| 1. Two Sum | Solution | Easy |
| 2. Add Two Numbers | Solution | Medium |
| 3. Longest Substring Without Repeating Characters | Solution | Medium |
| 4. Median of Two Sorted Arrays | Solution | Hard |
| 5. Longest Palindromic Substring | Solution | Medium |
| 9. Palindrome Number | Solution | Easy |
| 8. String to Integer (atoi) | Solution | Medium |
| 10. Regular Expression Matching | Solution | Hard |
| 11. Container With Most Water | Solution | Medium |
| 12. Integer to Roman | Solution | Medium |
| 13. Roman to Integer | Solution | Easy |
| 14. Longest Common Prefix | Solution | Easy |
| 15. 3Sum | Solution | Medium |
| 16. 3Sum Closest | Solution | Medium |
| 17. Letter Combinations of a Phone Number | Solution | Medium |
| 18. 4Sum | Solution | Medium |
| 19. Remove Nth Node From End of List | Solution | Medium |
| 20. Valid Parentheses | Solution | Easy |
| 21. Merge Two Sorted Lists | Solution | Easy |
| 22. Generate Parentheses | Solution | Medium |
| 23. Merge k Sorted Lists | Solution | Hard |
| 25. Reverse Nodes in k-Group | Solution | Hard |
| 26. Remove Duplicates from Sorted Array | Solution | Easy |
| 28. Implement strStr() | Solution | Easy |
| 29. Divide Two Integers | Solution | Easy |
| 31. Next Permutation | Solution | Medium |
| 32. Longest Valid Parentheses | Solution | Hard |
| 33. Search in Rotated Sorted Array | Solution | Medium |
| 34. Search for a Range | Solution | Medium |
| 35. Search Insert Position | Solution | Easy |
| 36. Valid Sudoku | Solution | Medium |
| 37. Sudoku Solver | Solution | Hard |
| 39. Combination Sum | Solution | Medium |
| 41. First Missing Positive | Solution | Hard |
| 42. Trapping Rain Water | Solution | Hard |
| 44. Wildcard Matching | Solution | Hard |
| 45. Jump Game II | Solution | Hard |
| 46. Permutations | Solution | Medium |
| 47. Permutations II | Solution | Medium |
| 48. Rotate Image | Solution | Medium |
| 49. Group Anagrams | Solution | Medium |
| 50. Pow(x, n) | Solution | Medium |
| 51. N-Queens | Solution | Hard |
| 52. N-Queens II | Solution | Hard |
| 53. Maximum Subarray | Solution | Easy |
| 54. Spiral Matrix | Solution | Medium |
| 55. Jump Game | Solution | Medium |
| 56. Merge Intervals | Solution | Medium |
| 57. Insert Interval | Solution | Hard |
| 59. Spiral Matrix II | Solution | Medium |
| 60. Permutation Sequence | Solution | Medium |
| 61. Rotate List | Solution | Medium |
| 62. Unique Paths | Solution | Medium |
| 63. Unique Paths II | Solution | Medium |
| 64. Minimum Path Sum | Solution | Medium |
| 65. Valid Number | Solution | Hard |
| 66. Plus One | Solution | Easy |
| 67. Add Binary | Solution | Easy |
| 68. Text Justification | Solution | Hard |
| 69. Sqrt(x) | Solution | Easy |
| 70. Climbing Stairs | Solution | Easy |
| 71. Simplify Path | Solution | Medium |
| 72. Edit Distance | Solution | Hard |
| 73. Set Matrix Zeroes | Solution | Medium |
| 74. Search a 2D Matrix | Solution | Medium |
| 75. Sort Colors | Solution | Medium |
| 76. Minimum Window Substring | Solution | Hard |
| 78. Subsets | Solution | Medium |
| 79. Word Search | Solution | Medium |
| 80. Remove Duplicates from Sorted Array II | Solution | Medium |
| 81. Search in Rotated Sorted Array II | Solution | Medium |
| 82. Remove Duplicates from Sorted List II | Solution | Medium |
| 83. Remove Duplicates from Sorted List | Solution | Easy |
| 84. Largest Rectangle in Histogram | Solution | Hard |
