| 616. Add Bold Tag in String | Solution | Solve | Medium | | |
| 621. Task Scheduler | Solution | Solve | Medium | | |
| 622. Design Circular Queue | Solution | Solve | Medium | | |
| 623. Add One Row to Tree | Solution | Solve | Medium | | |
| 624. Maximum Distance in Arrays | Solution | Solve | Medium | | |
| 625. Minimum Factorization | Solution | Solve | Medium | | |
| 626. Exchange Seats | Solution | Solve | Medium | | |
| 633. Sum of Square Numbers | Solution | Solve | Medium | | |
| 634. Find the Derangement of An Array | Solution | Solve | Medium | | |
| 635. Design Log Storage System | Solution | Solve | Medium | | |
| 636. Exclusive Time of Functions | Solution | Solve | Medium | | |
| 638. Shopping Offers | Solution | Solve | Medium | | |
| 640. Solve the Equation | Solution | Solve | Medium | | |
| 641. Design Circular Deque | Solution | Solve | Medium | | |
| 646. Maximum Length of Pair Chain | Solution | Solve | Medium | | |
| 647. Palindromic Substrings | Solution | Solve | Medium | | |
| 648. Replace Words | Solution | Solve | Medium | | |
| 649. Dota2 Senate | Solution | Solve | Medium | | |
| 650. 2 Keys Keyboard | Solution | Solve | Medium | | |
| 651. 4 Keys Keyboard | Solution | Solve | Medium | | |
| 652. Find Duplicate Subtrees | Solution | Solve | Medium | | |
| 654. Maximum Binary Tree | Solution | Solve | Medium | | |
| 655. Print Binary Tree | Solution | Solve | Medium | | |
| 658. Find K Closest Elements | Solution | Solve | Medium | | |
| 659. Split Array into Consecutive Subsequences | Solution | Solve | Medium | | |
| 662. Maximum Width of Binary Tree | Solution | Solve | Medium | | |
| 663. Equal Tree Partition | Solution | Solve | Medium | | |
| 665. Non-decreasing Array | Solution | Solve | Medium | | |
| 666. Path Sum IV | Solution | Solve | Medium | | |
| 667. Beautiful Arrangement II | Solution | Solve | Medium | | |
| 669. Trim a Binary Search Tree | Solution | Solve | Medium | | |
| 670. Maximum Swap | Solution | Solve | Medium | | |
| 672. Bulb Switcher II | Solution | Solve | Medium | | |
| 673. Number of Longest Increasing Subsequence | Solution | Solve | Medium | | |
| 676. Implement Magic Dictionary | Solution | Solve | Medium | | |
| 677. Map Sum Pairs | Solution | Solve | Medium | | |
| 678. Valid Parenthesis String | Solution | Solve | Medium | | |
| 681. Next Closest Time | Solution | Solve | Medium | | |
| 684. Redundant Connection | Solution | Solve | Medium | | |
| 686. Repeated String Match | Solution | Solve | Medium | | |
| 687. Longest Univalue Path | Solution | Solve | Medium | | |
| 688. Knight Probability in Chessboard | Solution | Solve | Medium | | |
| 690. Employee Importance | Solution | Solve | Medium | | |
| 692. Top K Frequent Words | Solution | Solve | Medium | | |
| 694. Number of Distinct Islands | Solution | Solve | Medium | | |
| 695. Max Area of Island | Solution | Solve | Medium | | |
| 698. Partition to K Equal Sum Subsets | Solution | Solve | Medium | | |
| 701. Insert into a Binary Search Tree | Solution | Solve | Medium | | |
| 702. Search in a Sorted Array of Unknown Size | Solution | Solve | Medium | | |
| 707. Design Linked List | Solution | Solve | Medium | | |
