https://github.com/threeal/leetspace
A dedicated workspace and archive for my LeetCode submissions
https://github.com/threeal/leetspace
competitive-programming leetcode leetcode-cpp leetcode-solutions
Last synced: 6 months ago
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A dedicated workspace and archive for my LeetCode submissions
- Host: GitHub
- URL: https://github.com/threeal/leetspace
- Owner: threeal
- License: mit
- Created: 2023-09-13T10:41:38.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-12-11T09:34:37.000Z (6 months ago)
- Last Synced: 2025-12-11T18:14:30.677Z (6 months ago)
- Topics: competitive-programming, leetcode, leetcode-cpp, leetcode-solutions
- Language: C++
- Homepage: https://leetcode.com/threeal
- Size: 4.69 MB
- Stars: 1
- Watchers: 1
- Forks: 1
- Open Issues: 380
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# LeetSpace
LeetSpace serves as a dedicated workspace and archive for my [LeetCode](https://leetcode.com) submissions.
## Problems
| Problem | Difficulty | Solution |
|---|---|---|
| [1. Two Sum](https://leetcode.com/problems/two-sum) | Easy | [C](./old-problems/0001/c/solution.c) [C++](./old-problems/0001/solution.cpp) |
| [2. Add Two Numbers](https://leetcode.com/problems/add-two-numbers/) | Medium | [C++](./old-problems/0002/solution.cpp) |
| [3. Longest Substring Without Repeating Characters](https://leetcode.com/problems/longest-substring-without-repeating-characters) | Medium | [C](./old-problems/0003/c/solution.c) [C++](./old-problems/0003/solution.cpp) |
| [4. Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays) | Hard | [C](./old-problems/0004/c/solution.c) [C++](./old-problems/0004/solution.cpp) |
| [5. Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring) | Medium | [C](./old-problems/0005/c/solution.c) [C++](./old-problems/0005/solution.cpp) |
| [6. Zigzag Conversion](https://leetcode.com/problems/zigzag-conversion) | Medium | [C](./old-problems/0006/c/solution.c) [C++](./old-problems/0006/solution.cpp) |
| [7. Reverse Integer](https://leetcode.com/problems/reverse-integer/) | Medium | [C](./old-problems/0007/c/solution.c) [C++](./old-problems/0007/solution.cpp) |
| [8. String to Integer (atoi)](https://leetcode.com/problems/string-to-integer-atoi) | Medium | [C](./old-problems/0008/c/solution.c) [C++](./old-problems/0008/solution.cpp) |
| [9. Palindrome Number](https://leetcode.com/problems/palindrome-number) | Easy | [C](./old-problems/0009/c/solution.c) [C++](./old-problems/0009/solution.cpp) |
| [10. Regular Expression Matching](https://leetcode.com/problems/regular-expression-matching/) | Hard | [C](./old-problems/0010/c/solution.c) [C++](./old-problems/0010/solution.cpp) |
| [11. Container With Most Water](https://leetcode.com/problems/container-with-most-water) | Medium | [C++](./problems/0011/solution.cpp) |
| [12. Integer to Roman](https://leetcode.com/problems/integer-to-roman/) | Medium | [C](./old-problems/0012/c/solution.c) [C++](./old-problems/0012/solution.cpp) |
| [13. Roman to Integer](https://leetcode.com/problems/roman-to-integer/) | Easy | [C](./old-problems/0013/c/solution.c) [C++](./old-problems/0013/solution.cpp) |
| [14. Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix/) | Easy | [C](./old-problems/0014/c/solution.c) [C++](./old-problems/0014/solution.cpp) |
| [15. 3Sum](https://leetcode.com/problems/3sum) | Medium | [C++](./problems/0015/solution.cpp) |
| [16. 3Sum Closest](https://leetcode.com/problems/3sum-closest/) | Medium | [C](./old-problems/0016/c/solution.c) [C++](./old-problems/0016/solution.cpp) |
| [17. Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number) | Medium | [C++](./problems/0017/solution.cpp) |
| [18. 4Sum](https://leetcode.com/problems/4sum/) | Medium | [C](./old-problems/0018/c/solution.c) [C++](./old-problems/0018/solution.cpp) |
| [19. Remove Nth Node From End of List](https://leetcode.com/problems/remove-nth-node-from-end-of-list/) | Medium | [C++](./old-problems/0019/solution.cpp) |
| [20. Valid Parentheses](https://leetcode.com/problems/valid-parentheses/) | Easy | [C](./old-problems/0020/c/solution.c) [C++](./old-problems/0020/solution.cpp) |
| [21. Merge Two Sorted Lists](https://leetcode.com/problems/merge-two-sorted-lists/) | Easy | [C++](./old-problems/0021/solution.cpp) |
| [22. Generate Parentheses](https://leetcode.com/problems/generate-parentheses/) | Medium | [C](./old-problems/0022/c/solution.c) [C++](./old-problems/0022/solution.cpp) |
| [23. Merge k Sorted Lists](https://leetcode.com/problems/merge-k-sorted-lists/) | Hard | [C++](./old-problems/0023/solution.cpp) |
| [24. Swap Nodes in Pairs](https://leetcode.com/problems/swap-nodes-in-pairs/) | Medium | [C++](./old-problems/0024/solution.cpp) |
| [25. Reverse Nodes in k-Group](https://leetcode.com/problems/reverse-nodes-in-k-group/) | Hard | [C++](./old-problems/0025/solution.cpp) |
| [26. Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array) | Easy | [C++](./old-problems/0026/solution.cpp) |
| [27. Remove Element](https://leetcode.com/problems/remove-element) | Easy | [C++](./old-problems/0027/solution.cpp) |
| [28. Find the Index of the First Occurrence in a String](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string) | Easy | [C](./old-problems/0028/c/solution.c) [C++](./old-problems/0028/solution.cpp) |
| [29. Divide Two Integers](https://leetcode.com/problems/divide-two-integers/) | Medium | [C](./old-problems/0029/c/solution.c) [C++](./old-problems/0029/solution.cpp) |
| [30. Substring with Concatenation of All Words](https://leetcode.com/problems/substring-with-concatenation-of-all-words/) | Hard | [C++](./problems/0030/solution.cpp) |
| [31. Next Permutation](https://leetcode.com/problems/next-permutation/) | Medium | [C++](./old-problems/0031/solution.cpp) |
| [32. Longest Valid Parentheses](https://leetcode.com/problems/longest-valid-parentheses/) | Hard | [C](./old-problems/0032/c/solution.c) [C++](./old-problems/0032/solution.cpp) |
| [33. Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/) | Medium | [C++](./old-problems/0033/solution.cpp) |
| [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 | [C++](./problems/0034/solution.cpp) |
| [35. Search Insert Position](https://leetcode.com/problems/search-insert-position) | Easy | [C++](./problems/0035/solution.cpp) |
| [36. Valid Sudoku](https://leetcode.com/problems/valid-sudoku/) | Medium | [C](./old-problems/0036/c/solution.c) [C++](./old-problems/0036/solution.cpp) |
| [37. Sudoku Solver](https://leetcode.com/problems/sudoku-solver/) | Hard | [C++](./old-problems/0037/solution.cpp) |
| [38. Count and Say](https://leetcode.com/problems/count-and-say/) | Medium | [C](./old-problems/0038/c/solution.c) [C++](./old-problems/0038/solution.cpp) |
| [39. Combination Sum](https://leetcode.com/problems/combination-sum/) | Medium | [C++](./old-problems/0039/solution.cpp) |
| [40. Combination Sum II](https://leetcode.com/problems/combination-sum-ii/) | Medium | [C](./old-problems/0040/c/solution.c) [C++](./old-problems/0040/solution.cpp) |
| [41. First Missing Positive](https://leetcode.com/problems/first-missing-positive/) | Hard | [C](./old-problems/0041/c/solution.c) [C++](./old-problems/0041/solution.cpp) |
| [42. Trapping Rain Water](https://leetcode.com/problems/trapping-rain-water/) | Hard | [C](./old-problems/0042/c/solution.c) [C++](./old-problems/0042/solution.cpp) |
| [43. Multiply Strings](https://leetcode.com/problems/multiply-strings/) | Medium | [C](./old-problems/0043/c/solution.c) [C++](./old-problems/0043/solution.cpp) |
| [45. Jump Game II](https://leetcode.com/problems/jump-game-ii/) | Medium | [C](./old-problems/0045/c/solution.c) [C++](./old-problems/0045/solution.cpp) |
| [46. Permutations](https://leetcode.com/problems/permutations/) | Medium | [C](./old-problems/0046/c/solution.c) [C++](./old-problems/0046/solution.cpp) |
| [47. Permutations II](https://leetcode.com/problems/permutations-ii/) | Medium | [C](./old-problems/0047/c/solution.c) [C++](./old-problems/0047/solution.cpp) |
| [48. Rotate Image](https://leetcode.com/problems/rotate-image/) | Medium | [C++](./old-problems/0048/solution.cpp) |
| [49. Group Anagrams](https://leetcode.com/problems/group-anagrams/) | Medium | [C++](./problems/0049/solution.cpp) |
| [50. Pow(x, n)](https://leetcode.com/problems/powx-n/) | Medium | [C](./old-problems/0050/c/solution.c) [C++](./old-problems/0050/solution.cpp) |
| [51. N-Queens](https://leetcode.com/problems/n-queens/) | Hard | [C++](./problems/0051/solution.cpp) |
| [52. N-Queens II](https://leetcode.com/problems/n-queens-ii/) | Hard | [C](./old-problems/0052/c/solution.c) [C++](./old-problems/0052/solution.cpp) |
| [53. Maximum Subarray](https://leetcode.com/problems/maximum-subarray/) | Medium | [C](./old-problems/0053/c/solution.c) [C++](./old-problems/0053/solution.cpp) |
| [54. Spiral Matrix](https://leetcode.com/problems/spiral-matrix/) | Medium | [C](./old-problems/0054/c/solution.c) [C++](./old-problems/0054/solution.cpp) |
| [55. Jump Game](https://leetcode.com/problems/jump-game/) | Medium | [C](./old-problems/0055/c/solution.c) [C++](./old-problems/0055/solution.cpp) |
| [56. Merge Intervals](https://leetcode.com/problems/merge-intervals/) | Medium | [C](./old-problems/0056/c/solution.c) [C++](./old-problems/0056/solution.cpp) |
| [57. Insert Interval](https://leetcode.com/problems/insert-interval/) | Medium | [C](./old-problems/0057/c/solution.c) [C++](./old-problems/0057/solution.cpp) |
| [58. Length of Last Word](https://leetcode.com/problems/length-of-last-word) | Easy | [C](./old-problems/0058/c/solution.c) [C++](./old-problems/0058/solution.cpp) |
| [59. Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii/) | Medium | [C](./old-problems/0059/c/solution.c) [C++](./old-problems/0059/solution.cpp) |
| [60. Permutation Sequence](https://leetcode.com/problems/permutation-sequence/) | Hard | [C](./old-problems/0060/c/solution.c) [C++](./old-problems/0060/solution.cpp) |
| [61. Rotate List](https://leetcode.com/problems/rotate-list/) | Medium | [C++](./old-problems/0061/solution.cpp) |
| [62. Unique Paths](https://leetcode.com/problems/unique-paths/) | Medium | [C](./old-problems/0062/c/solution.c) [C++](./old-problems/0062/solution.cpp) |
| [63. Unique Paths II](https://leetcode.com/problems/unique-paths-ii/) | Medium | [C](./old-problems/0063/c/solution.c) [C++](./old-problems/0063/solution.cpp) |
| [64. Minimum Path Sum](https://leetcode.com/problems/minimum-path-sum/) | Medium | [C](./old-problems/0064/c/solution.c) [C++](./old-problems/0064/solution.cpp) |
| [65. Valid Number](https://leetcode.com/problems/valid-number/) | Hard | [C](./old-problems/0065/c/solution.c) [C++](./old-problems/0065/solution.cpp) |
| [66. Plus One](https://leetcode.com/problems/plus-one) | Easy | [C++](./problems/0066/solution.cpp) |
| [67. Add Binary](https://leetcode.com/problems/add-binary/) | Easy | [C](./old-problems/0067/c/solution.c) [C++](./old-problems/0067/solution.cpp) |
| [68. Text Justification](https://leetcode.com/problems/text-justification/) | Hard | [C](./old-problems/0068/c/solution.c) [C++](./old-problems/0068/solution.cpp) |
| [69. Sqrt(x)](https://leetcode.com/problems/sqrtx/) | Easy | [C](./old-problems/0069/c/solution.c) [C++](./old-problems/0069/solution.cpp) |
| [70. Climbing Stairs](https://leetcode.com/problems/climbing-stairs/) | Easy | [C](./old-problems/0070/c/solution.c) [C++](./old-problems/0070/solution.cpp) |
| [71. Simplify Path](https://leetcode.com/problems/simplify-path/) | Medium | [C](./old-problems/0071/c/solution.c) [C++](./old-problems/0071/solution.cpp) |
| [73. Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/) | Medium | [C++](./old-problems/0073/solution.cpp) |
| [74. Search a 2D Matrix](https://leetcode.com/problems/search-a-2d-matrix/) | Medium | [C](./old-problems/0074/c/solution.c) [C++](./old-problems/0074/solution.cpp) |
| [75. Sort Colors](https://leetcode.com/problems/sort-colors/) | Medium | [C++](./old-problems/0075/solution.cpp) |
| [77. Combinations](https://leetcode.com/problems/combinations/) | Medium | [C](./old-problems/0077/c/solution.c) [C++](./old-problems/0077/solution.cpp) |
| [78. Subsets](https://leetcode.com/problems/subsets/) | Medium | [C++](./old-problems/0078/solution.cpp) |
| [79. Word Search](https://leetcode.com/problems/word-search/) | Medium | [C](./old-problems/0079/c/solution.c) [C++](./old-problems/0079/solution.cpp) |