| 85. Maximal Rectangle | Solution | Hard |
| 86. Partition List | Solution | Medium |
| 88. Merge Sorted Array | Solution | Easy |
| 90. Subsets II | Solution | Medium |
| 91. Decode Ways | Solution | Medium |
| 92. Reverse Linked List II | Solution | Medium |
| 93. Restore IP Addresses | Solution | Medium |
| 94. Binary Tree Inorder Traversal | Solution | Medium |
| 95. Unique Binary Search Trees II | Solution | Medium |
| 96. Unique Binary Search Trees | Solution | Medium |
| 97. Interleaving String | Solution | Hard |
| 98. Validate Binary Search Tree | Solution | Medium |
| 100. Same Tree | Solution | Easy |
| 101. Symmetric Tree | Solution | Easy |
| 102. Binary Tree Level Order Traversal | Solution | Medium |
| 103. Binary Tree Zigzag Level Order Traversal | Solution | Medium |
| 104. Maximum Depth of Binary Tree | Solution | Easy |
| 105. Construct Binary Tree from Preorder and Inorder Traversal | Solution | Medium |
| 106. Construct Binary Tree from Inorder and Postorder Traversal | Solution | Medium |
| 107. Binary Tree Level Order Traversal II | Solution | Easy |
| 108. Convert Sorted Array to Binary Search Tree | Solution | Easy |
| 109. Convert Sorted List to Binary Search Tree | Solution | Medium |
| 110. Balanced Binary Tree | Solution | Easy |
| 111. Minimum Depth of Binary Tree | Solution | Easy |
| 112. Path Sum | Solution | Easy |
| 113. Path Sum II | Solution | Medium |
| 114. Flatten Binary Tree to Linked List | Solution | Medium |
| 116. Populating Next Right Pointers in Each Node | Solution | Medium |
| 117. Populating Next Right Pointers in Each Node II | Solution | Medium |
| 119. Pascal's Triangle II | Solution | Easy |
| 120. Triangle | Solution | Medium |
| 121. Best Time to Buy and Sell Stock | Solution | Easy |
| 122. Best Time to Buy and Sell Stock II | Solution | Easy |
| 123. Best Time to Buy and Sell Stock III | Solution | Hard |
| 124. Binary Tree Maximum Path Sum | Solution | Hard |
| 125. Valid Palindrome | Solution | Easy |
| 126. Word Ladder II | Solution | Hard |
| 127. Word Ladder | Solution | Medium |
| 128. Longest Consecutive Sequence | Solution | Hard |
| 129. Sum Root to Leaf Numbers | Solution | Medium |
| 130. Surrounded Regions | Solution | Medium |
| 131. Palindrome Partitioning | Solution | Medium |
| 133. Clone Graph | Solution | Medium |
| 136. Single Number | Solution | Easy |
| 137. Single Number II | Solution | Medium |
| 138. Copy List with Random Pointer | Solution | Medium |
| 139. Word Break | Solution | Medium |
| 140. Word Break II | Solution | Hard |
| 141. Linked List Cycle | Solution | Easy |
| 142. Linked List Cycle II | Solution | Easy |
| 143. Reorder List | Solution | Medium |
| 144. Binary Tree Preorder Traversal | Solution | Medium |
| 146. LRU Cache | Solution | Hard |
| 147. Insertion Sort List | Solution | Medium |
| 148. Sort List | Solution | Medium |
| 149. Max Points on a Line | Solution | Hard |
| 150. Evaluate Reverse Polish Notation | Solution | Medium |
| 151. Reverse Words in a String | Solution | Medium |
| 152. Maximum Product Subarray | Solution | Medium |
| 153. Find Minimum in Rotated Sorted Array | Solution | Medium |
| 154. Find Minimum in Rotated Sorted Array II | Solution | Hard |
| 155. Min Stack | Solution | Easy |
| 157. Read N Characters Given Read4 | Solution | Easy |
| 158. Read N Characters Given Read4 II - Call multiple times | Solution | Hard |
