| 1 |
156. Binary Tree Upside Down |
Middle |
Solution |
| 2 |
157. Read N Characters Given Read4 |
Easy |
Solution |
| 3 |
158. Read N Characters Given Read4 II - Call multiple times |
Difficult |
Solution |
| 4 |
159. Longest Substring with At Most Two Distinct Characters |
Difficult |
Solution |
| 5 |
161. One Edit Distance |
Middle |
Solution |
| 6 |
163. Missing Ranges |
Middle |
Solution |
| 7 |
170. Two Sum III - Data structure design |
Easy |
Solution |
| 8 |
186. Reverse Words in a String II |
Middle |
Solution |
| 9 |
243. Shortest Word Distance |
Easy |
Solution |
| 10 |
244. Shortest Word Distance II |
Middle |
Solution |
| 11 |
245. Shortest Word Distance III |
Middle |
Solution |
| 12 |
246. Strobogrammatic Number |
Easy |
Solution |
| 13 |
247. Strobogrammatic Number II |
Middle |
Solution |
| 14 |
248. Strobogrammatic Number III |
Difficult |
Solution |
| 15 |
249. Group Shifted Strings |
Middle |
Solution |
| 16 |
250. Count Univalue Subtrees |
Middle |
Solution |
| 17 |
251. Flatten 2D Vector |
Middle |
Solution |
| 18 |
252. Meeting Rooms |
Easy |
Solution |
| 19 |
253. Meeting Rooms II |
Middle |
Solution |
| 20 |
254. Factor Combinations |
Middle |
Solution |
| 21 |
255. Verify Preorder Sequence in Binary Search Tree |
Middle |
Solution |
| 22 |
256. Paint House |
Easy |
Solution |
| 23 |
259. 3Sum Smaller |
Middle |
Solution |
| 24 |
261. Graph Valid Tree |
Middle |
Solution |
| 25 |
265. Paint House II |
Difficult |
Solution |
| 26 |
266. Palindrome Permutation |
Easy |
Solution |
| 27 |
267. Palindrome Permutation II |
Middle |
Solution |
| 28 |
269. Alien Dictionary |
Difficult |
Solution |
| 29 |
270. Closest Binary Search Tree Value |
Easy |
Solution |
| 30 |
271. Encode and Decode Strings |
Middle |
Solution |
| 31 |
272. Closest Binary Search Tree Value II |
Difficult |
Solution |
| 32 |
276. Paint Fence |
Easy |
Solution |
| 33 |
277. Find the Celebrity |
Middle |
Solution |
| 34 |
280. Wiggle Sort |
Middle |
Solution |
| 35 |
281. Zigzag Iterator |
Middle |
Solution |
| 36 |
285. Inorder Successor in BST |
Middle |
Solution |
| 37 |
286. Walls and Gates |
Middle |
Solution |
| 38 |
288. Unique Word Abbreviation |
Middle |
Solution |
| 39 |
291. Word Pattern II |
Difficult |
Solution |
| 40 |
293. Flip Game |
Easy |
Solution |
| 41 |
294. Flip Game II |
Middle |
Solution |
| 42 |
296. Best Meeting Point |
Difficult |
Solution |
| 43 |
298. Binary Tree Longest Consecutive Sequence |
Middle |
Solution |
| 44 |
302. Smallest Rectangle Enclosing Black Pixels |
Difficult |
Solution |
| 45 |
305. Number of Islands II |
Difficult |
Solution |
| 46 |
308. Range Sum Query 2D - Mutable |
Difficult |
Solution |
| 47 |
311. Sparse Matrix Multiplication |
Middle |
Solution |
| 48 |
314. Binary Tree Vertical Order Traversal |
Middle |
Solution |
| 49 |
317. Shortest Distance from All Buildings |
Difficult |
Solution |
| 50 |
320. Generalized Abbreviation |
Middle |
Solution |
| 51 |
323. Number of Connected Components in an Undirected Graph |
Middle |
Solution |
| 52 |
325. Maximum Size Subarray Sum Equals k |
Middle |
Solution |
| 53 |
333. Largest BST Subtree |
Middle |
Solution |
| 54 |
339. Nested List Weight Sum |
Easy |
Solution |
| 55 |