| [80. Remove Duplicates from Sorted Array II](https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/) | Medium | [C++](./old-problems/0080/solution.cpp) |
| [81. Search in Rotated Sorted Array II](https://leetcode.com/problems/search-in-rotated-sorted-array-ii/) | Medium | [C](./old-problems/0081/c/solution.c) [C++](./old-problems/0081/solution.cpp) |
| [82. Remove Duplicates from Sorted List II](https://leetcode.com/problems/remove-duplicates-from-sorted-list-ii/) | Medium | [C++](./old-problems/0082/solution.cpp) |
| [83. Remove Duplicates from Sorted List](https://leetcode.com/problems/remove-duplicates-from-sorted-list/) | Easy | [C++](./old-problems/0083/solution.cpp) |
| [84. Largest Rectangle in Histogram](https://leetcode.com/problems/largest-rectangle-in-histogram/) | Hard | [C](./old-problems/0084/c/solution.c) [C++](./old-problems/0084/solution.cpp) |
| [86. Partition List](https://leetcode.com/problems/partition-list/) | Medium | [C++](./old-problems/0086/solution.cpp) |
| [87. Scramble String](https://leetcode.com/problems/scramble-string/) | Hard | [C](./old-problems/0087/c/solution.c) [C++](./old-problems/0087/solution.cpp) |
| [88. Merge Sorted Array](https://leetcode.com/problems/merge-sorted-array/) | Easy | [C++](./old-problems/0088/solution.cpp) |
| [89. Gray Code](https://leetcode.com/problems/gray-code/) | Medium | [C](./old-problems/0089/c/solution.c) [C++](./old-problems/0089/solution.cpp) |
| [90. Subsets II](https://leetcode.com/problems/subsets-ii/) | Medium | [C](./old-problems/0090/c/solution.c) [C++](./old-problems/0090/solution.cpp) |
| [91. Decode Ways](https://leetcode.com/problems/decode-ways/) | Medium | [C](./old-problems/0091/c/solution.c) [C++](./old-problems/0091/solution.cpp) |
| [92. Reverse Linked List II](https://leetcode.com/problems/reverse-linked-list-ii/) | Medium | [C++](./old-problems/0092/solution.cpp) |
| [93. Restore IP Addresses](https://leetcode.com/problems/restore-ip-addresses/) | Medium | [C++](./old-problems/0093/solution.cpp) |
| [94. Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/) | Easy | [C++](./old-problems/0094/solution.cpp) |
| [97. Interleaving String](https://leetcode.com/problems/interleaving-string/) | Medium | [C](./old-problems/0097/c/solution.c) [C++](./old-problems/0097/solution.cpp) |
| [98. Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/) | Medium | [C++](./old-problems/0098/solution.cpp) |
| [100. Same Tree](https://leetcode.com/problems/same-tree/) | Easy | [C++](./old-problems/0100/solution.cpp) |
| [101. Symmetric Tree](https://leetcode.com/problems/symmetric-tree/) | Easy | [C++](./old-problems/0101/solution.cpp) |
| [104. Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/) | Easy | [C++](./old-problems/0104/solution.cpp) |
| [112. Path Sum](https://leetcode.com/problems/path-sum/) | Easy | [C++](./old-problems/0112/solution.cpp) |
| [113. Path Sum II](https://leetcode.com/problems/path-sum-ii/) | Medium | [C++](./old-problems/0113/solution.cpp) |
| [114. Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/) | Medium | [C++](./old-problems/0114/solution.cpp) |
| [115. Distinct Subsequences](https://leetcode.com/problems/distinct-subsequences/) | Hard | [C](./old-problems/0115/c/solution.c) [C++](./old-problems/0115/solution.cpp) |
| [118. Pascal's Triangle](https://leetcode.com/problems/pascals-triangle/) | Easy | [C](./old-problems/0118/c/solution.c) [C++](./old-problems/0118/solution.cpp) |
| [119. Pascal's Triangle II](pascals-triangle-ii) | Easy | [C](./old-problems/0119/c/solution.c) [C++](./old-problems/0119/solution.cpp) |
| [120. Triangle](https://leetcode.com/problems/triangle/) | Medium | [C](./old-problems/0120/c/solution.c) [C++](./old-problems/0120/solution.cpp) |
| [121. Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) | Easy | [C](./old-problems/0121/c/solution.c) [C++](./old-problems/0121/solution.cpp) |
| [122. Best Time to Buy and Sell Stock II](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-ii/) | Medium | [C](./old-problems/0122/c/solution.c) [C++](./old-problems/0122/solution.cpp) |
| [123. Best Time to Buy and Sell Stock III](https://leetcode.com/problems/best-time-to-buy-and-sell-stock-iii/) | Hard | [C](./old-problems/0123/c/solution.c) [C++](./old-problems/0123/solution.cpp) |
| [125. Valid Palindrome](https://leetcode.com/problems/valid-palindrome/description/) | Easy | [C](./old-problems/0125/c/solution.c) [C++](./old-problems/0125/solution.cpp) |
| [128. Longest Consecutive Sequence](https://leetcode.com/problems/longest-consecutive-sequence/) | Medium | [C](./old-problems/0128/c/solution.c) [C++](./old-problems/0128/solution.cpp) |
| [129. Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers) | Medium | [C++](./old-problems/0129/solution.cpp) |
| [130. Surrounded Regions](https://leetcode.com/problems/surrounded-regions/) | Medium | [C++](./old-problems/0130/solution.cpp) |
| [131. Palindrome Partitioning](https://leetcode.com/problems/palindrome-partitioning/) | Medium | [C](./old-problems/0131/c/solution.c) [C++](./old-problems/0131/solution.cpp) |
| [134. Gas Station](https://leetcode.com/problems/gas-station/) | Medium | [C](./old-problems/0134/c/solution.c) [C++](./old-problems/0134/solution.cpp) |
| [135. Candy](https://leetcode.com/problems/candy/) | Hard | [C](./old-problems/0135/c/solution.c) [C++](./old-problems/0135/solution.cpp) |
| [136. Single Number](https://leetcode.com/problems/single-number/) | Easy | [C](./old-problems/0136/solution.c) [C++](./old-problems/0136/solution.cpp) |
| [137. Single Number II](https://leetcode.com/problems/single-number-ii/) | Medium | [C](./old-problems/0137/c/solution.c) [C++](./old-problems/0137/solution.cpp) |
| [140. Word Break II](https://leetcode.com/problems/word-break-ii/) | Hard | [C++](./old-problems/0140/solution.cpp) |
| [141. Linked List Cycle](https://leetcode.com/problems/linked-list-cycle/) | Easy | [C++](./old-problems/0141/solution.cpp) |
| [142. Linked List Cycle II](https://leetcode.com/problems/linked-list-cycle-ii/) | Medium | [C++](./old-problems/0142/solution.cpp) |
| [143. Reorder List](https://leetcode.com/problems/reorder-list/) | Medium | [C++](./old-problems/0143/solution.cpp) |
| [144. Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/) | Easy | [C++](./old-problems/0144/solution.cpp) |
| [145. Binary Tree Postorder Traversal](https://leetcode.com/problems/binary-tree-postorder-traversal/) | Easy | [C++](./old-problems/0145/solution.cpp) |
| [148. Sort List](https://leetcode.com/problems/sort-list/) | Medium | [C++](./old-problems/0148/solution.cpp) |
| [149. Max Points on a Line](https://leetcode.com/problems/max-points-on-a-line/) | Hard | [C++](./old-problems/0149/solution.cpp) |
| [150. Evaluate Reverse Polish Notation](https://leetcode.com/problems/evaluate-reverse-polish-notation/) | Medium | [C](./old-problems/0150/c/solution.c) [C++](./old-problems/0150/solution.cpp) |
| [151. Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string/) | Medium | [C](./old-problems/0151/c/solution.c) [C++](./old-problems/0151/solution.cpp) |
| [152. Maximum Product Subarray](https://leetcode.com/problems/maximum-product-subarray/) | Medium | [C](./old-problems/0152/c/solution.c) [C++](./old-problems/0152/solution.cpp) |
| [153. Find Minimum in Rotated Sorted Array](https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/) | Medium | [C](./old-problems/0153/c/solution.c) [C++](./old-problems/0153/solution.cpp) |
| [164. Maximum Gap](https://leetcode.com/problems/maximum-gap/) | Medium | [C](./old-problems/0164/c/solution.c) [C++](./old-problems/0164/solution.cpp) |
| [165. Compare Version Numbers](https://leetcode.com/problems/compare-version-numbers/) | Medium | [C](./old-problems/0165/c/solution.c) [C++](./old-problems/0165/solution.cpp) |
| [166. Fraction to Recurring Decimal](https://leetcode.com/problems/fraction-to-recurring-decimal/) | Medium | [C++](./old-problems/0166/solution.cpp) |
| [168. Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/) | Easy | [C](./old-problems/0168/c/solution.c) [C++](./old-problems/0168/solution.cpp) |
| [169. Majority Element](https://leetcode.com/problems/majority-element/) | Easy | [C](./old-problems/0169/c/solution.c) [C++](./old-problems/0169/solution.cpp) |
| [173. Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/) | Medium | [C++](./old-problems/0173/solution.cpp) |
| [179. Largest Number](https://leetcode.com/problems/largest-number/) | Medium | [C](./old-problems/0179/c/solution.c) [C++](./old-problems/0179/solution.cpp) |
| [190. Reverse Bits](https://leetcode.com/problems/reverse-bits/) | Easy | [C](./old-problems/0190/c/solution.c) [C++](./old-problems/0190/solution.cpp) |
| [191. Number of 1 Bits](https://leetcode.com/problems/number-of-1-bits/) | Easy | [C](./old-problems/0191/c/solution.c) [C++](./old-problems/0191/solution.cpp) |
| [198. House Robber](https://leetcode.com/problems/house-robber/) | Medium | [C](./old-problems/0198/c/solution.c) [C++](./old-problems/0198/solution.cpp) |
| [200. Number of Islands](https://leetcode.com/problems/number-of-islands/) | Medium | [C](./old-problems/0200/c/solution.c) [C++](./old-problems/0200/solution.cpp) |
| [201. Bitwise AND of Numbers Range](https://leetcode.com/problems/bitwise-and-of-numbers-range/) | Medium | [C](./old-problems/0201/c/solution.c) [C++](./old-problems/0201/solution.cpp) |
| [202. Happy Number](https://leetcode.com/problems/happy-number/) | Easy | [C++](./old-problems/0202/solution.cpp) |
| [203. Remove Linked List Elements](https://leetcode.com/problems/remove-linked-list-elements/) | Easy | [C++](./old-problems/0203/solution.cpp) |
| [204. Count Primes](https://leetcode.com/problems/count-primes/) | Medium | [C](./old-problems/0204/c/solution.c) [C++](./old-problems/0204/solution.cpp) |
| [205. Isomorphic Strings](https://leetcode.com/problems/isomorphic-strings/) | Easy | [C](./old-problems/0205/c/solution.c) [C++](./old-problems/0205/solution.cpp) |
| [206. Reverse Linked List](https://leetcode.com/problems/reverse-linked-list/) | Easy | [C++](./old-problems/0206/solution.cpp) |
| [213. House Robber II](https://leetcode.com/problems/house-robber-ii/) | Medium | [C](./old-problems/0213/c/solution.c) [C++](./old-problems/0213/solution.cpp) |
| [214. Shortest Palindrome](https://leetcode.com/problems/shortest-palindrome/) | Hard | [C++](./problems/0214/solution.cpp) |
| [217. Contains Duplicate](https://leetcode.com/problems/contains-duplicate/) | Easy | [C](./old-problems/0217/c/solution.c) [C++](./old-problems/0217/solution.cpp) |
| [219. Contains Duplicate II](https://leetcode.com/problems/contains-duplicate-ii/) | Easy | [C++](./problems/0219/solution.cpp) |
| [224. Basic Calculator](https://leetcode.com/problems/basic-calculator/) | Hard | [C](./old-problems/0224/c/solution.c) [C++](./old-problems/0224/solution.cpp) |
| [226. Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/) | Easy | [C++](./old-problems/0226/solution.cpp) |
| [228. Summary Ranges](https://leetcode.com/problems/summary-ranges/) | Easy | [C](./old-problems/0228/c/solution.c) [C++](./old-problems/0228/solution.cpp) |
| [229. Majority Element II](https://leetcode.com/problems/majority-element-ii) | Medium | [C](./old-problems/0229/c/solution.c) [C++](./old-problems/0229/solution.cpp) |
| [230. Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst/) | Medium | [C++](./old-problems/0230/solution.cpp) |
| [231. Power of Two](https://leetcode.com/problems/power-of-two/) | Easy | [C](./old-problems/0231/c/solution.c) [C++](./old-problems/0231/solution.cpp) |
| [232. Implement Queue using Stacks](https://leetcode.com/problems/implement-queue-using-stacks/) | Easy | [C++](./old-problems/0232/solution.cpp) |
| [234. Palindrome Linked List](https://leetcode.com/problems/palindrome-linked-list/) | Easy | [C++](./old-problems/0234/solution.cpp) |
| [237. Delete Node in a Linked List](https://leetcode.com/problems/delete-node-in-a-linked-list/) | Medium | [C++](./old-problems/0237/solution.cpp) |
| [238. Product of Array Except Self](https://leetcode.com/problems/product-of-array-except-self/) | Medium | [C](./old-problems/0238/c/solution.c) [C++](./old-problems/0238/solution.cpp) |
| [241. Different Ways to Add Parentheses](https://leetcode.com/problems/different-ways-to-add-parentheses/) | Medium | [C++](./old-problems/0241/solution.cpp) |