| 159. Longest Substring with At Most Two Distinct Characters | Solution | Hard |
| 160. Intersection of Two Linked Lists | Solution | Easy |
| 161. One Edit Distance | Solution | Medium |
| 162. Find Peak Element | Solution | Medium |
| 163. Missing Ranges | Solution | Medium |
| 165. Compare Version Numbers | Solution | Medium |
| 166. Fraction to Recurring Decimal | Solution | Medium |
| 167. Two Sum II - Input array is sorted | Solution | Easy |
| 169. Majority Element | Solution | Easy |
| 173. Binary Search Tree Iterator | Solution | Medium |
| 179. Largest Number | Solution | Medium |
| 186. Reverse Words in a String II | Solution | Easy |
| 187. Repeated DNA Sequences | Solution | Medium |
| 188. Best Time to Buy and Sell Stock IV | Solution | Hard |
| 189. Rotate Array | Solution | Easy |
| 198. House Robber | Solution | Easy |
| 199. Binary Tree Right Side View | Solution | Medium |
| 200. Number of Islands | Solution | Medium |
| 201. Bitwise AND of Numbers Range | Solution | Medium |
| 202. Happy Number | Solution | Easy |
| 203. Remove Linked List Elements | Solution | Easy |
| 204. Count Primes | Solution | Easy |
| 205. Isomorphic Strings | Solution | Easy |
| 206. Reverse Linked List | Solution | Easy |
| 207. Course Schedule | Solution | Medium |
| 208. Implement Trie (Prefix Tree) | Solution | Medium |
| 209. Minimum Size Subarray Sum | Solution | Medium |
| 210. Course Schedule II | Solution | Medium |
| 211. Add and Search Word - Data structure design | Solution | Medium |
| 212. Word Search II | Solution | Hard |
| 213. House Robber II | Solution | Medium |
| 214. Shortest Palindrome | Solution | Medium |
| 215. Kth Largest Element in an Array | Solution | Medium |
| 216. Combination Sum III | Solution | Medium |
| 217. Contains Duplicate | Solution | Easy |
| 218. The Skyline Problem | Solution | Hard |
| 219. Contains Duplicate II | Solution | Easy |
| 220. Contains Duplicate III | Solution | Medium |
| 221. Maximal Square | Solution | Medium |
| 223. Rectangle Area | Solution | Medium |
| 224. Basic Calculator | Solution | Hard |
| 225. Implement Stack using Queues | Solution | Easy |
| 226. Invert Binary Tree | Solution | Easy |
| 227. Basic Calculator II | Solution | Medium |
| 228. Summary Ranges | Solution | Medium |
| 230. Kth Smallest Element in a BST | Solution | Medium |
| 231. Power of Two | Solution | Easy |
| 232. Implement Queue using Stacks | Solution | Easy |
| 233. Number of Digit One | Solution | Hard |
| 234. Palindrome Linked List | Solution | Easy |
| 235. Lowest Common Ancestor of a Binary Search Tree | Solution | Easy |
| 236. Lowest Common Ancestor of a Binary Tree | Solution | Medium |
| 237. Delete Node in a Linked List | Solution | Easy |
| 238. Product of Array Except Self | Solution | Medium |
| 239. Sliding Window Maximum | Solution | Hard |
| 240. Search a 2D Matrix II | Solution | Medium |
| 241. Different Ways to Add Parentheses | Solution | Medium |
| 242. Valid Anagram | Solution | Easy |
| 243. Shortest Word Distance | Solution | Easy |
| 246. Strobogrammatic Number | Solution | Easy |
| 247. Strobogrammatic Number II | Solution | Medium |
| 249. Group Shifted Strings | Solution | Medium |
| 251. Flatten 2D Vector | Solution | Medium |
| 252. Meeting Rooms | Solution | Easy |
| 253. Meeting Rooms II | Solution | Medium |
| 255. Verify Preorder Sequence in Binary Search Tree | Solution | Medium |
| 256. Paint House | Solution | Easy |
