| 1. Two Sum (Solution) |
2. Add Two Numbers (Solution) |
3. Longest Substring Without Repeating Characters (Solution) |
| 6. ZigZag Conversion (Solution) |
7. Reverse Integer (Solution) |
8. String to Integer (atoi) (Solution) |
| 9. Palindrome Number (Solution) |
10. Regular Expression Matching (Solution) |
11. Container With Most Water (Solution) |
| 12. Integer to Roman (Solution) |
13. Roman to Integer (Solution) |
14. Longest Common Prefix (Solution) |
| 15. 3Sum (Solution) |
16. 3Sum Closest (Solution) |
17. Letter Combinations of a Phone Number (Solution) |
| 18. 4Sum (Solution) |
19. Remove Nth Node From End of List (Solution) |
20. Valid Parentheses (Solution) |
| 21. Merge Two Sorted Lists (Solution) |
22. Generate Parentheses (Solution) |
23. Merge k Sorted Lists (Solution) |
| 24. Swap Nodes in Pairs (Solution) |
26. Remove Duplicates from Sorted Array (Solution) |
27. Remove Element (Solution) |
| 28. Implement strStr() (Solution) |
29. Divide Two Integers (Solution) |
31. Next Permutation (Solution) |
| 33. Search in Rotated Sorted Array (Solution) |
34. Search for a Range (Solution) |
35. Search Insert Position (Solution) |
| 36. Valid Sudoku (Solution) |
37. Sudoku Solver (Solution) |
38. Count and Say (Solution) |
| 39. Combination Sum (Solution) |
40. Combination Sum II (Solution) |
42. Trapping Rain Water (Solution) |
| 43. Multiply Strings (Solution) |
44. Wildcard Matching (Solution) |
46. Permutations (Solution) |
| 47. Permutations II (Solution) |
48. Rotate Image (Solution) |
49. Group Anagrams (Solution) |
| 50. Pow(x, n) (Solution) |
51. N-Queens (Solution) |
52. N-Queens II (Solution) |
| 53. Maximum Subarray (Solution) |
54. Spiral Matrix (Solution) |
55. Jump Game (Solution) |
| 56. Merge Intervals (Solution) |
58. Length of Last Word (Solution) |
59. Spiral Matrix II (Solution) |
| 60. Permutation Sequence (Solution) |
61. Rotate List (Solution) |
62. Unique Paths (Solution) |
| 63. Unique Paths II (Solution) |
64. Minimum Path Sum (Solution) |
66. Plus One (Solution) |
| 67. Add Binary (Solution) |
69. Sqrt(x) (Solution) |
70. Climbing Stairs (Solution) |
| 71. Simplify Path (Solution) |
73. Set Matrix Zeroes (Solution) |
74. Search a 2D Matrix (Solution) |
| 75. Sort Colors (Solution) |
76. Minimum Window Substring (Solution) |
77. Combinations (Solution) |
| 78. Subsets (Solution) |
79. Word Search (Solution) |
80. Remove Duplicates from Sorted Array II (Solution) |
| 82. Remove Duplicates from Sorted List II (Solution) |
83. Remove Duplicates from Sorted List (Solution) |
86. Partition List (Solution) |
| 88. Merge Sorted Array (Solution) |
89. Gray Code (Solution) |
90. Subsets II (Solution) |
| 91. Decode Ways (Solution) |
92. Reverse Linked List II (Solution) |
93. Restore IP Addresses (Solution) |
| 94. Binary Tree Inorder Traversal (Solution) |
95. Unique Binary Search Trees II (Solution) |
96. Unique Binary Search Trees (Solution) |
| 98. Validate Binary Search Tree (Solution) |
100. Same Tree (Solution) |
101. Symmetric Tree (Solution) |
| 102. Binary Tree Level Order Traversal (Solution) |
103. Binary Tree Zigzag Level Order Traversal (Solution) |
104. Maximum Depth of Binary Tree (Solution) |
| 105. Construct Binary Tree from Preorder and Inorder Traversal (Solution) |
106. Construct Binary Tree from Inorder and Postorder Traversal (Solution) |
107. Binary Tree Level Order Traversal II (Solution) |