| [242. Valid Anagram](https://leetcode.com/problems/valid-anagram/) | Easy | [C](./old-problems/0242/c/solution.c) [C++](./old-problems/0242/solution.cpp) |
| [258. Add Digits](https://leetcode.com/problems/add-digits/) | Easy | [C](./old-problems/0258/c/solution.c) [C++](./old-problems/0258/solution.cpp) |
| [260. Single Number III](https://leetcode.com/problems/single-number-iii/) | Medium | [C](./old-problems/0260/c/solution.c) [C++](./old-problems/0260/solution.cpp) |
| [263. Ugly Number](https://leetcode.com/problems/ugly-number/) | Easy | [C](./old-problems/0263/c/solution.c) [C++](./old-problems/0263/solution.cpp) |
| [264. Ugly Number II](https://leetcode.com/problems/ugly-number-ii/) | Medium | [C](./old-problems/0264/c/solution.c) [C++](./old-problems/0264/solution.cpp) |
| [268. Missing Number](https://leetcode.com/problems/missing-number/) | Easy | [C](./old-problems/0268/c/solution.c) [C++](./old-problems/0268/solution.cpp) |
| [273. Integer to English Words](https://leetcode.com/problems/integer-to-english-words/) | Hard | [C](./old-problems/0273/c/solution.c) [C++](./old-problems/0273/solution.cpp) |
| [274. H-Index](https://leetcode.com/problems/h-index/) | Medium | [C](./old-problems/0274/c/solution.c) [C++](./old-problems/0274/solution.cpp) |
| [275. H-Index II](https://leetcode.com/problems/h-index-ii/) | Medium | [C](./old-problems/0275/c/solution.c) [C++](./old-problems/0275/solution.cpp) |
| [278. First Bad Version](https://leetcode.com/problems/first-bad-version/) | Easy | [C++](./old-problems/0278/solution.cpp) |
| [279. Perfect Squares](https://leetcode.com/problems/perfect-squares/) | Medium | [C](./old-problems/0279/c/solution.c) [C++](./old-problems/0279/solution.cpp) |
| [283. Move Zeroes](https://leetcode.com/problems/move-zeroes/) | Easy | [C++](./old-problems/0283/solution.cpp) |
| [284. Peeking Iterator](https://leetcode.com/problems/peeking-iterator/) | Medium | [C++](./old-problems/0284/solution.cpp) |
| [287. Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/) | Medium | [C](./old-problems/0287/c/solution.c) [C++](./old-problems/0287/solution.cpp) |
| [289. Game of Life](https://leetcode.com/problems/game-of-life/) | Medium | [C++](./old-problems/0289/solution.cpp) |
| [290. Word Pattern](https://leetcode.com/problems/word-pattern/) | Easy | [C++](./old-problems/0290/solution.cpp) |
| [292. Nim Game](https://leetcode.com/problems/nim-game/) | Easy | [C](./old-problems/0292/c/solution.c) [C++](./old-problems/0292/solution.cpp) |
| [295. Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/) | Hard | [C++](./old-problems/0295/solution.cpp) |
| [297. Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/) | Hard | [C++](./old-problems/0297/solution.cpp) |
| [299. Bulls and Cows](https://leetcode.com/problems/bulls-and-cows/) | Medium | [C](./old-problems/0299/c/solution.c) [C++](./old-problems/0299/solution.cpp) |
| [300. Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | Medium | [C](./old-problems/0300/c/solution.c) [C++](./old-problems/0300/solution.cpp) |
| [303. Range Sum Query - Immutable](https://leetcode.com/problems/range-sum-query-immutable/) | Easy | [C++](./old-problems/0303/solution.cpp) |
| [310. Minimum Height Trees](https://leetcode.com/problems/minimum-height-trees/) | Medium | [C](./old-problems/0310/c/solution.c) [C++](./old-problems/0310/solution.cpp) |
| [313. Super Ugly Number](https://leetcode.com/problems/super-ugly-number/) | Medium | [C](./old-problems/0313/c/solution.c) [C++](./old-problems/0313/solution.cpp) |
| [316. Remove Duplicate Letters](https://leetcode.com/problems/remove-duplicate-letters) | Medium | [C++](./problems/0316/solution.cpp) |
| [319. Bulb Switcher](https://leetcode.com/problems/bulb-switcher/) | Medium | [C](./old-problems/0319/c/solution.c) [C++](./old-problems/0319/solution.cpp) |
| [322. Coin Change](https://leetcode.com/problems/coin-change/) | Medium | [C](./old-problems/0322/c/solution.c) [C++](./old-problems/0322/solution.cpp) |
| [326. Power of Three](https://leetcode.com/problems/power-of-three/) | Easy | [C](./old-problems/0326/c/solution.c) [C++](./old-problems/0326/solution.cpp) |
| [330. Patching Array](https://leetcode.com/problems/patching-array/) | Hard | [C](./old-problems/0330/c/solution.c) [C++](./old-problems/0330/solution.cpp) |
| [334. Increasing Triplet Subsequence](https://leetcode.com/problems/increasing-triplet-subsequence/) | Medium | [C](./old-problems/0334/c/solution.c) [C++](./old-problems/0334/solution.cpp) |
| [338. Counting Bits](https://leetcode.com/problems/counting-bits/) | Easy | [C](./old-problems/0338/c/solution.c) [C++](./old-problems/0338/solution.cpp) |
| [342. Power of Four](https://leetcode.com/problems/power-of-four) | Easy | [C](./old-problems/0342/c/solution.c) [C++](./old-problems/0342/solution.cpp) |
| [343. Integer Break](https://leetcode.com/problems/integer-break) | Medium | [C++](./problems/0343/solution.cpp) |
| [344. Reverse String](https://leetcode.com/problems/reverse-string/) | Easy | [C++](./old-problems/0344/solution.cpp) |
| [345. Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string/) | Easy | [C](./old-problems/0345/c/solution.c) [C++](./old-problems/0345/solution.cpp) |
| [347. Top K Frequent Elements](https://leetcode.com/problems/top-k-frequent-elements/) | Medium | [C++](./problems/0347/solution.cpp) |
| [349. Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/) | Easy | [C](./old-problems/0349/c/solution.c) [C++](./old-problems/0349/solution.cpp) |
| [350. Intersection of Two Arrays II](https://leetcode.com/problems/intersection-of-two-arrays-ii/) | Easy | [C](./old-problems/0350/c/solution.c) [C++](./old-problems/0350/solution.cpp) |
| [355. Design Twitter](https://leetcode.com/problems/design-twitter/) | Medium | [C++](./old-problems/0355/solution.cpp) |
| [357. Count Numbers with Unique Digits](https://leetcode.com/problems/count-numbers-with-unique-digits/) | Medium | [C](./old-problems/0357/c/solution.c) [C++](./old-problems/0357/solution.cpp) |
| [367. Valid Perfect Square](https://leetcode.com/problems/valid-perfect-square/) | Easy | [C](./old-problems/0367/c/solution.c) [C++](./old-problems/0367/solution.cpp) |
| [368. Largest Divisible Subset](https://leetcode.com/problems/largest-divisible-subset/) | Medium | [C](./old-problems/0368/c/solution.c) [C++](./old-problems/0368/solution.cpp) |
| [373. Find K Pairs with Smallest Sums](https://leetcode.com/problems/find-k-pairs-with-smallest-sums/) | Medium | [C](./old-problems/0373/c/solution.c) [C++](./old-problems/0373/solution.cpp) |
| [374. Guess Number Higher or Lower](https://leetcode.com/problems/guess-number-higher-or-lower/) | Medium | [C++](./old-problems/0374/solution.cpp) |
| [380. Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1/) | Medium | [C++](./old-problems/0380/solution.cpp) |
| [383. Ransom Note](https://leetcode.com/problems/ransom-note/) | Easy | [C](./old-problems/0383/c/solution.c) [C++](./old-problems/0383/solution.cpp) |
| [386. Lexicographical Numbers](https://leetcode.com/problems/lexicographical-numbers/) | Medium | [C](./old-problems/0386/c/solution.c) [C++](./old-problems/0386/solution.cpp) |
| [387. First Unique Character in a String](https://leetcode.com/problems/first-unique-character-in-a-string) | Easy | [C](./old-problems/0387/c/solution.c) [C++](./old-problems/0387/solution.cpp) |
| [389. Find the Difference](https://leetcode.com/problems/find-the-difference) | Easy | [C++](./problems/0389/solution.cpp) |
| [392. Is Subsequence](https://leetcode.com/problems/is-subsequence) | Easy | [C++](./problems/0392/solution.cpp) |
| [396. Rotate Function](https://leetcode.com/problems/rotate-function/) | Medium | [C](./old-problems/0396/c/solution.c) [C++](./old-problems/0396/solution.cpp) |
| [402. Remove K Digits](https://leetcode.com/problems/remove-k-digits/) | Medium | [C](./old-problems/0402/c/solution.c) [C++](./old-problems/0402/solution.cpp) |
| [404. Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/) | Easy | [C++](./old-problems/0404/solution.cpp) |
| [405. Convert a Number to Hexadecimal](https://leetcode.com/problems/convert-a-number-to-hexadecimal/) | Easy | [C](./old-problems/0405/c/solution.c) [C++](./old-problems/0405/solution.cpp) |
| [407. Trapping Rain Water II](https://leetcode.com/problems/trapping-rain-water-ii/) | Hard | [C](./old-problems/0407/c/solution.c) [C++](./old-problems/0407/solution.cpp) |
| [409. Longest Palindrome](https://leetcode.com/problems/longest-palindrome/) | Easy | [C](./old-problems/0409/c/solution.c) [C++](./old-problems/0409/solution.cpp) |
| [412. Fizz Buzz](https://leetcode.com/problems/fizz-buzz/) | Easy | [C](./old-problems/0412/c/solution.c) [C++](./old-problems/0412/solution.cpp) |
| [413. Arithmetic Slices](https://leetcode.com/problems/arithmetic-slices/) | Medium | [C](./old-problems/0413/c/solution.c) [C++](./old-problems/0413/solution.cpp) |
| [414. Third Maximum Number](https://leetcode.com/problems/third-maximum-number/) | Easy | [C](./old-problems/0414/c/solution.c) [C++](./old-problems/0414/solution.cpp) |
| [415. Add Strings](https://leetcode.com/problems/add-strings/) | Easy | [C](./old-problems/0415/c/solution.c) [C++](./old-problems/0415/solution.cpp) |
| [416. Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum/) | Medium | [C](./old-problems/0416/c/solution.c) [C++](./old-problems/0416/solution.cpp) |
| [417. Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/) | Medium | [C](./old-problems/0417/c/solution.c) [C++](./old-problems/0417/solution.cpp) |
| [419. Battleships in a Board](https://leetcode.com/problems/battleships-in-a-board/) | Medium | [C](./old-problems/0419/c/solution.c) [C++](./old-problems/0419/solution.cpp) |
| [432. All O`one Data Structure](https://leetcode.com/problems/all-oone-data-structure/) | Hard | [C++](./old-problems/0432/solution.cpp) |
| [434. Number of Segments in a String](https://leetcode.com/problems/number-of-segments-in-a-string) | Easy | [C](./old-problems/0434/c/solution.c) [C++](./old-problems/0434/solution.cpp) |
| [440. K-th Smallest in Lexicographical Order](https://leetcode.com/problems/k-th-smallest-in-lexicographical-order/) | Hard | [C](./old-problems/0440/c/solution.c) [C++](./old-problems/0440/solution.cpp) |
| [441. Arranging Coins](https://leetcode.com/problems/arranging-coins/) | Easy | [C](./old-problems/0441/c/solution.c) [C++](./old-problems/0441/solution.cpp) |
| [442. Find All Duplicates in an Array](https://leetcode.com/problems/find-all-duplicates-in-an-array/) | Medium | [C](./old-problems/0442/c/solution.c) [C++](./old-problems/0442/solution.cpp) |
| [446. Arithmetic Slices II - Subsequence](https://leetcode.com/problems/arithmetic-slices-ii-subsequence/) | Hard | [C++](./problems/0446/solution.cpp) |
| [448. Find All Numbers Disappeared in an Array](https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/) | Easy | [C](./old-problems/0448/c/solution.c) [C++](./old-problems/0448/solution.cpp) |
| [451. Sort Characters By Frequency](https://leetcode.com/problems/sort-characters-by-frequency/) | Medium | [C](./old-problems/0451/c/solution.c) [C++](./old-problems/0451/solution.cpp) |
| [452. Minimum Number of Arrows to Burst Balloons](https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/) | Medium | [C](./old-problems/0452/c/solution.c) [C++](./old-problems/0452/solution.cpp) |
| [454. 4Sum II](https://leetcode.com/problems/4sum-ii/) | Medium | [C++](./problems/0454/solution.cpp) |
| [455. Assign Cookies](https://leetcode.com/problems/assign-cookies) | Easy | [C](./old-problems/0455/c/solution.c) [C++](./old-problems/0455/solution.cpp) |
| [456. 132 Pattern](https://leetcode.com/problems/132-pattern) | Medium | [C](./old-problems/0456/c/solution.c) [C++](./old-problems/0456/solution.cpp) |
| [458. Poor Pigs](https://leetcode.com/problems/poor-pigs) | Hard | [C](./old-problems/0458/c/solution.c) [C++](./old-problems/0458/solution.cpp) |
| [459. Repeated Substring Pattern](https://leetcode.com/problems/repeated-substring-pattern/) | Easy | [C](./old-problems/0459/c/solution.c) [C++](./old-problems/0459/solution.cpp) |
| [461. Hamming Distance](https://leetcode.com/problems/hamming-distance/) | Easy | [C](./old-problems/0461/c/solution.c) [C++](./old-problems/0461/solution.cpp) |
| [462. Minimum Moves to Equal Array Elements II](https://leetcode.com/problems/minimum-moves-to-equal-array-elements-ii/) | Medium | [C](./old-problems/0462/c/solution.c) [C++](./old-problems/0462/solution.cpp) |