| 257. Binary Tree Paths | Solution | Easy |
| 259. 3Sum Smaller | Solution | Medium |
| 261. Graph Valid Tree | Solution | Medium |
| 263. Ugly Number | Solution | Easy |
| 264. Ugly Number II | Solution | Medium |
| 265. Paint House II | Solution | Hard |
| 267. Palindrome Permutation II | Solution | Medium |
| 268. Missing Number | Solution | Easy |
| 269. Alien Dictionary | Solution | Hard |
| 270. Closest Binary Search Tree Value | Solution | Easy |
| 271. Encode and Decode Strings | Solution | Medium |
| 272. Closest Binary Search Tree Value II | Solution | Medium |
| 273. Integer to English Words | Solution | Hard |
| 274. H-Index | Solution | Medium |
| 276. Paint Fence | Solution | Easy |
| 277. Find the Celebrity | Solution | Medium |
| 278. First Bad Version | Solution | Easy |
| 279. Perfect Squares | Solution | Medium |
| 280. Wiggle Sort | Solution | Medium |
| 281. Zigzag Iterator | Solution | Medium |
| 282. Expression Add Operators | Solution | Hard |
| 283. Move Zeroes | Solution | Easy |
| 284. Peeking Iterator | Solution | Medium |
| 285. Inorder Successor in BST | Solution | Medium |
| 286. Walls and Gates | Solution | Medium |
| 287. Find the Duplicate Number | Solution | Medium |
| 288. Unique Word Abbreviation | Solution | Medium |
| 289. Game of Life | Solution | Medium |
| 290. Word Pattern | Solution | Easy |
| 291. Word Pattern II | Solution | Hard |
| 293. Flip Game | Solution | Easy |
| 295. Find Median from Data Stream | Solution | Hard |
| 296. Best Meeting Point | Solution | Hard |
| 297. Serialize and Deserialize Binary Tree | Solution | Hard |
| 298. Binary Tree Longest Consecutive Sequence | Solution | Medium |
| 299. Bulls and Cows | Solution | Medium |
| 300. Longest Increasing Subsequence | Solution | Medium |
| 301. Remove Invalid Parentheses | Solution | Hard |
| 303. Range Sum Query - Immutable | Solution | Easy |
| 304. Range Sum Query 2D - Immutable | Solution | Medium |
| 305. Number of Islands II | Solution | Hard |
| 307. Range Sum Query - Mutable | Solution | Medium |
| 308. Range Sum Query 2D - Mutable | Solution | Hard |
| 309. Best Time to Buy and Sell Stock with Cooldown | Solution | Medium |
| 310. Minimum Height Trees | Solution | Medium |
| 311. Sparse Matrix Multiplication | Solution | Medium |
| 312. Burst Balloons | Solution | Hard |
| 313. Super Ugly Number | Solution | Medium |
| 314. Binary Tree Vertical Order Traversal | Solution | Medium |
| 315. Count of Smaller Numbers After Self | Solution | Hard |
| 317. Shortest Distance from All Buildings | Solution | Hard |
| 318. Maximum Product of Word Lengths | Solution | Medium |
| 320. Generalized Abbreviation | Solution | Medium |
| 322. Coin Change | Solution | Medium |
| 323. Number of Connected Components in an Undirected Graph | Solution | Medium |
| 324. Wiggle Sort II | Solution | Medium |
| 325. Maximum Size Subarray Sum Equals k | Solution | Medium |
| 327. Count of Range Sum | Solution | Hard |
| 328. Odd Even Linked List | Solution | Medium |
| 332. Reconstruct Itinerary | Solution | Medium |
| 333. Largest BST Subtree | Solution | Medium |
| 334. Increasing Triplet Subsequence | Solution | Medium |
| 336. Palindrome Pairs | Solution | Hard |
| 337. House Robber III | Solution | Medium |
| 338. Counting Bits | Solution | Medium |
| 339. Nested List Weight Sum | Solution | Easy |
| 340. Longest Substring with At Most K Distinct Characters | Solution | Hard |
