                                                              | Medium     | Array; Matrix; Simulation                                                                                 | [C++](problems/289-game-of-life.cpp)                                                                          |\n| [290. Word Pattern](https://leetcode.com/problems/word-pattern/)                                                                                                              | Easy       | Hash Table; String                                                                                        | [Ruby](problems/290-word-pattern.rb)                                                                          |\n| [292. Nim Game](https://leetcode.com/problems/nim-game/)                                                                                                                      | Easy       | Math; Brainteaser; Game Theory                                                                            | [C++](problems/292-nim-game.cpp)                                                                              |\n| [299. Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/)                                                                                                          | Medium     | Hash Table; String; Counting                                                                              | [Ruby](problems/299-bulls-and-cows.rb)                                                                        |\n| [303. Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/)                                                                                  | Easy       | Array; Design; Prefix Sum                                                                                 | [Go](problems/303-range-sum-query-immutable.go)                                                               |\n| [319. Bulb Switcher](https://leetcode.com/problems/bulb-switcher/)                                                                                                            | Easy       | Math; Brainteaser                                                                                         | [C++](problems/319-bulb-switcher.cpp)                                                                         |\n| [322. Coin Change](https://leetcode.com/problems/coin-change/)                                                                                                                | Medium     | Array; Dynamic Programming; Breadth-First Search                                                          | [Rust](problems/322-coin-change.rs)                                                                           |\n| [326. Power of Three](https://leetcode.com/problems/power-of-three/)                                                                                                          | Easy       | Math; Recursion                                                                                           | [C](problems/326-power-of-three.c)                                                                            |\n| [328. Odd Even Linked List](https://leetcode.com/problems/odd-even-linked-list/)                                                                                              | Medium     | Linked List                                                                                               | [C](problems/328-odd-even-linked-list.c)                                                                      |\n| [338. Counting Bits](https://leetcode.com/problems/counting-bits/)                                                                                                            | Easy       | Dynamic Programming; Bit Manipulation                                                                     | [C](problems/338-counting-bits.c)                                                                             |\n| [342. Power of Four](https://leetcode.com/problems/power-of-four/)                                                                                                            | Easy       | Math; Bit Manipulation; Recursion                                                                         | [C++](problems/342-power-of-four.cpp)                                                                         |\n| [344. Reverse String](https://leetcode.com/problems/reverse-string/)                                                                                                          | Easy       | Two Pointers; String; Recursion                                                                           | [C](problems/344-reverse-string.c) / [C++](problems/344-reverse-string.cpp)                                   |\n| [345. Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string/)                                                                                  | Easy       | Two Pointers; String                                                                                      | [Ruby](problems/345-reverse-vowels-of-a-string.rb)                                                            |\n| [347. Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/)                                                                                        | Medium     | Array; Hash Table; Divide and Conquer; Sorting; Heap (Priority Queue); Bucket Sort; Counting; Quickselect | [Rust](problems/347-top-k-frequent-elements.rs)                                                               |\n| [349. Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/)                                                                                  | Easy       | Array; Hash Table; Two Pointers; Binary Search; Sorting                                                   | [C++](problems/349-intersection-of-two-arrays.cpp)                                                            |\n| [350. Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/)                                                                            | Easy       | Array; Hash Table; Two Pointers; Binary Search; Sorting                                                   | [C++](problems/350-intersection-of-two-arrays-ii.cpp)                                                         |\n| [367. Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square/)                                                                                              | Easy       | Math; Binary Search                                                                                       | [C++](problems/367-valid-perfect-square.cpp)                                                                  |\n| [380. Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1/)                                                                                | Medium     | Array; Hash Table; Math; Design; Randomized                                                               | [Go](problems/380-insert-delete-getrandom-o1.go)                                                              |\n| [381. Insert Delete GetRandom O(1) - Duplicates allowed](https://leetcode.com/problems/insert-delete-getrandom-o1-duplicates-allowed/)                                        | Hard       | Array; Hash Table; Math; Design; Randomized                                                               | [Go](problems/381-insert-delete-getrandom-o1-duplicates-allowed.go)                                           |\n| [383. Ransom Note](https://leetcode.com/problems/ransom-note/)                                                                                                                | Easy       | Hash Table; String; Counting                                                                              | [C++](problems/383-ransom-note.cpp)                                                                           |\n| [387. First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string/)                                                                  | Easy       | Hash Table; String; Queue; Counting                                                                       | [C++](problems/387-first-unique-character-in-a-string.cpp)                                                    |\n| [389. Find the Difference](https://leetcode.com/problems/find-the-difference/)                                                                                                | Easy       | Hash Table; String; Bit Manipulation; Sorting                                                             | [C++](problems/389-find-the-difference.cpp)                                                                   |\n| [398. Random Pick Index](https://leetcode.com/problems/random-pick-index/)                                                                                                    | Medium     | Hash Table; Math; Reservoir Sampling; Randomized                                                          | [Rust](problems/398-random-pick-index.rs)                                                                     |\n| [401. Binary Watch](https://leetcode.com/problems/binary-watch/)                                                                                                              | Easy       | Backtracking; Bit Manipulation                                                                            | [C++](problems/401-binary-watch.cpp)                                                                          |\n| [404. Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/)                                                                                                  | Easy       | Tree; Depth-First Search; Breadth-First Search; Binary Tree                                               | [C++](problems/404-sum-of-left-leaves.cpp)                                                                    |\n| [405. Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal/)                                                                        | Easy       | Math; Bit Manipulation                                                                                    | [C++](problems/405-convert-a-number-to-hexadecimal.cpp)                                                       |\n| [406. Queue Reconstruction by Height](https://leetcode.com/problems/queue-reconstruction-by-height/)                                                                          | Medium     | Array; Greedy; Binary Indexed Tree; Segment Tree; Sorting                                                 | [Rust](problems/406-queue-reconstruction-by-height.rs)                                                        |\n| [412. Fizz Buzz](https://leetcode.com/problems/fizz-buzz/)                                                                                                                    | Easy       | Math; String; Simulation                                                                                  | [C++](problems/412-fizz-buzz.cpp)                                                                             |\n| [413. Arithmetic Slices](https://leetcode.com/problems/arithmetic-slices/)                                                                                                    | Medium     | Array; Dynamic Programming                                                                                | [Rust](problems/413-arithmetic-slices.rs)                                                                     |\n| [415. Add Strings](https://leetcode.com/problems/add-strings/)                                                                                                                | Easy       | Math; String; Simulation                                                                                  | [C](problems/415-add-strings.c)                                                                               |\n| [419. Battleships in a Board](https://leetcode.com/problems/battleships-in-a-board/)                                                                                          | Medium     | Array; Depth-First Search; Matrix                                                                         | [Rust](problems/419-battleships-in-a-board.rs)                                                                |\n| [430. Flatten a Multilevel Doubly Linked List](https://leetcode.com/problems/flatten-a-multilevel-doubly-linked-list/)                                                        | Medium     | Linked List; Depth-First Search; Doubly-Linked List                                                       | [C++](problems/430-flatten-a-multilevel-doubly-linked-list.cpp)                                               |\n| [434. Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string/)                                                                          | Easy       | String                                                                                                    | [Rust](problems/434-number-of-segments-in-a-string.rs)                                                        |\n| [438. Find All Anagrams in a String](https://leetcode.com/problems/find-all-anagrams-in-a-string/)                                                                            | Medium     | Hash Table; String; Sliding Window                                                                        | [JavaScript](problems/438-find-all-anagrams-in-a-string.js)                                                   |\n| [441. Arranging Coins](https://leetcode.com/problems/arranging-coins/)                                                                                                        | Easy       | Math; Binary Search                                                                                       | [C](problems/441-arranging-coins.c)                                                                           |\n| [442. Find All Duplicates in an Array](https://leetcode.com/problems/find-all-duplicates-in-an-array/)                                                                        | Medium     | Array; Hash Table                                                                                         | [Rust](problems/442-find-all-duplicates-in-an-array.rs)                                                       |\n| [448. Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/)                                                      | Easy       | Array; Hash Table                                                                                         | [Go](problems/448-find-all-numbers-disappeared-in-an-array.go)                                                |\n| [450. Delete Node in a BST](https://leetcode.com/problems/delete-node-in-a-bst/)                                                                                              | Medium     | Tree; Binary Search Tree; Binary Tree                                                                     | [C++](problems/450-delete-node-in-a-bst.cpp)                                                                  |\n| [455. Assign Cookies](https://leetcode.com/problems/assign-cookies/)                                                                                                          | Easy       | Array; Greedy; Sorting                                                                                    | [Go](problems/455-assign-cookies.go)                                                                          |\n| [458. Poor Pigs](https://leetcode.com/problems/poor-pigs/)                                                                                                                    | Hard       | Math; Dynamic Programming; Combinatorics                                                                  | [C++](problems/458-poor-pigs.cpp)                                                                             |\n| [461. Hamming Distance](https://leetcode.com/problems/hamming-distance/)                                                                                                      | Easy       | Bit Manipulation                                                                                          | [C++](problems/461-hamming-distance.cpp)                                                                      |\n| [463. Island Perimeter](https://leetcode.com/problems/island-perimeter/)                                                                                                      | Easy       | Array; Depth-First Search; Breadth-First Search; Matrix                                                   | [C++](problems/463-island-perimeter.cpp)                                                                      |\n| [468. Validate IP Address](https://leetcode.com/problems/validate-ip-address/)                                                                                                | Medium     | String                                                                                                    | [C++](problems/468-validate-ip-address.cpp)                                                                   |\n| [470. Implement Rand10() Using Rand7()](https://leetcode.com/problems/implement-rand10-using-rand7/)                                                                          | Medium     | Math; Rejection Sampling; Randomized; Probability and Statistics                                          | [JavaScript](problems/470-implement-rand10-using-rand7.js)                                                    |\n| [476. Number Complement](https://leetcode.com/problems/number-complement/)                                                                                                    | Easy       | Bit Manipulation                                                                                          | [C++](problems/476-number-complement.cpp)                                                                     |\n| [482. License Key Formatting](https://leetcode.com/problems/license-key-formatting/)                                                                                          | Easy       | String                                                                                                    | [Ruby](problems/482-license-key-formatting.rb)                                                                |\n| [485. Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones/)                                                                                              | Easy       | Array                                                                                                     | [Go](problems/485-max-consecutive-ones.go)                                                                    |\n| [492. Construct the Rectangle](https://leetcode.com/problems/construct-the-rectangle/)                                                                                        | Easy       | Math                                                                                                      | [Go](problems/492-construct-the-rectangle.go)                                                                 |\n| [495. Teemo Attacking](https://leetcode.com/problems/teemo-attacking/)                                                                                                        | Easy       | Array; Simulation                                                                                         | [C++](problems/495-teemo-attacking.cpp)                                                                       |\n| [500. Keyboard Row](https://leetcode.com/problems/keyboard-row/)                                                                                                              | Easy       | Array; Hash Table; String                                                                                 | [JavaScript](problems/500-keyboard-row.js)                                                                    |\n| [504. Base 7](https://leetcode.com/problems/base-7/)                                                                                                                          | Easy       | Math                                                                                                      | [Go](problems/504-base-7.go)                                                                                  |\n| [506. Relative Ranks](https://leetcode.com/problems/relative-ranks/)                                                                                                          | Easy       | Array; Sorting; Heap (Priority Queue)                                                                     | [Rust](problems/506-relative-ranks.rs)                                                                        |\n| [507. Perfect Number](https://leetcode.com/problems/perfect-number/)                                                                                                          | Easy       | Math                                                                                                      | [Go](problems/507-perfect-number.go)                                                                          |\n| [509. Fibonacci Number](https://leetcode.com/problems/fibonacci-number/)                                                                                                      | Easy       | Math; Dynamic Programming; Recursion; Memorization                                                        | [JavaScript](problems/509-fibonacci-number.js)                                                                |\n| [511. Game Play Analysis I](https://leetcode.com/problems/game-play-analysis-i/)                                                                                              | Easy       | Database                                                                                                  | [MySQL](problems/511-game-play-analysis-i.sql)                                                                |\n| [520. Detect Capital](https://leetcode.com/problems/detect-capital/)                                                                                                          | Easy       | String                                                                                                    | [Rust](problems/520-detect-capital.rs)                                                                        |\n| [521. Longest Uncommon Subsequence I](https://leetcode.com/problems/longest-uncommon-subsequence-i/)                                                                          | Easy       | String                                                                                                    | [C++](problems/521-longest-uncommon-subsequence-i.cpp)                                                        |\n| [535. Encode and Decode TinyURL](https://leetcode.com/problems/encode-and-decode-tinyurl/)                                                                                    | Medium     | Hash Table; String; Design; Hash Function                                                                 | [C++](problems/535-encode-and-decode-tinyurl.cpp)                                                             |\n| [537. Complex Number Multiplication](https://leetcode.com/problems/complex-number-multiplication/)                                                                            | Medium     | Math; String; Simulation                                                                                  | [C](problems/537-complex-number-multiplication.c)                                                             |\n| [541. Reverse String II](https://leetcode.com/problems/reverse-string-ii/)                                                                                                    | Easy       | Two Pointers; String                                                                                      | [Ruby](problems/541-reverse-string-ii.rb)                                                                     |\n| [543. Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree/)                                                                                        | Easy       | Tree; Depth-First Search; Binary Tree                                                                     | [JavaScript](problems/543-diameter-of-binary-tree.js)                                                         |\n| [554. Brick Wall](https://leetcode.com/problems/brick-wall/)                                                                                                                  | Medium     | Array; Hash Table                                                                                         | [C++](problems/554-brick-wall.cpp)                                                                            |\n| [557. Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii/)                                                                            | Easy       | Two Pointers; String                                                                                      | [C](problems/557-reverse-words-in-a-string-iii.c) / [C++](problems/557-reverse-words-in-a-string-iii.cpp)     |\n| [561. Array Partition](https://leetcode.com/problems/array-partition/)                                                                                                        | Easy       | Array; Greedy; Sorting; Counting Sort                                                                     | [Rust](problems/561-array-partition.rs)                                                                       |\n| [566. Reshape the Matrix](https://leetcode.com/problems/reshape-the-matrix/)                                                                                                  | Easy       | Array; Matrix; Simulation                                                                                 | [C++](problems/566-reshape-the-matrix.cpp)                                                                    |\n| [575. Distribute Candies](https://leetcode.com/problems/distribute-candies/)                                                                                                  | Easy       | Array; Hash Table                                                                                         | [Ruby](problems/575-distribute-candies.rb)                                                                    |\n| [584. Find Customer Referee](https://leetcode.com/problems/find-customer-referee/)                                                                                            | Easy       | Database                                                                                                  | [MySQL](problems/584-find-customer-referee.sql)                                                               |\n| [586. Customer Placing the Largest Number of Orders](https://leetcode.com/problems/customer-placing-the-largest-number-of-orders/)                                            | Easy       | Database                                                                                                  | [MySQL](problems/586-customer-placing-the-largest-number-of-orders.sql)                                       |\n| [594. Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence/)                                                                          | Easy       | Array; Hash Table; Sorting                                                                                | [Ruby](problems/594-longest-harmonious-subsequence.rb)                                                        |\n| [595. Big Countries](https://leetcode.com/problems/big-countries/)                                                                                                            | Easy       | Database                                                                                                  | [MySQL](problems/595-big-countries.sql)                                                                       |\n| [596. Classes More Than 5 Students](https://leetcode.com/problems/classes-more-than-5-students/)                                                                              | Easy       | Database                                                                                                  | [MySQL](problems/596-classes-more-than-5-students.sql)                                                        |\n| [598. Range Addition II](https://leetcode.com/problems/range-addition-ii/)                                                                                                    | Easy       | Array; Math                                                                                               | [Go](problems/598-range-addition-ii.go)                                                                       |\n| [599. Minimum Index Sum of Two Lists](https://leetcode.com/problems/minimum-index-sum-of-two-lists/)                                                                          | Easy       | Array; Hash Table; String                                                                                 | [Ruby](problems/599-minimum-index-sum-of-two-lists.rb)                                                        |\n| [601. Human Traffic of Stadium](https://leetcode.com/problems/human-traffic-of-stadium/)                                                                                      | Hard       | Database                                                                                                  | [MySQL](problems/601-human-traffic-of-stadium.sql)                                                            |\n| [605. Can Place Flowers](https://leetcode.com/problems/can-place-flowers/)                                                                                                    | Easy       | Array; Greedy                                                                                             | [C++](problems/605-can-place-flowers.cpp)                                                                     |\n| [607. Sales Person](https://leetcode.com/problems/sales-person/)                                                                                                              | Easy       | Database                                                                                                  | [MySQL](problems/607-sales-person.sql)                                                                        |\n| [608. Tree Node](https://leetcode.com/problems/tree-node/)                                                                                                                    | Medium     | Database                                                                                                  | [MySQL](problems/608-tree-node.sql)                                                                           |\n| [609. Find Duplicate File in System](https://leetcode.com/problems/find-duplicate-file-in-system/)                                                                            | Medium     | Array; Hash Table; String                                                                                 | [Rust](problems/609-find-duplicate-file-in-system.rs)                                                         |\n| [617. Merge Two Binary Trees](https://leetcode.com/problems/merge-two-binary-trees/)                                                                                          | Easy       | Tree; Depth-First Search; Breadth-First Search; Binary Tree                                               | [C++](problems/617-merge-two-binary-trees.cpp)                                                                |\n| [620. Not Boring Movies](https://leetcode.com/problems/not-boring-movies/)                                                                                                    | Easy       | Database                                                                                                  | [MySQL](problems/620-not-boring-movies.sql)                                                                   |\n| [626. Exchange Seats](https://leetcode.com/problems/exchange-seats/)                                                                                                          | Medium     | Database                                                                                                  | [MySQL](problems/626-exchange-seats.sql)                                                                      |\n| [627. Swap Salary](https://leetcode.com/problems/swap-salary/)                                                                                                                | Easy       | Database                                                                                                  | [MySQL](problems/627-swap-salary.sql)                                                                         |\n| [628. Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers/)                                                                      | Easy       | Array; Math; Sorting                                                                                      | [Go](problems/628-maximum-product-of-three-numbers.go)                                                        |\n| [643. Maximum Average Subarray I](https://leetcode.com/problems/maximum-average-subarray-i/)                                                                                  | Easy       | Array; Sliding Window                                                                                     | [Ruby](problems/643-maximum-average-subarray-i.rb)                                                            |\n| [645. Set Mismatch](https://leetcode.com/problems/set-mismatch/)                                                                                                              | Easy       | Array; Hash Table; Bit Manipulation; Sorting                                                              | [C++](problems/645-set-mismatch.cpp)                                                                          |\n| [647. Palindromic Substrings](https://leetcode.com/problems/palindromic-substrings/)                                                                                          | Medium     | String; Dynamic Programming                                                                               | [JavaScript](problems/647-palindromic-substrings.js)                                                          |\n| [657. Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin/)                                                                                          | Easy       | String; Simulation                                                                                        | [Rust](problems/657-robot-return-to-origin.rs)                                                                |\n| [665. Non-decreasing Array](https://leetcode.com/problems/non-decreasing-array/)                                                                                              | Medium     | Array                                                                                                     | [C++](problems/665-non-decreasing-array.cpp)                                                                  |\n| [680. Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii/)                                                                                                | Easy       | Two Pointers; String; Greedy                                                                              | [C](problems/680-valid-palindrome-ii.c)                                                                       |\n| [682. Baseball Game](https://leetcode.com/problems/baseball-game/)                                                                                                            | Easy       | Array; Stack; Simulation                                                                                  | [Rust](problems/682-baseball-game.rs)                                                                         |\n| [690. Employee Importance](https://leetcode.com/problems/employee-importance/)                                                                                                | Medium     | Hash Table; Depth-First Search; Breadth-First Search                                                      | [Ruby](problems/690-employee-importance.rb)                                                                   |\n| [693. Binary Number with Alternating Bits](https://leetcode.com/problems/binary-number-with-alternating-bits/)                                                                | Easy       | Bit Manipulation                                                                                          | [C++](problems/693-binary-number-with-alternating-bits.cpp)                                                   |\n| [695. Max Area of Island](https://leetcode.com/problems/max-area-of-island/)                                                                                                  | Medium     | Array; Depth-First Search; Breadth-First Search; Union Find; Matrix                                       | [Rust](problems/695-max-area-of-island.rs)                                                                    |\n| [697. Degree of an Array](https://leetcode.com/problems/degree-of-an-array/)                                                                                                  | Easy       | Array; Hash Table                                                                                         | [Ruby](problems/697-degree-of-an-array.rb)                                                                    |\n| [700. Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/)                                                                          | Easy       | Tree; Binary Search Tree; Binary Tree                                                                     | [C](problems/700-search-in-a-binary-search-tree.c)                                                            |\n| [703. Kth Largest Element in a Stream](https://leetcode.com/problems/kth-largest-element-in-a-stream/)                                                                        | Easy       | Tree; Design; Binary Search Tree; Heap (Priority Queue); Binary Tree; Data Stream                         | [Rust](problems/703-kth-largest-element-in-a-stream.rs)                                                       |\n| [704. Binary Search](https://leetcode.com/problems/binary-search/)                                                                                                            | Easy       | Array; Binary Search                                                                                      | [C](problems/704-binary-search.cpp)                                                                           |\n| [705. Design HashSet](https://leetcode.com/problems/design-hashset/)                                                                                                          | Easy       | Array; Hash Table; Linked List; Design; Hash Function                                                     | [Go](problems/705-design-hashset.go)                                                                          |\n| [706. Design HashMap](https://leetcode.com/problems/design-hashmap/)                                                                                                          | Easy       | Array; Hash Table; Linked List; Design; Hash Function                                                     | [C++](problems/706-design-hashmap.cpp)                                                                        |\n| [707. Design Linked List](https://leetcode.com/problems/design-linked-list/)                                                                                                  | Medium     | Linked List; Design                                                                                       | [C++](problems/707-design-linked-list.cpp)                                                                    |\n| [709. To Lower Case](https://leetcode.com/problems/to-lower-case/)                                                                                                            | Easy       | String                                                                                                    | [C](problems/709-to-lower-case.c)                                                                             |\n| [717. 1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters/)                                                                                  | Easy       | Array                                                                                                     | [C++](problems/717-1-bit-and-2-bit-characters.cpp)                                                            |\n| [724. Find Pivot Index](https://leetcode.com/problems/find-pivot-index/)                                                                                                      | Easy       | Array; Prefix Sum                                                                                         | [C++](problems/724-find-pivot-index.cpp)                                                                      |\n| [728. Self Dividing Numbers](https://leetcode.com/problems/self-dividing-numbers/)                                                                                            | Easy       | Math                                                                                                      | [JavaScript](problems/728-self-dividing-numbers.js)                                                           |\n| [739. Daily Temperatures](https://leetcode.com/problems/daily-temperatures/)                                                                                                  | Medium     | Array; Stack; Monotonic Stack                                                                             | [C++](problems/739-daily-temperatures.cpp) / [JavaScript](problems/739-daily-temperatures.js)                 |\n| [740. Delete and Earn](https://leetcode.com/problems/delete-and-earn/)                                                                                                        | Medium     | Array; Hash Table; Dynamic Programming                                                                    | [JavaScript](problems/740-delete-and-earn.js)                                                                 |\n| [744. Find Smallest Letter Greater Than Target](https://leetcode.com/problems/","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fzhongruoyu%2Fleetcode","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fzhongruoyu%2Fleetcode","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fzhongruoyu%2Fleetcode/lists"}