| 108. Convert Sorted Array to Binary Search Tree (Solution) |
109. Convert Sorted List to Binary Search Tree (Solution) |
110. Balanced Binary Tree (Solution) |
| 111. Minimum Depth of Binary Tree (Solution) |
112. Path Sum (Solution) |
113. Path Sum II (Solution) |
| 114. Flatten Binary Tree to Linked List (Solution) |
116. Populating Next Right Pointers in Each Node (Solution) |
117. Populating Next Right Pointers in Each Node II (Solution) |
| 118. Pascal’s Triangle (Solution) |
119. Pascal’s Triangle II (Solution) |
120. Triangle (Solution) |
| 121. Best Time to Buy and Sell Stock (Solution) |
122. Best Time to Buy and Sell Stock II (Solution) |
124. Binary Tree Maximum Path Sum (Solution) |
| 125. Valid Palindrome (Solution) |
126. Word Ladder II (Solution) |
127. Word Ladder (Solution) |
| 129. Sum Root to Leaf Numbers (Solution) |
130. Surrounded Regions (Solution) |
131. Palindrome Partitioning (Solution) |
| 133. Clone Graph (Solution) |
134. Gas Station (Solution) |
136. Single Number (Solution) |
| 138. Copy List with Random Pointer (Solution) |
139. Word Break (Solution) |
140. Word Break II (Solution) |
| 141. Linked List Cycle (Solution) |
142. Linked List Cycle II (Solution) |
143. Reorder List (Solution) |
| 144. Binary Tree Preorder Traversal (Solution) |
145. Binary Tree Postorder Traversal (Solution) |
146. LRU Cache (Solution) |
| 147. Insertion Sort List (Solution) |
150. Evaluate Reverse Polish Notation (Solution) |
151. Reverse Words in a String (Solution) |
| 152. Maximum Product Subarray (Solution) |
153. Find Minimum in Rotated Sorted Array (Solution) |
155. Min Stack (Solution) |
| 156. Binary Tree Upside Down (Solution) |
160. Intersection of Two Linked Lists (Solution) |
161. One Edit Distance (Solution) |
| 162. Find Peak Element (Solution) |
163. Missing Ranges (Solution) |
165. Compare Version Numbers (Solution) |
| 166. Fraction to Recurring Decimal (Solution) |
167. Two Sum II - Input array is sorted (Solution) |
168. Excel Sheet Column Title (Solution) |
| 169. Majority Element (Solution) |
171. Excel Sheet Column Number (Solution) |
172. Factorial Trailing Zeroes (Solution) |
| 173. Binary Search Tree Iterator (Solution) |
179. Largest Number (Solution) |
186. Reverse Words in a String II (Solution) |
| 187. Repeated DNA Sequences (Solution) |
189. Rotate Array (Solution) |
190. Reverse Bits (Solution) |
| 191. Number of 1 Bits (Solution) |
198. House Robber (Solution) |
199. Binary Tree Right Side View (Solution) |
| 200. Number of Islands (Solution) |
201. Bitwise AND of Numbers Range (Solution) |
202. Happy Number (Solution) |
| 203. Remove Linked List Elements (Solution) |
204. Count Primes (Solution) |
205. Isomorphic Strings (Solution) |
| 206. Reverse Linked List (Solution) |
207. Course Schedule (Solution) |
208. Implement Trie (Prefix Tree) (Solution) |
| 209. Minimum Size Subarray Sum (Solution) |
210. Course Schedule II (Solution) |
211. Add and Search Word - Data structure design (Solution) |
| 213. House Robber II (Solution) |
215. Kth Largest Element in an Array (Solution) |
216. Combination Sum III (Solution) |
| 217. Contains Duplicate (Solution) |
219. Contains Duplicate II (Solution) |
220. Contains Duplicate III (Solution) |
| 221. Maximal Square (Solution) |
222. Count Complete Tree Nodes (Solution) |
223. Rectangle Area (Solution) |
| 225. Implement Stack using Queues (Solution) |