| 341. Flatten Nested List Iterator | Solution | Medium |
| 343. Integer Break | Solution | Medium |
| 344. Reverse String | Solution | Easy |
| 345. Reverse Vowels of a String | Solution | Easy |
| 346. Moving Average from Data Stream | Solution | Easy |
| 347. Top K Frequent Elements | Solution | Medium |
| 348. Design Tic-Tac-Toe | Solution | Medium |
| 349. Intersection of Two Arrays | Solution | Easy |
| 350. Intersection of Two Arrays II | Solution | Easy |
| 351. Android Unlock Patterns | Solution | Medium |
| 352. Data Stream as Disjoint Intervals | Solution | Hard |
| 353. Design Snake Game | Solution | Medium |
| 354. Russian Doll Envelopes | Solution | Hard |
| 355. Design Twitter | Solution | Medium |
| 357. Count Numbers with Unique Digits | Solution | Medium |
| 358. Rearrange String k Distance Apart | Solution | Hard |
| 359. Logger Rate Limiter | Solution | Easy |
| 360. Sort Transformed Array | Solution | Medium |
| 361. Bomb Enemy | Solution | Medium |
| 362. Design Hit Counter | Solution | Medium |
| 363. Max Sum of Rectangle No Larger Than K | Solution | Hard |
| 365. Water and Jug Problem | Solution | Medium |
| 368. Largest Divisible Subset | Solution | Medium |
| 369. Plus One Linked List | Solution | Medium |
| 370. Range Addition | Solution | Medium |
| 373. Find K Pairs with Smallest Sums | Solution | Medium |
| 375. Guess Number Higher or Lower II | Solution | Medium |
| 377. Combination Sum IV | Solution | Medium |
| 378. Kth Smallest Element in a Sorted Matrix | Solution | Medium |
| 380. Insert Delete GetRandom O(1) | Solution | Medium |
| 382. Linked List Random Node | Solution | Medium |
| 383. Ransom Note | Solution | Easy |
| 384. Shuffle an Array | Solution | Medium |
| 386. Lexicographical Numbers | Solution | Medium |
| 387. First Unique Character in a String | Solution | Easy |
| 388. Longest Absolute File Path | Solution | Medium |
| 392. Is Subsequence | Solution | Medium |
| 393. UTF-8 Validation | Solution | Medium |
| 394. Decode String | Solution | Medium |
| 396. Rotate Function | Solution | Medium |
| 399. Evaluate Division | Solution | Medium |
| 403. Frog Jump | Solution | Hard |
| 405. Convert a Number to Hexadecimal | Solution | Easy |
| 406. Queue Reconstruction by Height | Solution | Medium |
| 407. Trapping Rain Water II | Solution | Medium |
| 408. Valid Word Abbreviation | Solution | Easy |
| 409. Longest Palindrome | Solution | Easy |
| 410. Split Array Largest Sum | Solution | Hard |
| 412. Fizz Buzz | Solution | Easy |
| 414. Third Maximum Number | Solution | Easy |
| 415. Add Strings | Solution | Easy |
| 416. Partition Equal Subset Sum | Solution | Medium |
| 417. Pacific Atlantic Water Flow | Solution | Medium |
| 418. Sentence Screen Fitting | Solution | Medium |
| 421. Maximum XOR of Two Numbers in an Array | Solution | Medium |
| 423. Reconstruct Original Digits from English | Solution | Medium |
| 424. Longest Repeating Character Replacement | Solution | Medium |
| 425. Word Squares | Solution | Hard |
| 427. Construct Quad Tree | Solution | Easy |
| 429. N-ary Tree Level Order Traversal | Solution | Easy |
| 432. All O`one Data Structure | Solution | Hard |
| 433. Minimum Genetic Mutation | Solution | Medium |
| 435. Non-overlapping Intervals | Solution | Medium |
| 437. Path Sum III | Solution | Easy |
| 438. Find All Anagrams in a String | Solution | Easy |
