LeetCode
This repo is build to collect leetcode algorithms we write.
Completion Statistic:
- Python: 362
- JavaScript: 20
- Java: 3
- C(++): 41
Total completed: 392
Solutions
| Title | Solutions | Difficulty |
|---|---|---|
| 1. Two Sum | Python, JavaScript, C(++) | Easy |
| 2. Add Two Numbers | Python, JavaScript | Medium |
| 3. Longest Substring Without Repeating Characters | Python, JavaScript, C(++) | Medium |
| 4. Median of Two Sorted Arrays | JavaScript, C(++) | Hard |
| 5. Longest Palindromic Substring | Python, JavaScript, C(++) | Medium |
| 6. ZigZag Conversion | Python, C(++) | Medium |
| 7. Reverse Integer | Python | Easy |
| 8. String to Integer (atoi) | Python | Medium |
| 9. Palindrome Number | Python | Easy |
| 10. Regular Expression Matching | Python, JavaScript | Hard |
| 11. Container With Most Water | Python | Medium |
| 12. Integer to Roman | Python | Medium |
| 13. Roman to Integer | Python, JavaScript | Easy |
| 14. Longest Common Prefix | Python, C(++) | Easy |
| 15. 3Sum | Python | Medium |
| 16. 3Sum Closest | Python | Medium |
| 17. Letter Combinations of a Phone Number | Python | Medium |
| 18. 4Sum | Python | Medium |
| 19. Remove Nth Node From End of List | Python | Medium |
| 20. Valid Parentheses | Python, JavaScript | Easy |
| 21. Merge Two Sorted Lists | Python | Easy |
| 22. Generate Parentheses | Python | Medium |
| 23. Merge k Sorted Lists | Python | Hard | | 24. Swap Nodes in Pairs | Python | Medium | | 25. Reverse Nodes in k-Group | Python | Hard | | 26. Remove Duplicates from Sorted Array | Python, JavaScript | Easy |
| 27. Remove Element | Python | Easy | | 28. Implement strStr() | Python | Easy | | 29. Divide Two Integers | Python | Medium | | 30. Substring with Concatenation of All Words | Python | Hard | | 31. Next Permutation | Python | Medium | | 32. Longest Valid Parentheses | Python | Hard | | 33. Search in Rotated Sorted Array | Python, JavaScript, C(++) | Medium | | 34. Find First and Last Position of Element in Sorted Array | Python, JavaScript | Medium | | 35. Search Insert Position | Python | Easy | | 36. Valid Sudoku | Python | Medium | | 37. Sudoku Solver | Python, Java | Hard | | 38. Count and Say | Python | Easy | | 39. Combination Sum | Python | Medium | | 40. Combination Sum II | Python | Medium | | 41. First Missing Positive | Python | Hard | | 42. Trapping Rain Water | Python | Hard | | 43. Multiply Strings | Python, C(++) | Medium | | 44. Wildcard Matching | Python | Hard | | 45. Jump Game II | Python | Hard | | 46. Permutations | Python | Medium | | 47. Permutations II | Python | Medium | | 48. Rotate Image | Python | Medium | | 49. Group Anagrams | Python, Java | Medium | | 50. Pow(x, n) | Python | Medium | | 51. N-Queens | Python | Hard | | 52. N-Queens II | Python | Hard | | 53. Maximum Subarray | Python, C(++) | Easy | | 54. Spiral Matrix | Python | Medium | | 55. Jump Game | Python | Medium | | 56. Merge Intervals | Python, C(++) | Medium | | 57. Insert Interval | Python, C(++) | Hard | | 58. Length of Last Word | Python | Easy | | 59. Spiral Matrix II | Python | Medium | | 60. Permutation Sequence | Python | Medium | | 61. Rotate List | Python | Medium | | 62. Unique Paths | Python | Medium | | 63. Unique Paths II | Python | Medium | | 64. Minimum Path Sum | Python | Medium | | 66. Plus One | Python | Easy | | 67. Add Binary | Python | Easy | | 68. Text Justification | Python | Hard | | 69. Sqrt(x) | Python | Easy | | 70. Climbing Stairs | Python | Easy | | 71. Simplify Path | Python | Medium | | 72. Edit Distance | Python | Hard | | 73. Set Matrix Zeroes | Python | Medium | | 74. Search a 2D Matrix | Python, JavaScript | Medium | | 75. Sort Colors | Python | Medium | | 76. Minimum Window Substring | Python, C(++) | Hard | | 77. Combinations | Python | Medium | | 78. Subsets | Python | Medium | | 79. Word Search | Python | Medium | | 80. Remove Duplicates from Sorted Array II | Python | Medium | | 81. Search in Rotated Sorted Array II | Python | Medium | | 82. Remove Duplicates from Sorted List II | Python | Medium | | 83. Remove Duplicates from Sorted List | Python | Easy | | 84. Largest Rectangle in Histogram | Python | Hard | | 86. Partition List | Python | Medium | | 88. Merge Sorted Array | Python, C(++) | Easy | | 89. Gray Code | Python | Medium | | 90. Subsets II | Python | Medium | | 91. Decode Ways | Python | Medium | | 92. Reverse Linked List II | Python | Medium | | 93. Restore IP Addresses | Python | Medium | | 94. Binary Tree Inorder Traversal | Python | Medium | | 95. Unique Binary Search Trees II | Python | Medium | | 96. Unique Binary Search Trees | Python | Medium | | 98. Validate Binary Search Tree | Python | Medium | | 100. Same Tree | Python | Easy | | 101. Symmetric Tree | Python | Easy | | 102. Binary Tree Level Order Traversal | Python, C(++) | Medium | | 103. Binary Tree Zigzag Level Order Traversal | Python | Medium | | 104. Maximum Depth of Binary Tree | Python | Easy | | 105. Construct Binary Tree from Preorder and Inorder Traversal | Python | Medium | | 106. Construct Binary Tree from Inorder and Postorder Traversal | Python | Medium | | 107. Binary Tree Level Order Traversal II | Python | Easy | | 108. Convert Sorted Array to Binary Search Tree | Python | Easy | | 109. Convert Sorted List to Binary Search Tree | Python | Medium | | 110. Balanced Binary Tree | Python | Easy | | 111. Minimum Depth of Binary Tree | Python | Easy | | 112. Path Sum | Python | Easy | | 113. Path Sum II | Python | Medium | | 114. Flatten Binary Tree to Linked List | Python | Medium | | 115. Distinct Subsequences | Python | Hard | | 116. Populating Next Right Pointers in Each Node | Python | Medium | | 120. Triangle | Python | Medium | | 121. Best Time to Buy and Sell Stock | Python | Easy | | 122. Best Time to Buy and Sell Stock II | Python | Easy | | 123. Best Time to Buy and Sell Stock III | Python | Hard | | 124. Binary Tree Maximum Path Sum | Python | Hard | | 125. Valid Palindrome | Python | Easy | | 128. Longest Consecutive Sequence | Python | Hard | | 129. Sum Root to Leaf Numbers | Python | Medium | | 130. Surrounded Regions | Python | Medium | | 131. Palindrome Partitioning | Python | Medium | | 132. Palindrome Partitioning II | Python | Hard | | 133. Clone Graph | Python | Medium | | 134. Gas Station | Python | Medium | | 136. Single Number | Python | Easy | | 137. Single Number II | Python | Medium | | 139. Word Break | Python, C(++) | Medium | | 140. Word Break II | Python | Hard | | 141. Linked List Cycle | Python | Easy | | 142. Linked List Cycle II | Python | Medium | | 145. Binary Tree Postorder Traversal | Python | Hard | | 146. LRU Cache | Python | Medium | | 147. Insertion Sort List | Python | Medium | | 148. Sort List | Python | Medium | | 149. Max Points on a Line | Python | Hard | | 150. Evaluate Reverse Polish Notation | Python | Medium | | 151. Reverse Words in a String | C(++) | Medium | | 153. Find Minimum in Rotated Sorted Array | Python | Medium | | 154. Find Minimum in Rotated Sorted Array II | Python | Hard | | 155. Min Stack | Python | Easy | | 162. Find Peak Element | Python | Medium | | 165. Compare Version Numbers | Python | Medium | | 166. Fraction to Recurring Decimal | Python | Medium | | 167. Two Sum II - Input array is sorted | Python | Easy | | 169. Majority Element | Python, JavaScript | Easy | | 173. Binary Search Tree Iterator | Python, C(++) | Medium | | 174. Dungeon Game | Python | Hard | | 179. Largest Number | Python | Medium | | 187. Repeated DNA Sequences | Python | Medium | | 189. Rotate Array | Python | Easy | | 190. Reverse Bits | C(++) | Easy | | 191. Number of 1 Bits | Python | Easy | | 198. House Robber | Python | Easy | | 200. Number of Islands | Python | Medium | | 201. Bitwise AND of Numbers Range | Python | Medium | | 202. Happy Number | Python | Easy | | 204. Count Primes | Python | Easy | | 205. Isomorphic Strings | Python, JavaScript | Easy | | 206. Reverse Linked List | Python | Easy | | 207. Course Schedule | Python | Medium | | 208. Implement Trie (Prefix Tree) | Python | Medium | | 209. Minimum