226. Invert Binary Tree (Solution) |
227. Basic Calculator II (Solution) |
| 228. Summary Ranges (Solution) |
229. Majority Element II (Solution) |
230. Kth Smallest Element in a BST (Solution) |
| 231. Power of Two (Solution) |
232. Implement Queue using Stacks (Solution) |
234. Palindrome Linked List (Solution) |
| 235. Lowest Common Ancestor of a Binary Search Tree (Solution) |
236. Lowest Common Ancestor of a Binary Tree (Solution) |
237. Delete Node in a Linked List (Solution) |
| 238. Product of Array Except Self (Solution) |
239. Sliding Window Maximum (Solution) |
240. Search a 2D Matrix II (Solution) |
| 241. Different Ways to Add Parentheses (Solution) |
242. Valid Anagram (Solution) |
243. Shortest Word Distance (Solution) |
| 244. Shortest Word Distance II (Solution) |
245. Shortest Word Distance III (Solution) |
247. Strobogrammatic Number II (Solution) |
| 249. Group Shifted Strings (Solution) |
250. Count Univalue Subtrees (Solution) |
251. Flatten 2D Vector (Solution) |
| 253. Meeting Rooms II (Solution) |
254. Factor Combinations (Solution) |
255. Verify Preorder Sequence in Binary Search Tree (Solution) |
| 257. Binary Tree Paths (Solution) |
258. Add Digits (Solution) |
259. 3Sum Smaller (Solution) |
| 260. Single Number III (Solution) |
261. Graph Valid Tree (Solution) |
263. Ugly Number (Solution) |
| 264. Ugly Number II (Solution) |
266. Palindrome Permutation (Solution) |
267. Palindrome Permutation II (Solution) |
| 268. Missing Number (Solution) |
271. Encode and Decode Strings (Solution) |
274. H-Index (Solution) |
| 275. H-Index II (Solution) |
277. Find the Celebrity (Solution) |
278. First Bad Version (Solution) |
| 279. Perfect Squares (Solution) |
280. Wiggle Sort (Solution) |
281. Zigzag Iterator (Solution) |
| 283. Move Zeroes (Solution) |
284. Peeking Iterator (Solution) |
285. Inorder Successor in BST (Solution) |
| 286. Walls and Gates (Solution) |
287. Find the Duplicate Number (Solution) |
288. Unique Word Abbreviation (Solution) |
| 289. Game of Life (Solution) |
290. Word Pattern (Solution) |
291. Word Pattern II (Solution) |
| 292. Nim Game (Solution) |
294. Flip Game II (Solution) |
295. Find Median from Data Stream (Solution) |
| 297. Serialize and Deserialize Binary Tree (Solution) |
298. Binary Tree Longest Consecutive Sequence (Solution) |
299. Bulls and Cows (Solution) |
| 300. Longest Increasing Subsequence (Solution) |
303. Range Sum Query - Immutable (Solution) |
304. Range Sum Query 2D - Immutable (Solution) |
| 306. Additive Number (Solution) |
310. Minimum Height Trees (Solution) |
311. Sparse Matrix Multiplication (Solution) |
| 313. Super Ugly Number (Solution) |
314. Binary Tree Vertical Order Traversal (Solution) |
318. Maximum Product of Word Lengths (Solution) |
| 319. Bulb Switcher (Solution) |
320. Generalized Abbreviation (Solution) |
322. Coin Change (Solution) |
| 323. Number of Connected Components in an Undirected Graph (Solution) |
325. Maximum Size Subarray Sum Equals k (Solution) |
326. Power of Three (Solution) |
| 328. Odd Even Linked List (Solution) |
331. Verify Preorder Serialization of a Binary Tree (Solution) |
332. Reconstruct Itinerary (Solution) |
| 333. Largest BST Subtree (Solution) |
334. Increasing Triplet Subsequence (Solution) |
337. House Robber III (Solution) |
| 338. Counting Bits (Solution) |
341. Flatten Nested List Iterator (Solution) |
342. Power of Four (Solution) |