| 443. String Compression | Solution | Easy |
| 445. Add Two Numbers II | Solution | Medium |
| 448. Find All Numbers Disappeared in an Array | Solution | Easy |
| 449. Serialize and Deserialize BST | Solution | Medium |
| 450. Delete Node in a BST | Solution | Medium |
| 454. 4Sum II | Solution | Medium |
| 451. Sort Characters By Frequency | Solution | Medium |
| 459. Repeated Substring Pattern | Solution | Easy |
| 460. LFU Cache | Solution | Hard |
| 462. Minimum Moves to Equal Array Elements II | Solution | Medium |
| 463. Island Perimeter | Solution | Easy |
| 464. Can I Win | Solution | Medium |
| 465. Optimal Account Balancing | Solution | Hard |
| 472. Concatenated Words | Solution | Hard |
| 473. Matchsticks to Square | Solution | Medium |
| 474. Ones and Zeroes | Solution | Medium |
| 477. Total Hamming Distance | Solution | Medium |
| 480. Sliding Window Median | Solution | Hard |
| 481. Magical String | Solution | Medium |
| 482. License Key Formatting | Solution | Easy |
| 485. Max Consecutive Ones | Solution | Easy |
| 486. Predict the Winner | Solution | Medium |
| 487. Max Consecutive Ones II | Solution | Medium |
| 490. The Maze | Solution | Medium |
| 491. Increasing Subsequences | Solution | Medium |
| 494. Target Sum | Solution | Medium |
| 496. Next Greater Element I | Solution | Easy |
| 498. Diagonal Traverse | Solution | Medium |
| 499. The Maze III | Solution | Hard |
| 503. Next Greater Element II | Solution | Medium |
| 505. The Maze II | Solution | Hard |
| 508. Most Frequent Subtree Sum | Solution | Medium |
| 513. Find Bottom Left Tree Value | Solution | Medium |
| 515. Find Largest Value in Each Tree Row | Solution | Medium |
| 516. Longest Palindromic Subsequence | Solution | Medium |
| 518. Coin Change 2 | Solution | Medium |
| 519. Random Flip Matrix | Solution | Medium |
| 523. Continuous Subarray Sum | Solution | Medium |
| 525. Contiguous Array | Solution | Medium |
| 527. Word Abbreviation | Solution | Hard |
| 529. Minesweeper | Solution | Medium |
| 530. Minimum Absolute Difference in BST | Solution | Easy |
| 531. Lonely Pixel I | Solution | Medium |
| 535. Encode and Decode TinyURL | Solution | Medium |
| 536. Construct Binary Tree from String | Solution | Medium |
| 538. Convert BST to Greater Tree | Solution | Easy |
| 540. Single Element in a Sorted Array | Solution | Medium |
| 541. Reverse String II | Solution | Easy |
| 542. 01 Matrix | Solution | Medium |
| 543. Diameter of Binary Tree | Solution | Easy |
| 544. Output Contest Matches | Solution | Medium |
| 545. Boundary of Binary Tree | Solution | Medium |
| 547. Friend Circles | Solution | Medium |
| 554. Brick Wall | Solution | Medium |
| 556. Next Greater Element III | Solution | Medium |
| 557. Reverse Words in a String III | Solution | Easy |
| 558. Quad Tree Intersection | Solution | Easy |
| 560. Subarray Sum Equals K | Solution | Medium |
| 567. Permutation in String | Solution | Easy |
| 568. Maximum Vacation Days | Solution | Hard |
| 572. Subtree of Another Tree | Solution | Easy |
| 582. Kill Process | Solution | Medium |
| 588. Design In-Memory File System | Solution | Hard |
| 590. N-ary Tree Postorder Traversal | Solution | Easy |
| 594. Longest Harmonious Subsequence | Solution | Easy |
| 604. Design Compressed String Iterator | Solution | Easy |
| 611. Valid Triangle Number | Solution | Medium |
| 616. Add Bold Tag in String | Solution | Medium |