| [463. Island Perimeter](https://leetcode.com/problems/island-perimeter/) | Easy | [C](./old-problems/0463/c/solution.c) [C++](./old-problems/0463/solution.cpp) |
| [474. Ones and Zeroes](https://leetcode.com/problems/ones-and-zeroes/) | Medium | [C](./old-problems/0474/c/solution.c) [C++](./old-problems/0474/solution.cpp) |
| [476. Number Complement](https://leetcode.com/problems/number-complement/description/) | Easy | [C](./old-problems/0476/c/solution.c) [C++](./old-problems/0476/solution.cpp) |
| [485. Max Consecutive Ones](https://leetcode.com/problems/max-consecutive-ones/) | Easy | [C++](./old-problems/0485/solution.cpp) |
| [494. Target Sum](https://leetcode.com/problems/target-sum/) | Medium | [C](./old-problems/0494/c/solution.c) [C++](./old-problems/0494/solution.cpp) |
| [495. Teemo Attacking](https://leetcode.com/problems/teemo-attacking/) | Medium | [C](./old-problems/0495/c/solution.c) [C++](./old-problems/0495/solution.cpp) |
| [496. Next Greater Element I](https://leetcode.com/problems/next-greater-element-i/) | Easy | [C](./old-problems/0496/c/solution.c) [C++](./old-problems/0496/solution.cpp) |
| [498. Diagonal Traverse](https://leetcode.com/problems/diagonal-traverse/) | Medium | [C](./old-problems/0498/c/solution.c) [C++](./old-problems/0498/solution.cpp) |
| [500. Keyboard Row](https://leetcode.com/problems/keyboard-row/) | Easy | [C](./old-problems/0500/c/solution.c) [C++](./old-problems/0500/solution.cpp) |
| [502. IPO](https://leetcode.com/problems/ipo/) | Hard | [C](./old-problems/0502/c/solution.c) [C++](./old-problems/0502/solution.cpp) |
| [504. Base 7](https://leetcode.com/problems/base-7/) | Easy | [C](./old-problems/0504/c/solution.c) [C++](./old-problems/0504/solution.cpp) |
| [506. Relative Ranks](https://leetcode.com/problems/relative-ranks/) | Easy | [C](./old-problems/0506/c/solution.c) [C++](./old-problems/0506/solution.cpp) |
| [509. Fibonacci Number](https://leetcode.com/problems/fibonacci-number/) | Easy | [C](./old-problems/0509/c/solution.c) [C++](./old-problems/0509/solution.cpp) |
| [513. Find Bottom Left Tree Value](https://leetcode.com/problems/find-bottom-left-tree-value/) | Medium | [C++](./old-problems/0513/solution.cpp) |
| [514. Freedom Trail](https://leetcode.com/problems/freedom-trail/) | Hard | [C](./old-problems/0514/c/solution.c) [C++](./old-problems/0514/solution.cpp) |
| [515. Find Largest Value in Each Tree Row](https://leetcode.com/problems/find-largest-value-in-each-tree-row/) | Medium | [C++](./old-problems/0515/solution.cpp) |
| [520. Detect Capital](https://leetcode.com/problems/detect-capital/) | Easy | [C](./old-problems/0520/c/solution.c) [C++](./old-problems/0520/solution.cpp) |
| [523. Continuous Subarray Sum](https://leetcode.com/problems/continuous-subarray-sum/) | Medium | [C](./old-problems/0523/c/solution.c) [C++](./old-problems/0523/solution.cpp) |
| [525. Contiguous Array](https://leetcode.com/problems/contiguous-array/) | Medium | [C++](./problems/0525/solution.cpp) |
| [535. Encode and Decode TinyURL](https://leetcode.com/problems/encode-and-decode-tinyurl/) | Medium | [C++](./old-problems/0535/solution.cpp) |
| [539. Minimum Time Difference](https://leetcode.com/problems/minimum-time-difference/) | Medium | [C](./old-problems/0539/c/solution.c) [C++](./old-problems/0539/solution.cpp) |
| [541. Reverse String II](https://leetcode.com/problems/reverse-string-ii/) | Easy | [C](./old-problems/0541/c/solution.c) [C++](./old-problems/0541/solution.cpp) |
| [543. Diameter of Binary Tree](https://leetcode.com/problems/diameter-of-binary-tree/) | Easy | [C++](./old-problems/0543/solution.cpp) |
| [546. Remove Boxes](https://leetcode.com/problems/remove-boxes/) | Hard | [C](./old-problems/0546/c/solution.c) [C++](./old-problems/0546/solution.cpp) |
| [547. Number of Provinces](https://leetcode.com/problems/number-of-provinces/) | Medium | [C](./old-problems/0547/c/solution.c) [C++](./old-problems/0547/solution.cpp) |
| [552. Student Attendance Record II](https://leetcode.com/problems/student-attendance-record-ii/) | Hard | [C](./old-problems/0552/c/solution.c) [C++](./old-problems/0552/solution.cpp) |
| [557. Reverse Words in a String III](https://leetcode.com/problems/reverse-words-in-a-string-iii) | Easy | [C](./old-problems/0557/c/solution.c) [C++](./old-problems/0557/solution.cpp) |
| [561. Array Partition](https://leetcode.com/problems/array-partition/) | Easy | [C](./old-problems/0561/c/solution.c) [C++](./old-problems/0561/solution.cpp) |
| [566. Reshape the Matrix](https://leetcode.com/problems/reshape-the-matrix/) | Easy | [C](./old-problems/0566/c/solution.c) [C++](./old-problems/0566/solution.cpp) |
| [567. Permutation in String](https://leetcode.com/problems/permutation-in-string/) | Medium | [C](./old-problems/0567/c/solution.c) [C++](./old-problems/0567/solution.cpp) |
| [576. Out of Boundary Paths](https://leetcode.com/problems/out-of-boundary-paths/) | Medium | [C++](./problems/0576/solution.cpp) |
| [587. Erect the Fence](https://leetcode.com/problems/erect-the-fence/) | Hard | [C++](./old-problems/0587/solution.cpp) |
| [590. N-ary Tree Postorder Traversal](https://leetcode.com/problems/n-ary-tree-postorder-traversal/) | Easy | [C++](./old-problems/0590/solution.cpp) |
| [592. Fraction Addition and Subtraction](https://leetcode.com/problems/fraction-addition-and-subtraction/) | Medium | [C](./old-problems/0592/c/solution.c) [C++](./old-problems/0592/solution.cpp) |
| [594. Longest Harmonious Subsequence](https://leetcode.com/problems/longest-harmonious-subsequence/) | Easy | [C](./old-problems/0594/c/solution.c) [C++](./old-problems/0594/solution.cpp) |
| [598. Range Addition II](https://leetcode.com/problems/range-addition-ii/) | Easy | [C](./old-problems/0598/c/solution.c) [C++](./old-problems/0598/solution.cpp) |
| [605. Can Place Flowers](https://leetcode.com/problems/can-place-flowers/) | Easy | [C](./old-problems/0605/c/solution.c) [C++](./old-problems/0605/solution.cpp) |
| [606. Construct String from Binary Tree](https://leetcode.com/problems/construct-string-from-binary-tree/) | Easy | [C++](./old-problems/0606/solution.cpp) |
| [611. Valid Triangle Number](https://leetcode.com/problems/valid-triangle-number/) | Medium | [C](./old-problems/0611/c/solution.c) [C++](./old-problems/0611/solution.cpp) |
| [617. Merge Two Binary Trees](https://leetcode.com/problems/merge-two-binary-trees/) | Easy | [C++](./old-problems/0617/solution.cpp) |
| [621. Task Scheduler](https://leetcode.com/problems/task-scheduler/) | Medium | [C](./old-problems/0621/c/solution.c) [C++](./old-problems/0621/solution.cpp) |
| [623. Add One Row to Tree](https://leetcode.com/problems/add-one-row-to-tree/) | Medium | [C++](./old-problems/0623/solution.cpp) |
| [624. Maximum Distance in Arrays](https://leetcode.com/problems/maximum-distance-in-arrays/) | Medium | [C](./old-problems/0624/c/solution.c) [C++](./old-problems/0624/solution.cpp) |
| [628. Maximum Product of Three Numbers](https://leetcode.com/problems/maximum-product-of-three-numbers/) | Easy | [C](./old-problems/0628/c/solution.c) [C++](./old-problems/0628/solution.cpp) |
| [632. Smallest Range Covering Elements from K Lists](https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists/) | Hard | [C++](./old-problems/0632/solution.cpp) |
| [633. Sum of Square Numbers](https://leetcode.com/problems/sum-of-square-numbers/) | Medium | [C](./old-problems/0633/c/solution.c) [C++](./old-problems/0633/solution.cpp) |
| [637. Average of Levels in Binary Tree](https://leetcode.com/problems/average-of-levels-in-binary-tree/) | Easy | [C++](./old-problems/0637/solution.cpp) |
| [640. Solve the Equation](https://leetcode.com/problems/solve-the-equation/) | Medium | [C](./old-problems/0640/c/solution.c) [C++](./old-problems/0640/solution.cpp) |
| [641. Design Circular Deque](https://leetcode.com/problems/design-circular-deque/) | Medium | [C++](./old-problems/0641/solution.cpp) |
| [645. Set Mismatch](https://leetcode.com/problems/set-mismatch/) | Easy | [C](./old-problems/0645/c/solution.c) [C++](./old-problems/0645/solution.cpp) |
| [647. Palindromic Substrings](https://leetcode.com/problems/palindromic-substrings/) | Medium | [C](./old-problems/0647/c/solution.c) [C++](./old-problems/0647/solution.cpp) |
| [648. Replace Words](https://leetcode.com/problems/replace-words/) | Medium | [C++](./old-problems/0648/solution.cpp) |
| [650. 2 Keys Keyboard](https://leetcode.com/problems/2-keys-keyboard/) | Medium | [C](./old-problems/0650/c/solution.c) [C++](./old-problems/0650/solution.cpp) |
| [654. Maximum Binary Tree](https://leetcode.com/problems/maximum-binary-tree/) | Medium | [C++](./old-problems/0654/solution.cpp) |
| [655. Print Binary Tree](https://leetcode.com/problems/print-binary-tree/) | Medium | [C++](./old-problems/0655/solution.cpp) |
| [657. Robot Return to Origin](https://leetcode.com/problems/robot-return-to-origin/) | Easy | [C](./old-problems/0657/c/solution.c) [C++](./old-problems/0657/solution.cpp) |
| [661. Image Smoother](https://leetcode.com/problems/image-smoother/) | Easy | [C++](./problems/0661/solution.cpp) |
| [664. Strange Printer](https://leetcode.com/problems/strange-printer/) | Hard | [C](./old-problems/0664/c/solution.c) [C++](./old-problems/0664/solution.cpp) |
| [670. Maximum Swap](https://leetcode.com/problems/maximum-swap/) | Medium | [C](./old-problems/0670/c/solution.c) [C++](./old-problems/0670/solution.cpp) |
| [678. Valid Parenthesis String](https://leetcode.com/problems/valid-parenthesis-string/) | Medium | [C](./old-problems/0678/c/solution.c) [C++](./old-problems/0678/solution.cpp) |
| [679. 24 Game](https://leetcode.com/problems/24-game/) | Hard | [C](./old-problems/0679/c/solution.c) [C++](./old-problems/0679/solution.cpp) |
| [680. Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii/) | Easy | [C](./old-problems/0680/c/solution.c) [C++](./old-problems/0680/solution.cpp) |
| [682. Baseball Game](https://leetcode.com/problems/baseball-game/) | Easy | [C](./old-problems/0682/c/solution.c) [C++](./old-problems/0682/solution.cpp) |
| [684. Redundant Connection](https://leetcode.com/problems/redundant-connection/) | Medium | [C](./old-problems/0684/c/solution.c) [C++](./old-problems/0684/solution.cpp) |
| [689. Maximum Sum of 3 Non-Overlapping Subarrays](https://leetcode.com/problems/maximum-sum-of-3-non-overlapping-subarrays/) | Hard | [C](./old-problems/0689/c/solution.c) [C++](./old-problems/0689/solution.cpp) |
| [695. Max Area of Island](https://leetcode.com/problems/max-area-of-island/) | Medium | [C](./old-problems/0695/c/solution.c) [C++](./old-problems/0695/solution.cpp) |
| [696. Count Binary Substrings](https://leetcode.com/problems/count-binary-substrings/) | Easy | [C](./old-problems/0696/c/solution.c) [C++](./old-problems/0696/solution.cpp) |
| [700. Search in a Binary Search Tree](https://leetcode.com/problems/search-in-a-binary-search-tree/) | Easy | [C++](./old-problems/0700/solution.cpp) |
| [703. Kth Largest Element in a Stream](https://leetcode.com/problems/kth-largest-element-in-a-stream/) | Easy | [C++](./old-problems/0703/solution.cpp) |
| [709. To Lower Case](https://leetcode.com/problems/to-lower-case/) | Easy | [C](./old-problems/0709/c/solution.c) [C++](./old-problems/0709/solution.cpp) |
| [713. Subarray Product Less Than K](https://leetcode.com/problems/subarray-product-less-than-k/) | Medium | [C](./old-problems/0713/c/solution.c) [C++](./old-problems/0713/solution.cpp) |
| [717. 1-bit and 2-bit Characters](https://leetcode.com/problems/1-bit-and-2-bit-characters/) | Easy | [C](./old-problems/0717/c/solution.c) [C++](./old-problems/0717/solution.cpp) |
| [719. Find K-th Smallest Pair Distance](https://leetcode.com/problems/find-k-th-smallest-pair-distance/description/) | Hard | [C](./old-problems/0719/c/solution.c) [C++](./old-problems/0719/solution.cpp) |
| [725. Split Linked List in Parts](https://leetcode.com/problems/split-linked-list-in-parts/) | Medium | [C++](./old-problems/0725/solution.cpp) |
| [726. Number of Atoms](https://leetcode.com/problems/number-of-atoms/) | Hard | [C++](./problems/0726/solution.cpp) |
| [728. Self Dividing Numbers](https://leetcode.com/problems/self-dividing-numbers/) | Easy | [C](./old-problems/0728/c/solution.c) [C++](./old-problems/0728/solution.cpp) |