Size Subarray Sum | Python | Medium | | 210. Course Schedule II | Python | Medium | | 211. Add and Search Word - Data structure design | Python | Medium | | 212. Word Search II | Python | Hard | | 213. House Robber II | Python | Medium | | 214. Shortest Palindrome | Python | Hard | | 215. Kth Largest Element in an Array | Python | Medium | | 217. Contains Duplicate | Python | Easy | | 219. Contains Duplicate II | Python | Easy | | 220. Contains Duplicate III | Python | Medium | | 221. Maximal Square | Python | Medium | | 223. Rectangle Area | Python | Medium | | 224. Basic Calculator | C(++) | Hard | | 225. Implement Stack using Queues | Python | Easy | | 226. Invert Binary Tree | Python | Easy | | 227. Basic Calculator II | Python | Medium | | 228. Summary Ranges | Python | Medium | | 230. Kth Smallest Element in a BST | Python | Medium | | 231. Power of Two | Python | Easy | | 232. Implement Queue using Stacks | Python, Java | Easy | | 235. Lowest Common Ancestor of a Binary Search Tree | Python | Easy | | 236. Lowest Common Ancestor of a Binary Tree | Python | Medium | | 237. Delete Node in a Linked List | Python | Easy | | 238. Product of Array Except Self | Python | Medium | | 239. Sliding Window Maximum | Python | Hard | | 240. Search a 2D Matrix II | Python | Medium | | 241. Different Ways to Add Parentheses | Python | Medium | | 257. Binary Tree Paths | Python | Easy | | 260. Single Number III | Python | Medium | | 263. Ugly Number | Python | Easy | | 264. Ugly Number II | Python | Medium | | 268. Missing Number | Python | Easy | | 273. Integer to English Words | Python | Hard | | 274. H-Index | Python | Medium | | 275. H-Index II | Python | Medium | | 278. First Bad Version | Python, C(++) | Easy | | 279. Perfect Squares | Python | Medium | | 283. Move Zeroes | Python | Easy | | 287. Find the Duplicate Number | Python | Medium | | 289. Game of Life | Python | Medium | | 290. Word Pattern | Python | Easy | | 299. Bulls and Cows | Python, JavaScript | Easy | | 300. Longest Increasing Subsequence | Python | Medium | | 303. Range Sum Query - Immutable | Python | Easy | | 304. Range Sum Query 2D - Immutable | Python | Medium | | 305. Number of Islands II | Python | Hard | | 307. Range Sum Query - Mutable | Python | Medium | | 312. Burst Balloons | C(++) | Hard | | 319. Bulb Switcher | Python | Medium | | 322. Coin Change | Python | Medium | | 326. Power of Three | C(++) | Easy | | 329. Longest Increasing Path in a Matrix | Python | Hard | | 331. Verify Preorder Serialization of a Binary Tree | Python | Medium | | 332. Reconstruct Itinerary | Python | Medium | | 337. House Robber III | Python | Medium | | 338. Counting Bits | Python | Medium | | 341. Flatten Nested List Iterator | Python | Medium | | 343. Integer Break | Python | Medium | | 347. Top K Frequent Elements | Python | Medium | | 349. Intersection of Two Arrays | Python | Easy | | 350. Intersection of Two Arrays II | Python | Easy | | 354. Russian Doll Envelopes | Python | Hard | | 355. Design Twitter | Python | Medium | | 371. Sum of Two Integers | Python | Easy | | 376. Wiggle Subsequence | Python | Medium | | 378. Kth Smallest Element in a Sorted Matrix | Python | Medium | | 387. First Unique Character in a String | Python | Easy | | 392. Is Subsequence | Python | Easy | | 394. Decode String | Python | Medium | | 402. Remove K Digits | Python | Medium | | 404. Sum of Left Leaves | Python, C(++) | Easy | | 405. Convert a Number to Hexadecimal | Python | Easy | | 406. Queue Reconstruction by Height | Python | Medium | | 409. Longest Palindrome | Python | Easy | | 416. Partition Equal Subset Sum | Python | Medium | | 417. Pacific Atlantic Water Flow | Python | Medium | | 421. Maximum XOR of Two Numbers in an Array | Python | Medium | | 437. Path Sum III | Python | Easy | | 438. Find All Anagrams in a String | C(++) | Medium | | 441. Arranging Coins | Python | Easy | | 442. Find All Duplicates in an Array | Python | Medium | | 443. String Compression | Python | Easy | | 445. Add Two Numbers II | Python | Medium | | 452. Minimum Number of Arrows to Burst Balloons | Python | Medium | | 454. 