| 343. Integer Break (Solution) |
344. Reverse String (Solution) |
345. Reverse Vowels of a String (Solution) |
| 346. Moving Average from Data Stream (Solution) |
347. Top K Frequent Elements (Solution) |
349. Intersection of Two Arrays (Solution) |
| 350. Intersection of Two Arrays II (Solution) |
351. Android Unlock Patterns (Solution) |
353. Design Snake Game (Solution) |
| 356. Line Reflection (Solution) |
357. Count Numbers with Unique Digits (Solution) |
360. Sort Transformed Array (Solution) |
| 361. Bomb Enemy (Solution) |
362. Design Hit Counter (Solution) |
364. Nested List Weight Sum II (Solution) |
| 365. Water and Jug Problem (Solution) |
366. Find Leaves of Binary Tree (Solution) |
367. Valid Perfect Square (Solution) |
| 368. Largest Divisible Subset (Solution) |
369. Plus One Linked List (Solution) |
370. Range Addition (Solution) |
| 371. Sum of Two Integers (Solution) |
372. Super Pow (Solution) |
373. Find K Pairs with Smallest Sums (Solution) |
| 374. Guess Number Higher or Lower (Solution) |
376. Wiggle Subsequence (Solution) |
377. Combination Sum IV (Solution) |
| 378. Kth Smallest Element in a Sorted Matrix (Solution) |
379. Design Phone Directory (Solution) |
380. Insert Delete GetRandom O(1) (Solution) |
| 383. Ransom Note (Solution) |
384. Shuffle an Array (Solution) |
385. Mini Parser (Solution) |
| 386. Lexicographical Numbers (Solution) |
387. First Unique Character in a String (Solution) |
388. Longest Absolute File Path (Solution) |
| 389. Find the Difference (Solution) |
390. Elimination Game (Solution) |
392. Is Subsequence (Solution) |
| 393. UTF-8 Validation (Solution) |
394. Decode String (Solution) |
395. Longest Substring with At Least K Repeating Characters (Solution) |
| 396. Rotate Function (Solution) |
397. Integer Replacement (Solution) |
398. Random Pick Index (Solution) |
| 399. Evaluate Division (Solution) |
401. Binary Watch (Solution) |
402. Remove K Digits (Solution) |
| 404. Sum of Left Leaves (Solution) |
405. Convert a Number to Hexadecimal (Solution) |
406. Queue Reconstruction by Height (Solution) |
| 409. Longest Palindrome (Solution) |
412. Fizz Buzz (Solution) |
413. Arithmetic Slices (Solution) |
| 414. Third Maximum Number (Solution) |
415. Add Strings (Solution) |
416. Partition Equal Subset Sum (Solution) |
| 417. Pacific Atlantic Water Flow (Solution) |
418. Sentence Screen Fitting (Solution) |
419. Battleships in a Board (Solution) |
| 421. Maximum XOR of Two Numbers in an Array (Solution) |
423. Reconstruct Original Digits from English (Solution) |
424. Longest Repeating Character Replacement (Solution) |
| 432. All O`one Data Structure (Solution) |
434. Number of Segments in a String (Solution) |
435. Non-overlapping Intervals (Solution) |
| 436. Find Right Interval (Solution) |
437. Path Sum III (Solution) |
438. Find All Anagrams in a String (Solution) |
| 439. Ternary Expression Parser (Solution) |
441. Arranging Coins (Solution) |
442. Find All Duplicates in an Array (Solution) |
| 445. Add Two Numbers II (Solution) |
448. Find All Numbers Disappeared in an Array (Solution) |
449. Serialize and Deserialize BST (Solution) |
| 450. Delete Node in a BST (Solution) |
451. Sort Characters By Frequency (Solution) |
452. Minimum Number of Arrows to Burst Balloons (Solution) |
| 453. Minimum Moves to Equal Array Elements (Solution) |
454. 4Sum II (Solution) |