| 621. Task Scheduler | Solution | Medium |
| 622. Design Circular Queue | Solution | Medium |
| 623. Add One Row to Tree | Solution | Medium |
| 628. Maximum Product of Three Numbers | Solution | Easy |
| 632. Smallest Range | Solution | Hard |
| 633. Sum of Square Numbers | Solution | Easy |
| 635. Design Log Storage System | Solution | Hard |
| 636. Exclusive Time of Functions | Solution | Medium |
| 637. Average of Levels in Binary Tree | Solution | Easy |
| 639. Decode Ways II | Solution | Hard |
| 640. Solve the Equation | Solution | Medium |
| 641. Design Circular Deque | Solution | Medium |
| 642. Design Search Autocomplete System | Solution | Hard |
| 643. Maximum Average Subarray I | Solution | Easy |
| 646. Maximum Length of Pair Chain | Solution | Medium |
| 647. Palindromic Substrings | Solution | Medium |
| 648. Replace Words | Solution | Medium |
| 652. Find Duplicate Subtrees | Solution | Medium |
| 653. Two Sum IV - Input is a BST | Solution | Easy |
| 654. Maximum Binary Tree | Solution | Medium |
| 657. Judge Route Circle | Solution | Easy |
| 658. Find K Closest Elements | Solution | Medium |
| 659. Split Array into Consecutive Subsequences | Solution | Medium |
| 661. Image Smoother | Solution | Easy |
| 662. Maximum Width of Binary Tree | Solution | Medium |
| 663. Equal Tree Partition | Solution | Medium |
| 665. Non-decreasing Array | Solution | Easy |
| 669. Trim a Binary Search Tree | Solution | Easy |
| 671. Second Minimum Node In a Binary Tree | Solution | Easy |
| 673. Number of Longest Increasing Subsequence | Solution | Medium |
| 674. Longest Continuous Increasing Subsequence | Solution | Easy |
| 675. Cut Off Trees for Golf Event | Solution | Hard |
| 676. Implement Magic Dictionary | Solution | Medium |
| 677. Map Sum Pairs | Solution | Medium |
| 678. Valid Parenthesis String | Solution | Medium |
| 680. Valid Palindrome II | Solution | Easy |
| 681. Next Closest Time | Solution | Medium |
| 682. Baseball Game | Solution | Easy |
| 683. K Empty Slots | Solution | Hard |
| 684. Redundant Connection | Solution | Medium |
| 685. Redundant Connection II | Solution | Hard |
| 686. Repeated String Match | Solution | Easy |
| 687. Longest Univalue Path | Solution | Easy |
| 689. Maximum Sum of 3 Non-Overlapping Subarrays | Solution | Hard |
| 692. Top K Frequent Words | Solution | Medium |
| 695. Max Area of Island | Solution | Medium |
| 698. Partition to K Equal Sum Subsets | Solution | Medium |
| 702. Search in a Sorted Array of Unknown Size | Solution | Medium |
| 705. Design HashSet | Solution | Easy |
| 706. Design HashMap | Solution | Easy |
| 707. Design Linked List | Solution | Easy |
| 709. To Lower Case | Solution | Easy |
| 712. Minimum ASCII Delete Sum for Two Strings | Solution | Medium |
| 713. Subarray Product Less Than K | Solution | Medium |
| 714. Best Time to Buy and Sell Stock with Transaction Fee | Solution | Medium |
| 715. Range Module | Solution | Hard |
| 716. Max Stack | Solution | Hard |
| 718. Maximum Length of Repeated Subarray | Solution | Medium |
| 719. Find K-th Smallest Pair Distance | Solution | Hard |
| 720. Longest Word in Dictionary | Solution | Easy |
| 721. Accounts Merge | Solution | Medium |
| 727. Minimum Window Subsequence | Solution | Hard |
| 729. My Calendar I | Solution | Medium |
| 731. My Calendar II | Solution | Medium |
| 734. Sentence Similarity | Solution | Easy |