| [729. My Calendar I](https://leetcode.com/problems/my-calendar-i/) | Medium | [C++](./old-problems/0729/solution.cpp) |
| [731. My Calendar II](https://leetcode.com/problems/my-calendar-ii/) | Medium | [C++](./old-problems/0731/solution.cpp) |
| [739. Daily Temperatures](https://leetcode.com/problems/daily-temperatures/) | Medium | [C](./old-problems/0739/c/solution.c) [C++](./old-problems/0739/solution.cpp) |
| [746. Min Cost Climbing Stairs](https://leetcode.com/problems/min-cost-climbing-stairs) | Easy | [C++](./problems/0746/solution.cpp) |
| [752. Open the Lock](https://leetcode.com/problems/open-the-lock/) | Medium | [C](./old-problems/0752/c/solution.c) [C++](./old-problems/0752/solution.cpp) |
| [757. Set Intersection Size At Least Two](https://leetcode.com/problems/set-intersection-size-at-least-two/) | Hard | [C](./old-problems/0757/c/solution.c) [C++](./old-problems/0757/solution.cpp) |
| [763. Partition Labels](https://leetcode.com/problems/partition-labels/) | Medium | [C](./old-problems/0763/c/solution.c) [C++](./old-problems/0763/solution.cpp) |
| [769. Max Chunks To Make Sorted](https://leetcode.com/problems/max-chunks-to-make-sorted/) | Medium | [C++](./old-problems/0769/solution.cpp) |
| [771. Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/) | Easy | [C](./old-problems/0771/c/solution.c) [C++](./old-problems/0771/solution.cpp) |
| [773. Sliding Puzzle](https://leetcode.com/problems/sliding-puzzle/) | Hard | [C++](./problems/0773/solution.cpp) |
| [778. Swim in Rising Water](https://leetcode.com/problems/swim-in-rising-water/) | Hard | [C](./old-problems/0778/c/solution.c) [C++](./old-problems/0778/solution.cpp) |
| [779. K-th Symbol in Grammar](https://leetcode.com/problems/k-th-symbol-in-grammar) | Medium | [C](./old-problems/0779/c/solution.c) [C++](./old-problems/0779/solution.cpp) |
| [781. Rabbits in Forest](https://leetcode.com/problems/rabbits-in-forest/) | Medium | [C](./old-problems/0781/c/solution.c) [C++](./old-problems/0781/solution.cpp) |
| [784. Letter Case Permutation](https://leetcode.com/problems/letter-case-permutation/) | Medium | [C](./old-problems/0784/c/solution.c) [C++](./old-problems/0784/solution.cpp) |
| [786. K-th Smallest Prime Fraction](https://leetcode.com/problems/k-th-smallest-prime-fraction/) | Medium | [C](./old-problems/0786/c/solution.c) [C++](./old-problems/0786/solution.cpp) |
| [787. Cheapest Flights Within K Stops](https://leetcode.com/problems/cheapest-flights-within-k-stops/) | Medium | [C](./old-problems/0787/c/solution.c) [C++](./old-problems/0787/solution.cpp) |
| [790. Domino and Tromino Tiling](https://leetcode.com/problems/domino-and-tromino-tiling/) | Medium | [C](./old-problems/0790/c/solution.c) [C++](./old-problems/0790/solution.cpp) |
| [791. Custom Sort String](https://leetcode.com/problems/custom-sort-string/) | Medium | [C](./old-problems/0791/c/solution.c) [C++](./old-problems/0791/solution.cpp) |
| [796. Rotate String](https://leetcode.com/problems/rotate-string/) | Easy | [C](./old-problems/0796/c/solution.c) [C++](./old-problems/0796/solution.cpp) |
| [797. All Paths From Source to Target](https://leetcode.com/problems/all-paths-from-source-to-target/) | Medium | [C](./old-problems/0797/c/solution.c) [C++](./old-problems/0797/solution.cpp) |
| [802. Find Eventual Safe States](https://leetcode.com/problems/find-eventual-safe-states/) | Medium | [C](./old-problems/0802/c/solution.c) [C++](./old-problems/0802/solution.cpp) |
| [804. Unique Morse Code Words](https://leetcode.com/problems/unique-morse-code-words/) | Easy | [C++](./problems/0804/solution.cpp) |
| [807. Max Increase to Keep City Skyline](https://leetcode.com/problems/max-increase-to-keep-city-skyline/) | Medium | [C](./old-problems/0807/c/solution.c) [C++](./old-problems/0807/solution.cpp) |
| [811. Subdomain Visit Count](https://leetcode.com/problems/subdomain-visit-count/) | Medium | [C++](./old-problems/0811/solution.cpp) |
| [812. Largest Triangle Area](https://leetcode.com/problems/largest-triangle-area/) | Easy | [C](./old-problems/0812/c/solution.c) [C++](./old-problems/0812/solution.cpp) |
| [815. Bus Routes](https://leetcode.com/problems/bus-routes) | Hard | [C++](./problems/0815/solution.cpp) |
| [821. Shortest Distance to a Character](https://leetcode.com/problems/shortest-distance-to-a-character/) | Easy | [C++](./old-problems/0821/solution.cpp) |
| [823. Binary Trees With Factors](https://leetcode.com/problems/binary-trees-with-factors) | Medium | [C++](./problems/0823/solution.cpp) |
| [826. Most Profit Assigning Work](https://leetcode.com/problems/most-profit-assigning-work/) | Medium | [C](./old-problems/0826/c/solution.c) [C++](./old-problems/0826/solution.cpp) |
| [827. Making A Large Island](https://leetcode.com/problems/making-a-large-island/) | Hard | [C++](./old-problems/0827/solution.cpp) |
| [832. Flipping an Image](https://leetcode.com/problems/flipping-an-image/) | Easy | [C++](./old-problems/0832/solution.cpp) |
| [834. Sum of Distances in Tree](https://leetcode.com/problems/sum-of-distances-in-tree/) | Hard | [C](./old-problems/0834/c/solution.c) [C++](./old-problems/0834/solution.cpp) |
| [838. Push Dominoes](https://leetcode.com/problems/push-dominoes/) | Medium | [C](./old-problems/0838/c/solution.c) [C++](./old-problems/0838/solution.cpp) |
| [840. Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid/) | Medium | [C](./old-problems/0840/c/solution.c) [C++](./old-problems/0840/solution.cpp) |
| [844. Backspace String Compare](https://leetcode.com/problems/backspace-string-compare) | Easy | [C++](./problems/0844/solution.cpp) |
| [846. Hand of Straights](https://leetcode.com/problems/hand-of-straights/) | medium | [C](./old-problems/0846/c/solution.c) [C++](./old-problems/0846/solution.cpp) |
| [857. Minimum Cost to Hire K Workers](https://leetcode.com/problems/minimum-cost-to-hire-k-workers/) | Hard | [C++](./old-problems/0857/solution.cpp) |
| [859. Buddy Strings](https://leetcode.com/problems/buddy-strings/description/) | Easy | [C](./old-problems/0859/c/solution.c) [C++](./old-problems/0859/solution.cpp) |
| [860. Lemonade Change](https://leetcode.com/problems/lemonade-change/) | Easy | [C](./old-problems/0860/c/solution.c) [C++](./old-problems/0860/solution.cpp) |
| [861. Score After Flipping Matrix](https://leetcode.com/problems/score-after-flipping-matrix/) | Medium | [C](./old-problems/0861/c/solution.c) [C++](./old-problems/0861/solution.cpp) |
| [865. Smallest Subtree with all the Deepest Nodes](https://leetcode.com/problems/smallest-subtree-with-all-the-deepest-nodes/) | Medium | [C++](./old-problems/0865/solution.cpp) |
| [867. Transpose Matrix](https://leetcode.com/problems/transpose-matrix/) | Easy | [C](./old-problems/0867/c/solution.c) [C++](./old-problems/0867/solution.cpp) |
| [869. Reordered Power of 2](https://leetcode.com/problems/reordered-power-of-2/) | Medium | [C](./old-problems/0869/c/solution.c) [C++](./old-problems/0869/solution.cpp) |
| [872. Leaf-Similar Trees](https://leetcode.com/problems/leaf-similar-trees/) | Easy | [C++](./old-problems/0872/solution.cpp) |
| [873. Length of Longest Fibonacci Subsequence](https://leetcode.com/problems/length-of-longest-fibonacci-subsequence/) | Medium | [C](./old-problems/0873/c/solution.c) [C++](./old-problems/0873/solution.cpp) |
| [874. Walking Robot Simulation](https://leetcode.com/problems/walking-robot-simulation/) | Medium | [C++](./problems/0874/solution.cpp) |
| [875. Koko Eating Bananas](https://leetcode.com/problems/koko-eating-bananas/) | Medium | [C](./old-problems/0875/c/solution.c) [C++](./old-problems/0875/solution.cpp) |
| [876. Middle of the Linked List](https://leetcode.com/problems/middle-of-the-linked-list/) | Easy | [C++](./old-problems/0876/solution.cpp) |
| [877. Stone Game](https://leetcode.com/problems/stone-game/) | Medium | [C](./old-problems/0877/c/solution.c) [C++](./old-problems/0877/solution.cpp) |
| [880. Decoded String at Index](https://leetcode.com/problems/decoded-string-at-index) | Medium | [C++](./old-problems/0880/solution.cpp) |
| [881. Boats to Save People](https://leetcode.com/problems/boats-to-save-people/) | Medium | [C](./old-problems/0881/c/solution.c) [C++](./old-problems/0881/solution.cpp) |
| [883. Projection Area of 3D Shapes](https://leetcode.com/problems/projection-area-of-3d-shapes/) | Easy | [C](./old-problems/0883/c/solution.c) [C++](./old-problems/0883/solution.cpp) |
| [884. Uncommon Words from Two Sentences](https://leetcode.com/problems/uncommon-words-from-two-sentences/) | Easy | [C++](./old-problems/0884/solution.cpp) |
| [885. Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii/) | Medium | [C](./old-problems/0885/c/solution.c) [C++](./old-problems/0885/solution.cpp) |
| [888. Fair Candy Swap](https://leetcode.com/problems/fair-candy-swap/) | Easy | [C](./old-problems/0888/c/solution.c) [C++](./old-problems/0888/solution.cpp) |
| [889. Construct Binary Tree from Preorder and Postorder Traversal](https://leetcode.com/problems/construct-binary-tree-from-preorder-and-postorder-traversal/) | Medium | [C++](./old-problems/0889/solution.cpp) |
| [890. Find and Replace Pattern](https://leetcode.com/problems/find-and-replace-pattern/) | Medium | [C](./old-problems/0890/c/solution.c) [C++](./old-problems/0890/solution.cpp) |
| [892. Surface Area of 3D Shapes](https://leetcode.com/problems/surface-area-of-3d-shapes/) | Easy | [C++](./old-problems/0892/solution.cpp) |
| [893. Groups of Special-Equivalent Strings](https://leetcode.com/problems/groups-of-special-equivalent-strings/) | Medium | [C](./old-problems/0893/c/solution.c) [C++](./old-problems/0893/solution.cpp) |
| [894. All Possible Full Binary Trees](https://leetcode.com/problems/all-possible-full-binary-trees/) | Medium | [C++](./old-problems/0894/solution.cpp) |
| [897. Increasing Order Search Tree](https://leetcode.com/problems/increasing-order-search-tree/) | Easy | [C++](./old-problems/0897/solution.cpp) |
| [898. Bitwise ORs of Subarrays](https://leetcode.com/problems/bitwise-ors-of-subarrays/description/) | Medium | [C++](./old-problems/0898/solution.cpp) |
| [904. Fruit Into Baskets](https://leetcode.com/problems/fruit-into-baskets/) | Medium | [C](./old-problems/0904/c/solution.c) [C++](./old-problems/0904/solution.cpp) |
| [905. Sort Array By Parity](https://leetcode.com/problems/sort-array-by-parity) | Easy | [C++](./problems/0905/solution.cpp) |
| [907. Sum of Subarray Minimums](https://leetcode.com/problems/sum-of-subarray-minimums/) | Medium | [C](./old-problems/0907/c/solution.c) [C++](./old-problems/0907/solution.cpp) |
| [908. Smallest Range I](https://leetcode.com/problems/smallest-range-i/) | Easy | [C](./old-problems/0908/c/solution.c) [C++](./old-problems/0908/solution.cpp) |
| [909. Snakes and Ladders](https://leetcode.com/problems/snakes-and-ladders/) | Medium | [C](./old-problems/0909/c/solution.c) [C++](./old-problems/0909/solution.cpp) |
| [911. Online Election](https://leetcode.com/problems/online-election/) | Medium | [C++](./old-problems/0911/solution.cpp) |
| [912. Sort an Array](https://leetcode.com/problems/sort-an-array/) | Medium | [C](./old-problems/0912/c/solution.c) [C++](./old-problems/0912/solution.cpp) |
| [914. X of a Kind in a Deck of Cards](https://leetcode.com/problems/x-of-a-kind-in-a-deck-of-cards/) | Easy | [C](./old-problems/0914/c/solution.c) [C++](./old-problems/0914/solution.cpp) |
| [916. Word Subsets](https://leetcode.com/problems/word-subsets/) | Medium | [C](./old-problems/0916/c/solution.c) [C++](./old-problems/0916/solution.cpp) |
| [921. Minimum Add to Make Parentheses Valid](https://leetcode.com/problems/minimum-add-to-make-parentheses-valid/) | Medium | [C](./old-problems/0921/c/solution.c) [C++](./old-problems/0921/solution.cpp) |
| [925. Long Pressed Name](https://leetcode.com/problems/long-pressed-name/) | Easy | [C](./old-problems/0925/c/solution.c) [C++](./old-problems/0925/solution.cpp) |
| [929. Unique Email Addresses](https://leetcode.com/problems/unique-email-addresses/) | Easy | [C](./old-problems/0929/c/solution.c) [C++](./old-problems/0929/solution.cpp) |
| [930. Binary Subarrays With Sum](https://leetcode.com/problems/binary-subarrays-with-sum/) | Medium | [C](./old-problems/0930/c/solution.c) [C++](./old-problems/0930/solution.cpp) |
| [931. Minimum Falling Path Sum](https://leetcode.com/problems/minimum-falling-path-sum/) | Medium | [C++](./problems/0931/solution.cpp) |
