| 261. Graph Valid Tree | | | Solve | Medium | | |
| 265. Paint House II | | | Solve | Hard | | |
| 271. Encode and Decode Strings | | | Solve | Medium | | |
| 272. Closest Binary Search Tree Value II | | | Solve | Hard | | |
| 277. Find the Celebrity | | | Solve | Medium | | |
| 295. Find Median from Data Stream | | | Solve | Hard | | |
| 297. Serialize and Deserialize Binary Tree | | | Solve | Hard | | |
| 319. Bulb Switcher | | | Solve | Medium | | |
| 323. Number of Connected Components in an Undirected Graph | | | Solve | Medium | | |
| 339. Nested List Weight Sum | | | Solve | Medium | | |
| 341. Flatten Nested List Iterator | | | Solve | Medium | | |
| 360. Sort Transformed Array | | | Solve | Medium | | |
| 364. Nested List Weight Sum II | | | Solve | Medium | | |
| 366. Find Leaves of Binary Tree | | | Solve | Medium | | |
| 367. Valid Perfect Square | | | Solve | Easy | | |
| 373. Find K Pairs with Smallest Sums | | | Solve | Medium | | |
| 380. Insert Delete GetRandom O(1) | | | Solve | Medium | | |
| 381. Insert Delete GetRandom O(1) - Duplicates allowed | | | Solve | Hard | | |
| 432. All O`one Data Structure | | | Solve | Hard | | |
| 449. Serialize and Deserialize BST | | | Solve | Medium | | |
| 450. Delete Node in a BST | | | Solve | Medium | | |
| 460. LFU Cache | | | Solve | Hard | | |
| 464. Can I Win | | | Solve | Medium | | |
| 515. Find Largest Value in Each Tree Row | | | Solve | Medium | | |
| 516. Longest Palindromic Subsequence | | | Solve | Medium | | |
| 518. Coin Change II | | | Solve | Medium | | |
| 528. Random Pick with Weight | | | Solve | Medium | | |
| 605. Can Place Flowers | | | Solve | Easy | | |
| 611. Valid Triangle Number | | | Solve | Medium | | |
| 636. Exclusive Time of Functions | | | Solve | Medium | | |
| 642. Design Search Autocomplete System | | | Solve | Hard | | |
| 655. Print Binary Tree | | | Solve | Medium | | |
| 671. Second Minimum Node In a Binary Tree | | | Solve | Easy | | |
| 678. Valid Parenthesis String | | | Solve | Medium | | |
| 695. Max Area of Island | | | Solve | Medium | | |
| 698. Partition to K Equal Sum Subsets | | | Solve | Medium | | |
| 701. Insert into a Binary Search Tree | | | Solve | Medium | | |
| 703. Kth Largest Element in a Stream | | | Solve | Easy | | |
| 706. Design HashMap | | | Solve | Easy | | |
| 716. Max Stack | | | Solve | Hard | | |
| 721. Accounts Merge | | | Solve | Medium | | |
| 730. Count Different Palindromic Subsequences | | | Solve | Hard | | |
| 744. Find Smallest Letter Greater Than Target | | | Solve | Easy | | |
| 796. Rotate String | | | Solve | Easy | | |
| 833. Find And Replace in String | | | Solve | Medium | | |
| 895. Maximum Frequency Stack | | | Solve | Hard | | |
| 953. Verifying an Alien Dictionary | | | Solve | Easy | | |
| 973. K Closest Points to Origin | | | Solve | Medium | | |
| 994. Rotting Oranges | | | Solve | Medium | | |
| 1041. Robot Bounded In Circle | | | Solve | Medium | | |