455. Assign Cookies (Solution) |
| 456. 132 Pattern (Solution) |
459. Repeated Substring Pattern (Solution) |
460. LFU Cache (Solution) |
| 461. Hamming Distance (Solution) |
462. Minimum Moves to Equal Array Elements II (Solution) |
463. Island Perimeter (Solution) |
| 467. Unique Substrings in Wraparound String (Solution) |
468. Validate IP Address (Solution) |
469. Convex Polygon (Solution) |
| 473. Matchsticks to Square (Solution) |
474. Ones and Zeroes (Solution) |
475. Heaters (Solution) |
| 476. Number Complement (Solution) |
477. Total Hamming Distance (Solution) |
481. Magical String (Solution) |
| 484. Find Permutation (Solution) |
485. Max Consecutive Ones (Solution) |
486. Predict the Winner (Solution) |
| 487. Max Consecutive Ones II (Solution) |
490. The Maze (Solution) |
491. Increasing Subsequences (Solution) |
| 492. Construct the Rectangle (Solution) |
494. Target Sum (Solution) |
495. Teemo Attacking (Solution) |
| 496. Next Greater Element I (Solution) |
498. Diagonal Traverse (Solution) |
500. Keyboard Row (Solution) |
| 501. Find Mode in Binary Search Tree (Solution) |
503. Next Greater Element II (Solution) |
504. Base 7 (Solution) |
| 505. The Maze II (Solution) |
506. Relative Ranks (Solution) |
507. Perfect Number (Solution) |
| 508. Most Frequent Subtree Sum (Solution) |
513. Find Bottom Left Tree Value (Solution) |
515. Find Largest Value in Each Tree Row (Solution) |
| 516. Longest Palindromic Subsequence (Solution) |
518. Coin Change 2 (Solution) |
520. Detect Capital (Solution) |
| 521. Longest Uncommon Subsequence I (Solution) |
522. Longest Uncommon Subsequence II (Solution) |
523. Continuous Subarray Sum (Solution) |
| 524. Longest Word in Dictionary through Deleting (Solution) |
525. Contiguous Array (Solution) |
526. Beautiful Arrangement (Solution) |
| 529. Minesweeper (Solution) |
530. Minimum Absolute Difference in BST (Solution) |
531. Lonely Pixel I (Solution) |
| 532. K-diff Pairs in an Array (Solution) |
533. Lonely Pixel II (Solution) |
535. Encode and Decode TinyURL (Solution) |
| 536. Construct Binary Tree from String (Solution) |
537. Complex Number Multiplication (Solution) |
538. Convert BST to Greater Tree (Solution) |
| 539. Minimum Time Difference (Solution) |
540. Single Element in a Sorted Array (Solution) |
541. Reverse String II (Solution) |
| 542. 01 Matrix (Solution) |
543. Diameter of Binary Tree (Solution) |
544. Output Contest Matches (Solution) |
| 545. Boundary of Binary Tree (Solution) |
547. Friend Circles (Solution) |
548. Split Array with Equal Sum (Solution) |
| 549. Binary Tree Longest Consecutive Sequence II (Solution) |
551. Student Attendance Record I (Solution) |
553. Optimal Division (Solution) |
| 554. Brick Wall (Solution) |
555. Split Concatenated Strings (Solution) |
556. Next Greater Element III (Solution) |
| 557. Reverse Words in a String III (Solution) |
560. Subarray Sum Equals K (Solution) |
561. Array Partition I (Solution) |
| 562. Longest Line of Consecutive One in Matrix (Solution) |
563. Binary Tree Tilt (Solution) |
565. Array Nesting (Solution) |
| 566. Reshape the Matrix (Solution) |
567. Permutation in String (Solution) |
572. Subtree of Another Tree (Solution) |
| 573. Squirrel Simulation (Solution) |
576. Out of Boundary Paths (Solution) |
582. Kill Process (Solution) |
| 583. Delete Operation for Two Strings (Solution) |
592. Fraction Addition and Subtraction (Solution) |
