| 564. Find the Closest Palindrome | Solution | Solve | Hard | | |
| 568. Maximum Vacation Days | Solution | Solve | Hard | | |
| 569. Median Employee Salary | Solution | Solve | Hard | | |
| 571. Find Median Given Frequency of Numbers | Solution | Solve | Hard | | |
| 579. Find Cumulative Salary of an Employee | Solution | Solve | Hard | | |
| 587. Erect the Fence | Solution | Solve | Hard | | |
| 588. Design In-Memory File System | Solution | Solve | Hard | | |
| 591. Tag Validator | Solution | Solve | Hard | | |
| 600. Non-negative Integers without Consecutive Ones | Solution | Solve | Hard | | |
| 601. Human Traffic of Stadium | Solution | Solve | Hard | | |
| 615. Average Salary: Departments VS Company | Solution | Solve | Hard | - | |
| 618. Students Report By Geography | Solution | Solve | Hard | - | |
| 629. K Inverse Pairs Array | Solution | Solve | Hard | | |
| 630. Course Schedule III | Solution | Solve | Hard | | |
| 631. Design Excel Sum Formula | Solution | Solve | Hard | | |
| 632. Smallest Range Covering Elements from K Lists | Solution | Solve | Hard | | |
| 639. Decode Ways II | Solution | Solve | Hard | | |
| 642. Design Search Autocomplete System | Solution | Solve | Hard | | |
| 644. Maximum Average Subarray II | Solution | Solve | Hard | | |
| 656. Coin Path | Solution | Solve | Hard | | |
| 660. Remove 9 | Solution | Solve | Hard | | |
| 664. Strange Printer | Solution | Solve | Hard | | |
| 668. Kth Smallest Number in Multiplication Table | Solution | Solve | Hard | | |
| 675. Cut Off Trees for Golf Event | Solution | Solve | Hard | | |
| 679. 24 Game | Solution | Solve | Hard | | |
| 683. K Empty Slots | Solution | Solve | Hard | | |
| 685. Redundant Connection II | Solution | Solve | Hard | | |
| 689. Maximum Sum of 3 Non-Overlapping Subarrays | Solution | Solve | Hard | | |
| 691. Stickers to Spell Word | Solution | Solve | Hard | | |
| 699. Falling Squares | Solution | Solve | Hard | | |
| 710. Random Pick with Blacklist | Solution | Solve | Hard | | |
| 711. Number of Distinct Islands II | Solution | Solve | Hard | | |
| 715. Range Module | Solution | Solve | Hard | | |
| 716. Max Stack | Solution | Solve | Hard | | |
| 719. Find K-th Smallest Pair Distance | Solution | Solve | Hard | | |
| 726. Number of Atoms | Solution | Solve | Hard | | |
| 727. Minimum Window Subsequence | Solution | Solve | Hard | | |
| 730. Count Different Palindromic Subsequences | Solution | Solve | Hard | | |
| 732. My Calendar III | Solution | Solve | Hard | | |
| 736. Parse Lisp Expression | Solution | Solve | Hard | | |
| 741. Cherry Pickup | Solution | Solve | Hard | | |
| 745. Prefix and Suffix Search | Solution | Solve | Hard | | |
| 749. Contain Virus | Solution | Solve | Hard | | |
| 753. Cracking the Safe | Solution | Solve | Hard | | |
| 757. Set Intersection Size At Least Two | Solution | Solve | Hard | | |
| 759. Employee Free Time | Solution | Solve | Hard | | |
| 761. Special Binary String | Solution | Solve | Hard | | |
| 765. Couples Holding Hands | Solution | Solve | Hard | | |
| 768. Max Chunks To Make Sorted II | Solution | Solve | Hard | | |
| 770. Basic Calculator IV | Solution | Solve | Hard | | |