340. Longest Substring with At Most K Distinct Characters |
Difficult |
Solution |
| 56 |
346. Moving Average from Data Stream |
Easy |
Solution |
| 57 |
348. Design Tic-Tac-Toe |
Middle |
Solution |
| 58 |
351. Android Unlock Patterns |
Middle |
Solution |
| 59 |
353. Design Snake Game |
Middle |
Solution |
| 60 |
356. Line Reflection |
Middle |
Solution |
| 61 |
358. Rearrange String k Distance Apart |
Difficult |
Solution |
| 62 |
359. Logger Rate Limiter |
Easy |
Solution |
| 63 |
360. Sort Transformed Array |
Middle |
Solution |
| 64 |
361. Bomb Enemy |
Middle |
Solution |
| 65 |
362. Design Hit Counter |
Middle |
Solution |
| 66 |
364. Nested List Weight Sum II |
Middle |
Solution |
| 67 |
366. Find Leaves of Binary Tree |
Middle |
Solution |
| 68 |
369. Plus One Linked List |
Middle |
Solution |
| 69 |
370. Range Addition |
Middle |
Solution |
| 70 |
379. Design Phone Directory |
Middle |
Solution |
| 71 |
408. Valid Word Abbreviation |
Easy |
Solution |
| 72 |
411. Minimum Unique Word Abbreviation |
Difficult |
Solution |
| 73 |
418. Sentence Screen Fitting |
Middle |
Solution |
| 74 |
422. Valid Word Square |
Easy |
Solution |
| 75 |
425. Word Squares |
Difficult |
Solution |
| 76 |
439. Ternary Expression Parser |
Middle |
Solution |
| 77 |
444. Sequence Reconstruction |
Middle |
Solution |
| 78 |
465. Optimal Account Balancing |
Difficult |
Solution |
| 79 |
469. Convex Polygon |
Middle |
Solution |
| 80 |
471. Encode String with Shortest Length |
Difficult |
Solution |
| 81 |
484. Find Permutation |
Middle |
Solution |
| 82 |
487. Max Consecutive Ones II |
Middle |
Solution |
| 83 |
490. The Maze |
Middle |
Solution |
| 84 |
499. The Maze III |
Difficult |
Solution |
| 85 |
505. The Maze II |
Middle |
Solution |
| 86 |
527. Word Abbreviation |
Difficult |
Solution |
| 87 |
531. Lonely Pixel I |
Middle |
Solution |
| 88 |
533. Lonely Pixel II |
Middle |
Solution |
| 89 |
536. Construct Binary Tree from String |
Middle |
Solution |
| 90 |
544. Output Contest Matches |
Middle |
Solution |
| 91 |
545. Boundary of Binary Tree |
Middle |
Solution |
| 92 |
548. Split Array with Equal Sum |
Middle |
Solution |
| 93 |
549. Binary Tree Longest Consecutive Sequence II |
Middle |
Solution |
| 94 |
555. Split Concatenated Strings |
Middle |
Solution |
| 95 |
562. Longest Line of Consecutive One in Matrix |
Middle |
Solution |
| 96 |
568. Maximum Vacation Days |
Difficult |
Solution |
| 97 |
569. Median Employee Salary |
Difficult |
Solution |
| 98 |
570. Managers with at Least 5 Direct Reports |
Middle |
Solution |
| 99 |
571. Find Median Given Frequency of Numbers |
Difficult |
Solution |
| 100 |
573. Squirrel Simulation |
Middle |
Solution |
| 101 |
574. Winning Candidate |
Middle |
Solution |
| 102 |
577. Employee Bonus |
Easy |
Solution |
| 103 |
578. Get Highest Answer Rate Question |
Middle |
Solution |
| 104 |
579. Find Cumulative Salary of an Employee |
Difficult |
Solution |
| 105 |
580. Count Student Number in Departments |
Middle |
Solution |
| 106 |
582. Kill Process |
Middle |
Solution |
| 107 |
584. Find Customer Referee |
Easy |
Solution |
| 108 |
585. Investments in 2016 |
Middle |
Solution |
| 109 |
586. Customer Placing the Largest Number of Orders |