| 737. Sentence Similarity II | Solution | Medium |
| 738. Monotone Increasing Digits | Solution | Medium |
| 739. Daily Temperatures | Solution | Medium |
| 740. Delete and Earn | Solution | Medium |
| 746. Min Cost Climbing Stairs | Solution | Easy |
| 748. Shortest Completing Word | Solution | Medium |
| 750. Number Of Corner Rectangles | Solution | Medium |
| 752. Open the Lock | Solution | Medium |
| 759. Employee Free Time | Solution | Hard |
| 760. Find Anagram Mappings | Solution | Easy |
| 763. Partition Labels | Solution | Medium |
| 765. Couples Holding Hands | Solution | Hard |
| 767. Reorganize String | Solution | Medium |
| 768. Max Chunks To Make Sorted II | Solution | Hard |
| 769. Max Chunks To Make Sorted | Solution | Medium |
| 771. Jewels and Stones | Solution | Easy |
| 777. Swap Adjacent in LR String | Solution | Medium |
| 779. K-th Symbol in Grammar | Solution | Medium |
| 785. Is Graph Bipartite? | Solution | Medium |
| 787. Cheapest Flights Within K Stops | Solution | Medium |
| 790. Domino and Tromino Tiling | Solution | Medium |
| 792. Number of Matching Subsequences | Solution | Medium |
| 797. All Paths From Source to Target | Solution | Medium |
| 783. Minimum Distance Between BST Nodes | Solution | Easy |
| 802. Find Eventual Safe States | Solution | Medium |
| 803. Bricks Falling When Hit | Solution | Hard |
| 804. Unique Morse Code Words | Solution | Easy |
| 807. Max Increase to Keep City Skyline | Solution | Medium |
| 819. Most Common Word | Solution | Easy |
| 826. Most Profit Assigning Work | Solution | Medium |
| 832. Flipping an Image | Solution | Easy |
| 836. Rectangle Overlap | Solution | Easy |
| 841. Keys and Rooms | Solution | Medium |
| 842. Split Array into Fibonacci Sequence | Solution | Medium |
| 843. Guess the Word | Solution | Hard |
| 844. Backspace String Compare | Solution | Easy |
| 845. Longest Mountain in Array | Solution | Medium |
| 846. Hand of Straights | Solution | Medium |
| 849. Maximize Distance to Closest Person | Solution | Easy |
| 850. Rectangle Area II | Solution | Hard |
| 855. Exam Room | Solution | Medium |
| 859. Buddy Strings | Solution | Easy |
| 860. Lemonade Change | Solution | Easy |
| 862. Shortest Subarray with Sum at Least K | Solution | Hard |
| 863. All Nodes Distance K in Binary Tree | Solution | Medium |
| 864. Shortest Path to Get All Keys | Solution | Hard |
| 873. Length of Longest Fibonacci Subsequence | Solution | Medium |
| 875. Koko Eating Bananas | Solution | Easy |
| 876. Middle of the Linked List | Solution | Easy |
| 877. Stone Game | Solution | Medium |
| 879. Profitable Schemes | Solution | Hard |
| 884. Decoded String at Index | Solution | Medium |
| 885. Boats to Save People | Solution | Medium |
| 886. Possible Bipartition | Solution | Medium |
| 887. Projection Area of 3D Shapes | Solution | Easy |
| 890. Find and Replace Pattern | Solution | Medium |
| 895. Maximum Frequency Stack | Solution | Hard |
| Convert Binary Search Tree to Sorted Doubly Linked List | Solution | - |
| HighestPopulationYear | Solution | - |
| Insert into a Cyclic Sorted List | Solution | - |
| Robot Room Cleaner | Solution | - |
| AsyncJobMonitor | Solution | - |
| Bench | Solution | - |
| FindCenterOfMassInA2DArray | Solution | - |
| OneEditDistance | Solution | - |
| CollatzConjecture | Solution | - |
| Subsequence | Solution | - |
| TreeToForestByErasingNodes | Solution | - |
| KMP | Solution | - |