| [933. Number of Recent Calls](https://leetcode.com/problems/number-of-recent-calls/) | Easy | [C++](./old-problems/0933/solution.cpp) |
| [934. Shortest Bridge](https://leetcode.com/problems/shortest-bridge/) | Medium | [C](./old-problems/0934/c/solution.c) [C++](./old-problems/0934/solution.cpp) |
| [935. Knight Dialer](https://leetcode.com/problems/knight-dialer/) | Easy | [C](./old-problems/0935/c/solution.c) [C++](./old-problems/0935/solution.cpp) |
| [938. Range Sum of BST](https://leetcode.com/problems/range-sum-of-bst/) | Easy | [C++](./old-problems/0938/solution.cpp) |
| [942. DI String Match](https://leetcode.com/problems/di-string-match/) | Easy | [C](./old-problems/0942/c/solution.c) [C++](./old-problems/0942/solution.cpp) |
| [944. Delete Columns to Make Sorted](https://leetcode.com/problems/delete-columns-to-make-sorted/) | Easy | [C](./old-problems/0944/c/solution.c) [C++](./old-problems/0944/solution.cpp) |
| [945. Minimum Increment to Make Array Unique](https://leetcode.com/problems/minimum-increment-to-make-array-unique/) | Medium | [C](./old-problems/0945/c/solution.c) [C++](./old-problems/0945/solution.cpp) |
| [947. Most Stones Removed with Same Row or Column](https://leetcode.com/problems/most-stones-removed-with-same-row-or-column/) | Medium | [C++](./old-problems/0947/solution.cpp) |
| [948. Bag of Tokens](https://leetcode.com/problems/bag-of-tokens/) | Medium | [C](./old-problems/0948/c/solution.c) [C++](./old-problems/0948/solution.cpp) |
| [950. Reveal Cards In Increasing Order](https://leetcode.com/problems/reveal-cards-in-increasing-order/) | Medium | [C++](./old-problems/0950/solution.cpp) |
| [951. Flip Equivalent Binary Trees](https://leetcode.com/problems/flip-equivalent-binary-trees/) | Medium | [C++](./old-problems/0951/solution.cpp) |
| [959. Regions Cut By Slashes](https://leetcode.com/problems/regions-cut-by-slashes/) | Medium | [C](./old-problems/0959/c/solution.c) [C++](./old-problems/0959/solution.cpp) |
| [961. N-Repeated Element in Size 2N Array](https://leetcode.com/problems/n-repeated-element-in-size-2n-array/) | Easy | [C](./old-problems/0961/c/solution.c) [C++](./old-problems/0961/solution.cpp) |
| [962. Maximum Width Ramp](https://leetcode.com/problems/maximum-width-ramp/) | Medium | [C](./old-problems/0962/c/solution.c) [C++](./old-problems/0962/solution.cpp) |
| [965. Univalued Binary Tree](https://leetcode.com/problems/univalued-binary-tree/) | Easy | [C++](./old-problems/0965/solution.cpp) |
| [966. Vowel Spellchecker](https://leetcode.com/problems/vowel-spellchecker/) | Medium | [C++](./old-problems/0966/solution.cpp) |
| [974. Subarray Sums Divisible by K](https://leetcode.com/problems/subarray-sums-divisible-by-k/) | Medium | [C](./old-problems/0974/c/solution.c) [C++](./old-problems/0974/solution.cpp) |
| [976. Largest Perimeter Triangle](https://leetcode.com/problems/largest-perimeter-triangle/) | Easy | [C](./old-problems/0976/c/solution.c) [C++](./old-problems/0976/solution.cpp) |
| [977. Squares of a Sorted Array](https://leetcode.com/problems/squares-of-a-sorted-array/) | Easy | [C](./old-problems/0977/c/solution.c) [C++](./old-problems/0977/solution.cpp) |
| [979. Distribute Coins in Binary Tree](https://leetcode.com/problems/distribute-coins-in-binary-tree/) | Medium | [C++](./old-problems/0979/solution.cpp) |
| [980. Unique Paths III](https://leetcode.com/problems/unique-paths-iii/) | Hard | [C](./old-problems/0980/c/solution.c) [C++](./old-problems/0980/solution.cpp) |
| [983. Minimum Cost For Tickets](https://leetcode.com/problems/minimum-cost-for-tickets/) | Medium | [C](./old-problems/0983/c/solution.c) [C++](./old-problems/0983/solution.cpp) |
| [988. Smallest String Starting From Leaf](https://leetcode.com/problems/smallest-string-starting-from-leaf/) | Medium | [C++](./old-problems/0988/solution.cpp) |
| [991. Broken Calculator](https://leetcode.com/problems/broken-calculator/) | Medium | [C](./old-problems/0991/c/solution.c) [C++](./old-problems/0991/solution.cpp) |
| [992. Subarrays with K Different Integers](https://leetcode.com/problems/subarrays-with-k-different-integers/) | Hard | [C++](./problems/0992/solution.cpp) |
| [995. Minimum Number of K Consecutive Bit Flips](https://leetcode.com/problems/minimum-number-of-k-consecutive-bit-flips/) | Hard | [C](./old-problems/0995/c/solution.c) [C++](./old-problems/0995/solution.cpp) |
| [997. Find the Town Judge](https://leetcode.com/problems/find-the-town-judge/) | Easy | [C](./old-problems/0997/c/solution.c) [C++](./old-problems/0997/solution.cpp) |
| [1002. Find Common Characters](https://leetcode.com/problems/find-common-characters/) | Easy | [C](./old-problems/1002/c/solution.c) [C++](./old-problems/1002/solution.cpp) |
| [1006. Clumsy Factorial](https://leetcode.com/problems/clumsy-factorial/) | Medium | [C](./old-problems/1006/c/solution.c) [C++](./old-problems/1006/solution.cpp) |
| [1007. Minimum Domino Rotations For Equal Row](https://leetcode.com/problems/minimum-domino-rotations-for-equal-row/) | Medium | [C](./old-problems/1007/c/solution.c) [C++](./old-problems/1007/solution.cpp) |
| [1008. Construct Binary Search Tree from Preorder Traversal](https://leetcode.com/problems/construct-binary-search-tree-from-preorder-traversal/) | Medium | [C++](./old-problems/1008/solution.cpp) |
| [1009. Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/) | Easy | [C](./old-problems/1009/c/solution.c) [C++](./old-problems/1009/solution.cpp) |
| [1011. Capacity To Ship Packages Within D Days](https://leetcode.com/problems/capacity-to-ship-packages-within-d-days/) | Medium | [C](./old-problems/1011/c/solution.c) [C++](./old-problems/1011/solution.cpp) |
| [1014. Best Sightseeing Pair](https://leetcode.com/problems/best-sightseeing-pair/) | Medium | [C](./old-problems/1014/c/solution.c) [C++](./old-problems/1014/solution.cpp) |
| [1015. Smallest Integer Divisible by K](https://leetcode.com/problems/smallest-integer-divisible-by-k/) | Medium | [C](./old-problems/1015/c/solution.c) [C++](./old-problems/1015/solution.cpp) |
| [1018. Binary Prefix Divisible By 5](https://leetcode.com/problems/binary-prefix-divisible-by-5/) | Easy | [C](./old-problems/1018/c/solution.c) [C++](./old-problems/1018/solution.cpp) |
| [1021. Remove Outermost Parentheses](https://leetcode.com/problems/remove-outermost-parentheses/) | Easy | [C](./old-problems/1021/c/solution.c) [C++](./old-problems/1021/solution.cpp) |
| [1022. Sum of Root To Leaf Binary Numbers](https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/) | Easy | [C++](./old-problems/1022/solution.cpp) |
| [1025. Divisor Game](https://leetcode.com/problems/divisor-game/) | Easy | [C](./old-problems/1025/c/solution.c) [C++](./old-problems/1025/solution.cpp) |
| [1026. Maximum Difference Between Node and Ancestor](https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/) | Medium | [C++](./old-problems/1026/solution.cpp) |
| [1028. Recover a Tree From Preorder Traversal](https://leetcode.com/problems/recover-a-tree-from-preorder-traversal/description) | Hard | [C++](./old-problems/1028/solution.cpp) |
| [1038. Binary Search Tree to Greater Sum Tree](https://leetcode.com/problems/binary-search-tree-to-greater-sum-tree/) | Medium | [C++](./old-problems/1038/solution.cpp) |
| [1039. Minimum Score Triangulation of Polygon](https://leetcode.com/problems/minimum-score-triangulation-of-polygon/) | Medium | [C](./old-problems/1039/c/solution.c) [C++](./old-problems/1039/solution.cpp) |
| [1043. Partition Array for Maximum Sum](https://leetcode.com/problems/partition-array-for-maximum-sum/) | Medium | [C](./old-problems/1043/c/solution.c) [C++](./old-problems/1043/solution.cpp) |
| [1046. Last Stone Weight](https://leetcode.com/problems/last-stone-weight/) | Easy | [C](./old-problems/1046/c/solution.c) [C++](./old-problems/1046/solution.cpp) |
| [1047. Remove All Adjacent Duplicates In String](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string/) | Medium | [C](./old-problems/1047/c/solution.c) [C++](./old-problems/1047/solution.cpp) |
| [1048. Longest String Chain](https://leetcode.com/problems/longest-string-chain) | Medium | [C++](./problems/1048/solution.cpp) |
| [1051. Height Checker](https://leetcode.com/problems/height-checker/) | Easy | [C](./old-problems/1051/c/solution.c) [C++](./old-problems/1051/solution.cpp) |
| [1052. Grumpy Bookstore Owner](https://leetcode.com/problems/grumpy-bookstore-owner/) | Medium | [C](./old-problems/1052/c/solution.c) [C++](./old-problems/1052/solution.cpp) |
| [1061. Lexicographically Smallest Equivalent String](https://leetcode.com/problems/lexicographically-smallest-equivalent-string/) | Medium | [C](./old-problems/1061/c/solution.c) [C++](./old-problems/1061/solution.cpp) |
| [1071. Greatest Common Divisor of Strings](https://leetcode.com/problems/greatest-common-divisor-of-strings/) | Easy | [C](./old-problems/1071/c/solution.c) [C++](./old-problems/1071/solution.cpp) |
| [1072. Flip Columns For Maximum Number of Equal Rows](https://leetcode.com/problems/flip-columns-for-maximum-number-of-equal-rows/) | Medium | [C++](./problems/1072/solution.cpp) |
| [1074. Number of Submatrices That Sum to Target](https://leetcode.com/problems/number-of-submatrices-that-sum-to-target/) | Hard | [C](./old-problems/1074/c/solution.c) [C++](./old-problems/1074/solution.cpp) |
| [1079. Letter Tile Possibilities](https://leetcode.com/problems/letter-tile-possibilities/) | Medium | [C](./old-problems/1079/c/solution.c) [C++](./old-problems/1079/solution.cpp) |
| [1080. Insufficient Nodes in Root to Leaf Paths](https://leetcode.com/problems/insufficient-nodes-in-root-to-leaf-paths/) | Medium | [C++](./old-problems/1080/solution.cpp) |
| [1081. Smallest Subsequence of Distinct Characters](https://leetcode.com/problems/smallest-subsequence-of-distinct-characters) | Medium | [C++](./problems/1081/solution.cpp) |
| [1090. Largest Values From Labels](https://leetcode.com/problems/largest-values-from-labels/) | Medium | [C](./old-problems/1090/c/solution.c) [C++](./old-problems/1090/solution.cpp) |
| [1092. Shortest Common Supersequence](https://leetcode.com/problems/shortest-common-supersequence/) | Hard | [C](./old-problems/1092/c/solution.c) [C++](./old-problems/1092/solution.cpp) |
| [1103. Distribute Candies to People](https://leetcode.com/problems/distribute-candies-to-people/) | Easy | [C](./old-problems/1103/c/solution.c) [C++](./old-problems/1103/solution.cpp) |
| [1104. Path In Zigzag Labelled Binary Tree](https://leetcode.com/problems/path-in-zigzag-labelled-binary-tree/) | Medium | [C](./old-problems/1104/c/solution.c) [C++](./old-problems/1104/solution.cpp) |
| [1105. Filling Bookcase Shelves](https://leetcode.com/problems/filling-bookcase-shelves/) | Medium | [C](./old-problems/1105/c/solution.c) [C++](./old-problems/1105/solution.cpp) |
| [1106. Parsing A Boolean Expression](https://leetcode.com/problems/parsing-a-boolean-expression/) | Hard | [C](./old-problems/1106/c/solution.c) [C++](./old-problems/1106/solution.cpp) |
| [1108. Defanging an IP Address](https://leetcode.com/problems/defanging-an-ip-address/) | Easy | [C](./old-problems/1108/c/solution.c) [C++](./old-problems/1108/solution.cpp) |
| [1109. Corporate Flight Bookings](https://leetcode.com/problems/corporate-flight-bookings/) | Medium | [C](./old-problems/1109/c/solution.c) [C++](./old-problems/1109/solution.cpp) |
| [1110. Delete Nodes And Return Forest](https://leetcode.com/problems/delete-nodes-and-return-forest/description) | Medium | [C++](./old-problems/1110/solution.cpp) |
| [1122. Relative Sort Array](https://leetcode.com/problems/relative-sort-array/) | Easy | [C](./old-problems/1122/c/solution.c) [C++](./old-problems/1122/solution.cpp) |
| [1123. Lowest Common Ancestor of Deepest Leaves](https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves/) | Medium | [C++](./old-problems/1123/solution.cpp) |
| [1128. Number of Equivalent Domino Pairs](https://leetcode.com/problems/number-of-equivalent-domino-pairs/) | Easy | [C](./old-problems/1128/c/solution.c) [C++](./old-problems/1128/solution.cpp) |
| [1137. N-th Tribonacci Number](https://leetcode.com/problems/n-th-tribonacci-number/) | Easy | [C](./old-problems/1137/c/solution.c) [C++](./old-problems/1137/solution.cpp) |
| [1140. Stone Game II](https://leetcode.com/problems/stone-game-ii/) | Medium | [C](./old-problems/1140/c/solution.c) [C++](./old-problems/1140/solution.cpp) |