Easy |
Solution |
| 110 |
588. Design In-Memory File System |
Difficult |
Solution |
| 111 |
597. Friend Requests I: Overall Acceptance Rate |
Easy |
Solution |
| 112 |
602. Friend Requests II: Who Has the Most Friends |
Middle |
Solution |
| 113 |
603. Consecutive Available Seats |
Easy |
Solution |
| 114 |
604. Design Compressed String Iterator |
Easy |
Solution |
| 115 |
607. Sales Person |
Easy |
Solution |
| 116 |
608. Tree Node |
Middle |
Solution |
| 117 |
610. Triangle Judgement |
Easy |
Solution |
| 118 |
612. Shortest Distance in a Plane |
Middle |
Solution |
| 119 |
613. Shortest Distance in a Line |
Easy |
Solution |
| 120 |
614. Second Degree Follower |
Middle |
Solution |
| 121 |
615. Average Salary: Departments VS Company |
Difficult |
Solution |
| 122 |
616. Add Bold Tag in String |
Middle |
Solution |
| 123 |
618. Students Report By Geography |
Difficult |
Solution |
| 124 |
619. Biggest Single Number |
Easy |
Solution |
| 125 |
624. Maximum Distance in Arrays |
Easy |
Solution |
| 126 |
625. Minimum Factorization |
Middle |
Solution |
| 127 |
631. Design Excel Sum Formula |
Difficult |
Solution |
| 128 |
634. Find the Derangement of An Array |
Middle |
Solution |
| 129 |
635. Design Log Storage System |
Middle |
Solution |
| 130 |
642. Design Search Autocomplete System |
Difficult |
Solution |
| 131 |
644. Maximum Average Subarray II |
Difficult |
Solution |
| 132 |
651. 4 Keys Keyboard |
Middle |
Solution |
| 133 |
656. Coin Path |
Difficult |
Solution |
| 134 |
660. Remove 9 |
Difficult |
Solution |
| 135 |
663. Equal Tree Partition |
Middle |
Solution |
| 136 |
666. Path Sum IV |
Middle |
Solution |
| 137 |
681. Next Closest Time |
Middle |
Solution |
| 138 |
683. K Empty Slots |
Difficult |
Solution |
| 139 |
694. Number of Distinct Islands |
Middle |
Solution |
| 140 |
711. Number of Distinct Islands II |
Difficult |
Solution |
| 141 |
716. Max Stack |
Easy |
Solution |
| 142 |
723. Candy Crush |
Middle |
Solution |
| 143 |
727. Minimum Window Subsequence |
Difficult |
Solution |
| 144 |
734. Sentence Similarity |
Easy |
Solution |
| 145 |
737. Sentence Similarity II |
Middle |
Solution |
| 146 |
743. Closest Leaf in a Binary Tree |
Middle |
Solution |
| 147 |
751. Number Of Corner Rectangles |
Middle |
Solution |
| 148 |
752. IP to CIDR |
Easy |
Solution |
| 149 |
756. Pour Water |
Middle |
Solution |
| 150 |
758. Convert Binary Search Tree to Sorted Doubly Linked List |
Middle |
Solution |
| 151 |
760. Bold Words in String |
Easy |
Solution |
| 152 |
761. Employee Free Time |
Difficult |
Solution |
| 153 |
762. Find Anagram Mappings |
Easy |
Solution |
| 154 |
765. Serialize and Deserialize N-ary Tree |
Difficult |
Solution |
| 155 |
771. Encode N-ary Tree to Binary Tree |
Difficult |
Solution |
| 156 |
785. Basic Calculator III |
Difficult |
Solution |
| 157 |
786. Search in a Sorted Array of Unknown Size |
Middle |
Solution |
| 158 |
788. Minimize Max Distance to Gas Station |
Difficult |
Solution |
| 159 |
791. Split BST |
Middle |
Solution |
| 160 |
818. Similar RGB Color |
Easy |
Solution |
| 161 |
850. Insert into a Cyclic Sorted List |
Middle |
Solution |
| 162 |
865. Robot Room Cleaner |
Difficult |
Solution |