593. Valid Square (Solution) |
| 609. Find Duplicate File in System (Solution) |
611. Valid Triangle Number (Solution) |
616. Add Bold Tag in String (Solution) |
| 621. Task Scheduler (Solution) |
623. Add One Row to Tree (Solution) |
625. Minimum Factorization (Solution) |
| 634. Find the Derangement of An Array (Solution) |
636. Exclusive Time of Functions (Solution) |
638. Shopping Offers (Solution) |
| 640. Solve the Equation (Solution) |
646. Maximum Length of Pair Chain (Solution) |
647. Palindromic Substrings (Solution) |
| 648. Replace Words (Solution) |
649. Dota2 Senate (Solution) |
650. 2 Keys Keyboard (Solution) |
| 651. 4 Keys Keyboard (Solution) |
652. Find Duplicate Subtrees (Solution) |
654. Maximum Binary Tree (Solution) |
| 655. Print Binary Tree (Solution) |
658. Find K Closest Elements (Solution) |
659. Split Array into Consecutive Subsequences (Solution) |
| 662. Maximum Width of Binary Tree (Solution) |
663. Equal Tree Partition (Solution) |
666. Path Sum IV (Solution) |
| 667. Beautiful Arrangement II (Solution) |
670. Maximum Swap (Solution) |
672. Bulb Switcher II (Solution) |
| 673. Number of Longest Increasing Subsequence (Solution) |
675. Cut Off Trees for Golf Event (Solution) |
676. Implement Magic Dictionary (Solution) |
| 677. Map Sum Pairs (Solution) |
678. Valid Parenthesis String (Solution) |
681. Next Closest Time (Solution) |
| 684. Redundant Connection (Solution) |
685. Redundant Connection II (Solution) |
688. Knight Probability in Chessboard (Solution) |
| 690. Employee Importance (Solution) |
692. Top K Frequent Words (Solution) |
694. Number of Distinct Islands (Solution) |
| 698. Partition to K Equal Sum Subsets (Solution) |
699. Falling Squares (Solution) |
711. Number of Distinct Islands II (Solution) |
| 712. Minimum ASCII Delete Sum for Two Strings (Solution) |
713. Subarray Product Less Than K (Solution) |
716. Max Stack (Solution) |
| 718. Maximum Length of Repeated Subarray (Solution) |
722. Remove Comments (Solution) |
723. Candy Crush (Solution) |
| 725. Split Linked List in Parts (Solution) |
729. My Calendar I (Solution) |
733. Flood Fill (Solution) |
| 734. Sentence Similarity (Solution) |
735. Asteroid Collision (Solution) |
737. Sentence Similarity II (Solution) |
| 738. Monotone Increasing Digits (Solution) |
739. Daily Temperatures (Solution) |
740. Delete and Earn (Solution) |
| 742. Closest Leaf in a Binary Tree (Solution) |
743. Network Delay Time (Solution) |
748. Shortest Completing Word (Solution) |
| 750. Number Of Corner Rectangles (Solution) |
752. Open the Lock (Solution) |
754. Reach a Number (Solution) |
| 755. Pour Water (Solution) |
756. Pyramid Transition Matrix (Solution) |
763. Partition Labels (Solution) |
| 764. Largest Plus Sign (Solution) |
767. Reorganize String (Solution) |
768. Max Chunks To Make Sorted II (Solution) |
| 769. Max Chunks To Make Sorted (Solution) |
775. Global and Local Inversions (Solution) |
777. Swap Adjacent in LR String (Solution) |
| 779. K-th Symbol in Grammar (Solution) |
781. Rabbits in Forest (Solution) |
785. Is Graph Bipartite? (Solution) |
| 787. Cheapest Flights Within K Stops (Solution) |
789. Escape The Ghosts (Solution) |
791. Custom Sort String (Solution) |
| 792. Number of Matching Subsequences (Solution) |
795. Number of Subarrays with Bounded Maximum (Solution) |
797. All Paths From Source to Target (Solution) |