| [1143. Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/) | Medium | [C](./old-problems/1143/c/solution.c) [C++](./old-problems/1143/solution.cpp) |
| [1155. Number of Dice Rolls With Target Sum](https://leetcode.com/problems/number-of-dice-rolls-with-target-sum/) | Medium | [C](./old-problems/1155/c/solution.c) [C++](./old-problems/1155/solution.cpp) |
| [1160. Find Words That Can Be Formed by Characters](https://leetcode.com/problems/find-words-that-can-be-formed-by-characters/) | Easy | [C](./old-problems/1160/c/solution.c) [C++](./old-problems/1160/solution.cpp) |
| [1170. Compare Strings by Frequency of the Smallest Character](https://leetcode.com/problems/compare-strings-by-frequency-of-the-smallest-character/) | Medium | [C++](./old-problems/1170/solution.cpp) |
| [1175. Prime Arrangements](https://leetcode.com/problems/prime-arrangements/) | Easy | [C](./old-problems/1175/c/solution.c) [C++](./old-problems/1175/solution.cpp) |
| [1184. Distance Between Bus Stops](https://leetcode.com/problems/distance-between-bus-stops/) | Easy | [C](./old-problems/1184/c/solution.c) [C++](./old-problems/1184/solution.cpp) |
| [1190. Reverse Substrings Between Each Pair of Parentheses](https://leetcode.com/problems/reverse-substrings-between-each-pair-of-parentheses/) | Medium | [C](./old-problems/1190/c/solution.c) [C++](./old-problems/1190/solution.cpp) |
| [1195. Fizz Buzz Multithreaded](https://leetcode.com/problems/fizz-buzz-multithreaded/) | Medium | [C++](./old-problems/1195/solution.cpp) |
| [1207. Unique Number of Occurrences](https://leetcode.com/problems/unique-number-of-occurrences/) | Easy | [C++](./problems/1207/solution.cpp) |
| [1208. Get Equal Substrings Within Budget](https://leetcode.com/problems/get-equal-substrings-within-budget/) | Medium | [C](./old-problems/1208/c/solution.c) [C++](./old-problems/1208/solution.cpp) |
| [1209. Remove All Adjacent Duplicates in String II](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii/) | Medium | [C](./old-problems/1209/c/solution.c) [C++](./old-problems/1209/solution.cpp) |
| [1210. Minimum Moves to Reach Target with Rotations](https://leetcode.com/problems/minimum-moves-to-reach-target-with-rotations/) | Hard | [C++](./problems/1210/solution.cpp) |
| [1217. Minimum Cost to Move Chips to The Same Position](https://leetcode.com/problems/minimum-cost-to-move-chips-to-the-same-position/) | Easy | [C++](./old-problems/1217/solution.cpp) |
| [1219. Path with Maximum Gold](https://leetcode.com/problems/path-with-maximum-gold/) | Medium | [C](./old-problems/1219/c/solution.c) [C++](./old-problems/1219/solution.cpp) |
| [1220. Count Vowels Permutation](https://leetcode.com/problems/count-vowels-permutation) | Hard | [C](./old-problems/1220/c/solution.c) [C++](./old-problems/1220/solution.cpp) |
| [1221. Split a String in Balanced Strings](https://leetcode.com/problems/split-a-string-in-balanced-strings/) | Easy | [C](./old-problems/1221/c/solution.c) [C++](./old-problems/1221/solution.cpp) |
| [1232. Check If It Is a Straight Line](https://leetcode.com/problems/check-if-it-is-a-straight-line) | Easy | [C++](./problems/1232/solution.cpp) |
| [1233. Remove Sub-Folders from the Filesystem](https://leetcode.com/problems/remove-sub-folders-from-the-filesystem/) | Medium | [C](./old-problems/1233/c/solution.c) [C++](./old-problems/1233/solution.cpp) |
| [1235. Maximum Profit in Job Scheduling](https://leetcode.com/problems/maximum-profit-in-job-scheduling/) | Hard | [C++](./problems/1235/solution.cpp) |
| [1238. Circular Permutation in Binary Representation](https://leetcode.com/problems/circular-permutation-in-binary-representation/) | Medium | [C](./old-problems/1238/c/solution.c) [C++](./old-problems/1238/solution.cpp) |
| [1239. Maximum Length of a Concatenated String with Unique Characters](https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters/) | Medium | [C](./old-problems/1239/c/solution.c) [C++](./old-problems/1239/solution.cpp) |
| [1247. Minimum Swaps to Make Strings Equal](https://leetcode.com/problems/minimum-swaps-to-make-strings-equal/) | Medium | [C](./old-problems/1247/c/solution.c) [C++](./old-problems/1247/solution.cpp) |
| [1248. Count Number of Nice Subarrays](https://leetcode.com/problems/count-number-of-nice-subarrays/) | Medium | [C](./old-problems/1248/c/solution.c) [C++](./old-problems/1248/solution.cpp) |
| [1252. Cells with Odd Values in a Matrix](https://leetcode.com/problems/cells-with-odd-values-in-a-matrix/) | Easy | [C](./old-problems/1252/c/solution.c) [C++](./old-problems/1252/solution.cpp) |
| [1253. Reconstruct a 2-Row Binary Matrix](https://leetcode.com/problems/reconstruct-a-2-row-binary-matrix/) | Medium | [C](./old-problems/1253/c/solution.c) [C++](./old-problems/1253/solution.cpp) |
| [1255. Maximum Score Words Formed by Letters](https://leetcode.com/problems/maximum-score-words-formed-by-letters/) | Hard | [C](./old-problems/1255/c/solution.c) [C++](./old-problems/1255/solution.cpp) |
| [1261. Find Elements in a Contaminated Binary Tree](https://leetcode.com/problems/find-elements-in-a-contaminated-binary-tree/) | Medium | [C++](./old-problems/1261/solution.cpp) |
| [1262. Greatest Sum Divisible by Three](https://leetcode.com/problems/greatest-sum-divisible-by-three/) | Medium | [C](./old-problems/1262/c/solution.c) [C++](./old-problems/1262/solution.cpp) |
| [1266. Minimum Time Visiting All Points](https://leetcode.com/problems/minimum-time-visiting-all-points/) | Easy | [C](./old-problems/1266/c/solution.c) [C++](./old-problems/1266/solution.cpp) |
| [1267. Count Servers that Communicate](https://leetcode.com/problems/count-servers-that-communicate/) | Medium | [C](./old-problems/1267/c/solution.c) [C++](./old-problems/1267/solution.cpp) |
| [1269. Number of Ways to Stay in the Same Place After Some Steps](https://leetcode.com/problems/number-of-ways-to-stay-in-the-same-place-after-some-steps) | Hard | [C++](./problems/1269/solution.cpp) |
| [1275. Find Winner on a Tic Tac Toe Game](https://leetcode.com/problems/find-winner-on-a-tic-tac-toe-game/) | Easy | [C](./old-problems/1275/c/solution.c) [C++](./old-problems/1275/solution.cpp) |
| [1277. Count Square Submatrices with All Ones](https://leetcode.com/problems/count-square-submatrices-with-all-ones/) | Medium | [C](./old-problems/1277/c/solution.c) [C++](./old-problems/1277/solution.cpp) |
| [1281. Subtract the Product and Sum of Digits of an Integer](https://leetcode.com/problems/subtract-the-product-and-sum-of-digits-of-an-integer/) | Easy | [C](./old-problems/1281/c/solution.c) [C++](./old-problems/1281/solution.cpp) |
| [1282. Group the People Given the Group Size They Belong To](https://leetcode.com/problems/group-the-people-given-the-group-size-they-belong-to/) | Medium | [C](./old-problems/1282/c/solution.c) [C++](./old-problems/1282/solution.cpp) |
| [1286. Iterator for Combination](https://leetcode.com/problems/iterator-for-combination/) | Medium | [C++](./old-problems/1286/solution.cpp) |
| [1287. Element Appearing More Than 25% In Sorted Array](https://leetcode.com/problems/element-appearing-more-than-25-in-sorted-array/) | Easy | [C](./old-problems/1287/c/solution.c) [C++](./old-problems/1287/solution.cpp) |
| [1289. Minimum Falling Path Sum II](https://leetcode.com/problems/minimum-falling-path-sum-ii/) | Hard | [C](./old-problems/1289/c/solution.c) [C++](./old-problems/1289/solution.cpp) |
| [1290. Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/) | Easy | [C++](./old-problems/1290/solution.cpp) |
| [1291. Sequential Digits](https://leetcode.com/problems/sequential-digits/) | Medium | [C](./old-problems/1291/c/solution.c) [C++](./old-problems/1291/solution.cpp) |
| [1295. Find Numbers with Even Number of Digits](https://leetcode.com/problems/find-numbers-with-even-number-of-digits/) | Easy | [C](./old-problems/1295/c/solution.c) [C++](./old-problems/1295/solution.cpp) |
| [1298. Maximum Candies You Can Get from Boxes](https://leetcode.com/problems/maximum-candies-you-can-get-from-boxes/) | Hard | [C](./old-problems/1298/c/solution.c) [C++](./old-problems/1298/solution.cpp) |
| [1299. Replace Elements with Greatest Element on Right Side](https://leetcode.com/problems/replace-elements-with-greatest-element-on-right-side/) | Easy | [C](./old-problems/1299/c/solution.c) [C++](./old-problems/1299/solution.cpp) |
| [1302. Deepest Leaves Sum](https://leetcode.com/problems/deepest-leaves-sum/) | Medium | [C++](./old-problems/1302/solution.cpp) |
| [1304. Find N Unique Integers Sum up to Zero](https://leetcode.com/problems/find-n-unique-integers-sum-up-to-zero/) | Easy | [C](./old-problems/1304/c/solution.c) [C++](./old-problems/1304/solution.cpp) |
| [1305. All Elements in Two Binary Search Trees](https://leetcode.com/problems/all-elements-in-two-binary-search-trees/) | Medium | [C++](./old-problems/1305/solution.cpp) |
| [1309. Decrypt String from Alphabet to Integer Mapping](https://leetcode.com/problems/decrypt-string-from-alphabet-to-integer-mapping/) | Easy | [C](./old-problems/1309/c/solution.c) [C++](./old-problems/1309/solution.cpp) |
| [1310. XOR Queries of a Subarray](https://leetcode.com/problems/xor-queries-of-a-subarray/) | Medium | [C](./old-problems/1310/c/solution.c) [C++](./old-problems/1310/solution.cpp) |
| [1313. Decompress Run-Length Encoded List](https://leetcode.com/problems/decompress-run-length-encoded-list/) | Easy | [C](./old-problems/1313/c/solution.c) [C++](./old-problems/1313/solution.cpp) |
| [1314. Matrix Block Sum](https://leetcode.com/problems/matrix-block-sum/) | Medium | [C](./old-problems/1314/c/solution.c) [C++](./old-problems/1314/solution.cpp) |
| [1315. Sum of Nodes with Even-Valued Grandparent](https://leetcode.com/problems/sum-of-nodes-with-even-valued-grandparent/) | Medium | [C++](./old-problems/1315/solution.cpp) |
| [1317. Convert Integer to the Sum of Two No-Zero Integers](https://leetcode.com/problems/convert-integer-to-the-sum-of-two-no-zero-integers/) | Easy | [C](./old-problems/1317/c/solution.c) [C++](./old-problems/1317/solution.cpp) |
| [1323. Maximum 69 Number](https://leetcode.com/problems/maximum-69-number/) | Easy | [C](./old-problems/1323/c/solution.c) [C++](./old-problems/1323/solution.cpp) |
| [1325. Delete Leaves With a Given Value](https://leetcode.com/problems/delete-leaves-with-a-given-value/) | Medium | [C++](./old-problems/1325/solution.cpp) |
| [1329. Sort the Matrix Diagonally](https://leetcode.com/problems/sort-the-matrix-diagonally/) | Medium | [C](./old-problems/1329/c/solution.c) [C++](./old-problems/1329/solution.cpp) |
| [1331. Rank Transform of an Array](https://leetcode.com/problems/rank-transform-of-an-array/) | Easy | [C](./old-problems/1331/c/solution.c) [C++](./old-problems/1331/solution.cpp) |
| [1332. Remove Palindromic Subsequences](https://leetcode.com/problems/remove-palindromic-subsequences/) | Medium | [C](./old-problems/1332/c/solution.c) [C++](./old-problems/1332/solution.cpp) |
| [1334. Find the City With the Smallest Number of Neighbors at a Threshold Distance](https://leetcode.com/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance/) | Medium | [C](./old-problems/1334/c/solution.c) [C++](./old-problems/1334/solution.cpp) |
| [1337. The K Weakest Rows in a Matrix](https://leetcode.com/problems/the-k-weakest-rows-in-a-matrix) | Easy | [C++](./problems/1337/solution.cpp) |
| [1342. Number of Steps to Reduce a Number to Zero](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-to-zero/) | Easy | [C](./old-problems/1342/c/solution.c) [C++](./old-problems/1342/solution.cpp) |
| [1346. Check If N and Its Double Exist](https://leetcode.com/problems/check-if-n-and-its-double-exist/) | Easy | [C++](./old-problems/1346/solution.cpp) |
| [1347. Minimum Number of Steps to Make Two Strings Anagram](https://leetcode.com/problems/minimum-number-of-steps-to-make-two-strings-anagram/) | Medium | [C](./old-problems/1347/c/solution.c) [C++](./old-problems/1347/solution.cpp) |
| [1348. Tweet Counts Per Frequency](https://leetcode.com/problems/tweet-counts-per-frequency/) | Medium | [C++](./old-problems/1348/solution.cpp) |
| [1351. Count Negative Numbers in a Sorted Matrix](https://leetcode.com/problems/count-negative-numbers-in-a-sorted-matrix/) | Easy | [C](./old-problems/1351/c/solution.c) [C++](./old-problems/1351/solution.cpp) |