4Sum II | Python, C(++) | Medium | | 455. Assign Cookies | Python | Easy | | 458. Poor Pigs | Python | Hard | | 459. Repeated Substring Pattern | Python | Easy | | 461. Hamming Distance | Python | Easy | | 462. Minimum Moves to Equal Array Elements II | Python | Medium | | 463. Island Perimeter | Python | Easy | | 464. Can I Win | Python | Medium | | 465. Optimal Account Balancing | Python | Hard | | 473. Matchsticks to Square | Python | Medium | | 475. Heaters | Python | Easy | | 476. Number Complement | Python | Easy | | 477. Total Hamming Distance | Python | Medium | | 481. Magical String | Python | Medium | | 486. Predict the Winner | Python | Medium | | 496. Next Greater Element I | Python | Easy | | 504. Base 7 | Python | Easy | | 507. Perfect Number | Python | Easy | | 509. Fibonacci Number | JavaScript | Easy | | 513. Find Bottom Left Tree Value | Python | Medium | | 518. Coin Change 2 | Python | Medium | | 525. Contiguous Array | Python | Medium | | 526. Beautiful Arrangement | Python | Medium | | 530. Minimum Absolute Difference in BST | C(++) | Easy | | 542. 01 Matrix | Python | Medium | | 543. Diameter of Binary Tree | Python | Easy | | 547. Friend Circles | Python, C(++) | Medium | | 551. Student Attendance Record I | Python | Easy | | 554. Brick Wall | Python | Medium | | 559. Maximum Depth of N-ary Tree | Python | Easy | | 560. Subarray Sum Equals K | Python | Medium | | 561. Array Partition I | Python | Easy | | 566. Reshape the Matrix | Python | Easy | | 576. Out of Boundary Paths | Python | Medium | | 589. N-ary Tree Preorder Traversal | Python | Easy | | 590. N-ary Tree Postorder Traversal | Python | Easy | | 599. Minimum Index Sum of Two Lists | Python | Easy | | 606. Construct String from Binary Tree | Python, C(++) | Easy | | 617. Merge Two Binary Trees | Python | Easy | | 621. Task Scheduler | C(++) | Medium | | 628. Maximum Product of Three Numbers | Python | Easy | | 633. Sum of Square Numbers | Python | Easy | | 637. Average of Levels in Binary Tree | C(++) | Easy | | 648. Replace Words | Python | Medium | | 650. 2 Keys Keyboard | Python | Medium | | 652. Find Duplicate Subtrees | Python, C(++) | Medium | | 654. Maximum Binary Tree | Python | Medium | | 655. Print Binary Tree | Python | Medium | | 657. Robot Return to Origin | Python | Easy | | 665. Non-decreasing Array | JavaScript | Easy | | 669. Trim a Binary Search Tree | Python | Easy | | 671. Second Minimum Node In a Binary Tree | Python | Easy | | 673. Number of Longest Increasing Subsequence | Python | Medium | | 674. Longest Continuous Increasing Subsequence | Python | Easy | | 675. Cut Off Trees for Golf Event | Python | Hard | | 677. Map Sum Pairs | Python | Medium | | 680. Valid Palindrome II | Python | Easy | | 682. Baseball Game | Python | Easy | | 687. Longest Univalue Path | Python | Easy | | 690. Employee Importance | Python | Easy | | 692. Top K Frequent Words | Python | Medium | | 697. Degree of an Array | Python | Easy | | 701. Insert into a Binary Search Tree | Python | Medium | | 703. Kth Largest Element in a Stream | Python | Easy | | 704. Binary Search | Python | Easy | | 705. Design HashSet | Python | Easy | | 706. Design HashMap | Python | Easy | | 717. 1-bit and 2-bit Characters | Python | Easy | | 720. Longest Word in Dictionary | Python | Easy | | 724. Find Pivot Index | Python | Easy | | 728. Self Dividing Numbers | Python | Easy | | 733. Flood Fill | Python | Easy | | 743. Network Delay Time | Python | Medium | | 744. Find Smallest Letter Greater Than Target | Python | Easy | | 746. Min Cost Climbing Stairs | Python | Easy | | 748. Shortest Completing Word | Python | Easy | | 756. Pyramid Transition Matrix | Python | Medium | | 762. Prime Number of Set Bits in Binary Representation | Python | Easy | | 771. Jewels and Stones | Python | Easy | | 778. Swim in Rising Water | C(++) | Hard | | 784. Letter Case Permutation | Python | Easy | | 799. Champagne Tower | Python | Medium | | 801. Minimum Swaps To Make Sequences Increasing | Python | Medium | | 802. Find Eventual Safe States | Python | Medium | | 811. Subdomain Visit Count | Python | Easy | | 823. Binary Trees With Factors | Python | Medium | | 829. Consecutive Numbers Sum | Python | Hard | | 836. Rectangle Overlap | Python | Easy | | 841. Keys and Rooms | Python | Medium | | 857. Minimum Cost to Hire K Workers | Python | Hard | | 860. Lemonade Change | Python | Easy | | 871. Minimum Number of Refueling Stops | Python, C(++) | Hard | | 872. Leaf-Similar Trees | Python | Easy | | 883. Projection Area of 3D Shapes | Python | Easy | | 891. Sum of Subsequence Widths | Python | Hard | | 897. Increasing Order Search Tree | Python, JavaScript | Easy | | 905. Sort Array By Parity | Python | Easy | | 912. Sort an Array | JavaScript | Medium | | 930. Binary Subarrays With Sum | Python | Medium | | 931. Minimum Falling Path Sum | Python | Medium | | 958. Check Completeness of a Binary Tree | Python | Medium | | 965. Univalued Binary Tree | Python | Easy | | 987. Vertical Order Traversal of a Binary Tree | JavaScript | Medium | | 988. Smallest String Starting From Leaf | Python | Medium | | 1029. Two City Scheduling | Python | Easy | | 1046. Last Stone Weight | Python | Easy | | 1092. Shortest Common Supersequence | Python | Hard | | 1109. Corporate Flight Bookings | Python | Medium | | 1114. Print in Order | C(++) | Easy | | 1115. Print FooBar Alternately | C(++) | Medium | | 1129. Shortest Path with Alternating Colors | Python | Medium | | 1145. Binary Tree Coloring Game | Python | Medium | | 1160. Find Words That Can Be Formed by Characters | Python | Easy | | 1175. Prime Arrangements | Python | Easy | | 1202. Smallest String With Swaps | Python | Medium | | 1278. Palindrome Partitioning III | Python | Hard | | 1287. Element Appearing More Than 25% In Sorted Array | Python | Easy | | 1288. Remove Covered Intervals | Python | Medium | | 1289. Minimum Falling Path Sum II | Python | Hard | | 1290. Convert Binary Number in a Linked List to Integer | Python | Easy | | 1291. Sequential Digits | Python | Medium | | 1292. Maximum Side Length of a Square with Sum Less than or Equal to Threshold | Python | Medium | | 1293. Shortest Path in a Grid with Obstacles Elimination | Python | Hard | | 1295. Find Numbers with Even Number of Digits | C(++) | Easy | | 1296. Divide Array in Sets of K Consecutive Numbers | Python | Medium | | 1297. Maximum Number of Occurrences of a Substring | Python | Medium | | 1299. Replace Elements with Greatest Element on Right Side | Python | Easy | | 1300. Sum of Mutated Array Closest to Target | Python | Medium | | 1301. Number of Paths with Max Score | Python | Hard | | 1304. Find N Unique Integers Sum up to Zero | Python | Easy | | 1305. All Elements in Two Binary Search Trees | Python | Medium | | 1306. Jump Game III | Python | Medium | | 1312. Minimum Insertion Steps to Make a String Palindrome | Python, C(++) | Hard | | 1317. Convert Integer to the Sum of Two No-Zero Integers | Python | Easy | | 1319. Number of Operations to Make Network Connected | Python | Medium | | 1323. Maximum 69 Number | Python | Easy | | 1324. Print Words Vertically | Python | Medium | | 1325. Delete Leaves With a Given Value | Python | Medium | | 1326. Minimum Number of Taps to Open to Water a Garden | Python | Hard | | 1328. Break a Palindrome | C(++) | Medium | | 1329. Sort the Matrix Diagonally | Python | Medium | | 1330. Reverse Subarray To Maximize Array Value | Python | Hard | | 1331. Rank Transform of an Array | C(++) | Easy | | 1332. Remove Palindromic Subsequences | Python | Easy | | 1334. Find the City With the Smallest Number of Neighbors at a Threshold Distance | C(++) | Medium | | 1337. The K Weakest Rows in a Matrix | Python | Easy | | 1338. Reduce Array Size to The Half | Python | Medium | | 1339. Maximum Product of Splitted Binary Tree | Python | Medium | | 1356. Sort Integers by The Number of 1 Bits | Python | Easy |
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