| [1352. Product of the Last K Numbers](https://leetcode.com/problems/product-of-the-last-k-numbers/) | Medium | [C++](./old-problems/1352/solution.cpp) |
| [1353. Maximum Number of Events That Can Be Attended](https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended/) | Medium | [C](./old-problems/1353/c/solution.c) [C++](./old-problems/1353/solution.cpp) |
| [1356. Sort Integers by The Number of 1 Bits](https://leetcode.com/problems/sort-integers-by-the-number-of-1-bits) | Easy | [C++](./problems/1356/solution.cpp) |
| [1357. Apply Discount Every n Orders](https://leetcode.com/problems/apply-discount-every-n-orders/) | Medium | [C++](./old-problems/1357/solution.cpp) |
| [1361. Validate Binary Tree Nodes](https://leetcode.com/problems/validate-binary-tree-nodes) | Medium | [C](./old-problems/1361/c/solution.c) [C++](./old-problems/1361/solution.cpp) |
| [1365. How Many Numbers Are Smaller Than the Current Number](https://leetcode.com/problems/how-many-numbers-are-smaller-than-the-current-number/) | Easy | [C++](./old-problems/1365/solution.cpp) |
| [1366. Rank Teams by Votes](https://leetcode.com/problems/rank-teams-by-votes/) | Medium | [C](./old-problems/1366/c/solution.c) [C++](./old-problems/1366/solution.cpp) |
| [1367. Linked List in Binary Tree](https://leetcode.com/problems/linked-list-in-binary-tree/) | Medium | [C++](./old-problems/1367/solution.cpp) |
| [1370. Increasing Decreasing String](https://leetcode.com/problems/increasing-decreasing-string/) | Easy | [C](./old-problems/1370/c/solution.c) [C++](./old-problems/1370/solution.cpp) |
| [1371. Find the Longest Substring Containing Vowels in Even Counts](https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts/) | Medium | [C](./old-problems/1371/c/solution.c) [C++](./old-problems/1371/solution.cpp) |
| [1374. Generate a String With Characters That Have Odd Counts](https://leetcode.com/problems/generate-a-string-with-characters-that-have-odd-counts/) | Easy | [C](./old-problems/1374/c/solution.c) [C++](./old-problems/1374/solution.cpp) |
| [1379. Find a Corresponding Node of a Binary Tree in a Clone of That Tree](https://leetcode.com/problems/find-the-longest-substring-containing-vowels-in-even-counts/) | Medium | [C](./old-problems/1371/c/solution.c) [C++](./old-problems/1371/solution.cpp) |
| [1380. Lucky Numbers in a Matrix](https://leetcode.com/problems/lucky-numbers-in-a-matrix/) | Easy | [C](./old-problems/1380/c/solution.c) [C++](./old-problems/1380/solution.cpp) |
| [1381. Design a Stack With Increment Operation](https://leetcode.com/problems/design-a-stack-with-increment-operation/) | Medium | [C++](./old-problems/1381/solution.cpp) |
| [1382. Balance a Binary Search Tree](https://leetcode.com/problems/balance-a-binary-search-tree/) | Medium | [C++](./old-problems/1382/solution.cpp) |
| [1394. Find Lucky Integer in an Array](https://leetcode.com/problems/find-lucky-integer-in-an-array/) | Easy | [C](./old-problems/1394/c/solution.c) [C++](./old-problems/1394/solution.cpp) |
| [1389. Create Target Array in the Given Order](https://leetcode.com/problems/create-target-array-in-the-given-order/) | Medium | [C](./old-problems/1389/c/solution.c) [C++](./old-problems/1389/solution.cpp) |
| [1395. Count Number of Teams](https://leetcode.com/problems/count-number-of-teams/) | Medium | [C](./old-problems/1395/c/solution.c) [C++](./old-problems/1395/solution.cpp) |
| [1396. Design Underground System](https://leetcode.com/problems/design-underground-system/) | Medium | [C++](./old-problems/1396/solution.cpp) |
| [1399. Count Largest Group](https://leetcode.com/problems/count-largest-group/) | Easy | [C++](./old-problems/1399/solution.cpp) |
| [1402. Reducing Dishes](https://leetcode.com/problems/reducing-dishes/) | Hard | [C](./old-problems/1402/c/solution.c) [C++](./old-problems/1402/solution.cpp) |
| [1403. Minimum Subsequence in Non-Increasing Order](https://leetcode.com/problems/minimum-subsequence-in-non-increasing-order/) | Easy | [C](./old-problems/1403/c/solution.c) [C++](./old-problems/1403/solution.cpp) |
| [1404. Number of Steps to Reduce a Number in Binary Representation to One](https://leetcode.com/problems/number-of-steps-to-reduce-a-number-in-binary-representation-to-one/) | Medium | [C](./old-problems/1404/c/solution.c) [C++](./old-problems/1404/solution.cpp) |
| [1405. Longest Happy String](https://leetcode.com/problems/longest-happy-string/) | Medium | [C](./old-problems/1405/c/solution.c) [C++](./old-problems/1405/solution.cpp) |
| [1408. String Matching in an Array](https://leetcode.com/problems/string-matching-in-an-array/) | Easy | [C](./old-problems/1408/c/solution.c) [C++](./old-problems/1408/solution.cpp) |
| [1409. Queries on a Permutation With Key](https://leetcode.com/problems/queries-on-a-permutation-with-key/) | Medium | [C](./old-problems/1409/c/solution.c) [C++](./old-problems/1409/solution.cpp) |
| [1415. The k-th Lexicographical String of All Happy Strings of Length n](https://leetcode.com/problems/the-k-th-lexicographical-string-of-all-happy-strings-of-length-n/) | Medium | [C](./old-problems/1415/c/solution.c) [C++](./old-problems/1415/solution.cpp) |
| [1418. Display Table of Food Orders in a Restaurant](https://leetcode.com/problems/display-table-of-food-orders-in-a-restaurant/) | Medium | [C++](./old-problems/1418/solution.cpp) |
| [1419. Minimum Number of Frogs Croaking](https://leetcode.com/problems/minimum-number-of-frogs-croaking/) | Medium | [C](./old-problems/1419/c/solution.c) [C++](./old-problems/1419/solution.cpp) |
| [1422. Maximum Score After Splitting a String](https://leetcode.com/problems/maximum-score-after-splitting-a-string/) | Easy | [C](./old-problems/1422/c/solution.c) [C++](./old-problems/1422/solution.cpp) |
| [1424. Diagonal Traverse II](https://leetcode.com/problems/diagonal-traverse-ii/) | Medium | [C++](./problems/1424/solution.cpp) |
| [1425. Constrained Subsequence Sum](https://leetcode.com/problems/constrained-subsequence-sum) | Hard | [C++](./problems/1425/solution.cpp) |
| [1431. Kids With the Greatest Number of Candies](https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/) | Easy | [C](./old-problems/1431/c/solution.c) [C++](./old-problems/1431/solution.cpp) |
| [1432. Max Difference You Can Get From Changing an Integer](https://leetcode.com/problems/max-difference-you-can-get-from-changing-an-integer/) | Medium | [C](./old-problems/1432/c/solution.c) [C++](./old-problems/1432/solution.cpp) |
| [1436. Destination City](https://leetcode.com/problems/destination-city/) | Easy | [C++](./problems/1436/solution.cpp) |
| [1437. Check If All 1's Are at Least Length K Places Away](https://leetcode.com/problems/check-if-all-1s-are-at-least-length-k-places-away/) | Easy | [C](./old-problems/1437/c/solution.c) [C++](./old-problems/1437/solution.cpp) |
| [1438. Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit](https://leetcode.com/problems/longest-continuous-subarray-with-absolute-diff-less-than-or-equal-to-limit/) | Medium | [C](./old-problems/1438/c/solution.c) [C++](./old-problems/1438/solution.cpp) |
| [1441. Build an Array With Stack Operations](https://leetcode.com/problems/build-an-array-with-stack-operations) | Medium | [C++](./problems/1441/solution.cpp) |
| [1442. Count Triplets That Can Form Two Arrays of Equal XOR](https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor/) | Medium | [C](./old-problems/1442/c/solution.c) [C++](./old-problems/1442/solution.cpp) |
| [1448. Count Good Nodes in Binary Tree](https://leetcode.com/problems/count-good-nodes-in-binary-tree/) | Medium | [C++](./old-problems/1448/solution.cpp) |
| [1450. Number of Students Doing Homework at a Given Time](https://leetcode.com/problems/number-of-students-doing-homework-at-a-given-time/) | Easy | [C](./old-problems/1450/c/solution.c) [C++](./old-problems/1450/solution.cpp) |
| [1455. Check If a Word Occurs As a Prefix of Any Word in a Sentence](https://leetcode.com/problems/check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence/) | Easy | [C](./old-problems/1455/c/solution.c) [C++](./old-problems/1455/solution.cpp) |
| [1457. Pseudo-Palindromic Paths in a Binary Tree](https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree/) | Medium | [C++](./old-problems/1457/solution.cpp) |
| [1458. Max Dot Product of Two Subsequences](https://leetcode.com/problems/max-dot-product-of-two-subsequences) | Hard | [C++](./problems/1458/solution.cpp) |
| [1460. Make Two Arrays Equal by Reversing Subarrays](https://leetcode.com/problems/make-two-arrays-equal-by-reversing-subarrays/) | Easy | [C](./old-problems/1460/c/solution.c) [C++](./old-problems/1460/solution.cpp) |
| [1462. Course Schedule IV](https://leetcode.com/problems/course-schedule-iv/) | Medium | [C](./old-problems/1462/c/solution.c) [C++](./old-problems/1462/solution.cpp) |
| [1464. Maximum Product of Two Elements in an Array](https://leetcode.com/problems/maximum-product-of-two-elements-in-an-array/) | Easy | [C](./old-problems/1464/c/solution.c) [C++](./old-problems/1464/solution.cpp) |
| [1470. Shuffle the Array](https://leetcode.com/problems/shuffle-the-array/) | Easy | [C](./old-problems/1470/c/solution.c) [C++](./old-problems/1470/solution.cpp) |
| [1472. Design Browser History](https://leetcode.com/problems/design-browser-history/) | Medium | [C++](./old-problems/1472/solution.cpp) |
| [1475. Final Prices With a Special Discount in a Shop](https://leetcode.com/problems/final-prices-with-a-special-discount-in-a-shop/) | Easy | [C](./old-problems/1475/c/solution.c) [C++](./old-problems/1475/solution.cpp) |
| [1476. Subrectangle Queries](https://leetcode.com/problems/subrectangle-queries/) | Medium | [C++](./old-problems/1476/solution.cpp) |
| [1480. Running Sum of 1d Array](https://leetcode.com/problems/running-sum-of-1d-array/) | Easy | [C](./old-problems/1480/c/solution.c) [C++](./old-problems/1480/solution.cpp) |
| [1481. Least Number of Unique Integers after K Removals](https://leetcode.com/problems/least-number-of-unique-integers-after-k-removals/) | Medium | [C++](./problems/1481/solution.cpp) |
| [1482. Minimum Number of Days to Make m Bouquets](https://leetcode.com/problems/minimum-number-of-days-to-make-m-bouquets/) | Medium | [C](./old-problems/1482/c/solution.c) [C++](./old-problems/1482/solution.cpp) |
| [1486. XOR Operation in an Array](https://leetcode.com/problems/xor-operation-in-an-array/) | Easy | [C](./old-problems/1486/c/solution.c) [C++](./old-problems/1486/solution.cpp) |
| [1488. Avoid Flood in The City](https://leetcode.com/problems/avoid-flood-in-the-city/) | Medium | [C++](./old-problems/1488/solution.cpp) |
| [1493. Longest Subarray of 1's After Deleting One Element](https://leetcode.com/problems/longest-subarray-of-1s-after-deleting-one-element/) | Medium | [C](./old-problems/1493/c/solution.c) [C++](./old-problems/1493/solution.cpp) |
| [1496. Path Crossing](https://leetcode.com/problems/path-crossing/) | Easy | [C++](./problems/1496/solution.cpp) |
| [1497. Check If Array Pairs Are Divisible by k](https://leetcode.com/problems/check-if-array-pairs-are-divisible-by-k/) | Medium | [C](./old-problems/1497/c/solution.c) [C++](./old-problems/1497/solution.cpp) |
| [1498. Number of Subsequences That Satisfy the Given Sum Condition](https://leetcode.com/problems/number-of-subsequences-that-satisfy-the-given-sum-condition/) | Medium | [C](./old-problems/1498/c/solution.c) [C++](./old-problems/1498/solution.cpp) |
| [1503. Last Moment Before All Ants Fall Out of a Plank](https://leetcode.com/problems/last-moment-before-all-ants-fall-out-of-a-plank) | Medium | [C](./old-problems/1503/c/solution.c) [C++](./old-problems/1503/solution.cpp) |
| [1507. Reformat Date](https://leetcode.com/problems/reformat-date/) | Easy | [C](./old-problems/1507/c/solution.c) [C++](./old-problems/1507/solution.cpp) |
| [1508. Range Sum of Sorted Subarray Sums](https://leetcode.com/problems/range-sum-of-sorted-subarray-sums/) | Medium | [C](./old-problems/1508/c/solution.c) [C++](./old-problems/1508/solution.cpp) |
| [1509. Minimum Difference Between Largest and Smallest Value in Three Moves](https://leetcode.com/problems/minimum-difference-between-largest-and-smallest-value-in-three-moves/) | Medium | [C](./old-problems/1509/c/solution.c) [C++](./old-problems/1509/solution.cpp) |
| [1512. Number of Good Pairs](https://leetcode.com/problems/number-of-good-pairs) | Easy | [C](./old-problems/1512/c/solution.c) [C+