| 158. Read N Characters Given read4 II - Call Multiple Times | Solution | Solve | Hard | | |
| 248. Strobogrammatic Number III | Solution | Solve | Hard | - | |
| 265. Paint House II | Solution | Solve | Hard | | |
| 269. Alien Dictionary | Solution | Solve | Hard | | |
| 272. Closest Binary Search Tree Value II | Solution | Solve | Hard | | |
| 296. Best Meeting Point | Solution | Solve | Hard | | |
| 302. Smallest Rectangle Enclosing Black Pixels | Solution | Solve | Hard | | |
| 305. Number of Islands II | Solution | Solve | Hard | | |
| 317. Shortest Distance from All Buildings | Solution | Solve | Hard | | |
| 358. Rearrange String k Distance Apart | Solution | Solve | Hard | | |
| 411. Minimum Unique Word Abbreviation | Solution | Solve | Hard | | |
| 425. Word Squares | Solution | Solve | Hard | | |
| 428. Serialize and Deserialize N-ary Tree | Solution | Solve | Hard | | |
| 431. Encode N-ary Tree to Binary Tree | Solution | Solve | Hard | - | |
| 465. Optimal Account Balancing | Solution | Solve | Hard | | |
| 471. Encode String with Shortest Length | Solution | Solve | Hard | | |
| 489. Robot Room Cleaner | Solution | Solve | Hard | | |
| 499. The Maze III | Solution | Solve | Hard | | |
| 527. Word Abbreviation | Solution | Solve | Hard | | |
| 548. Split Array with Equal Sum | 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 | | |
| 588. Design In-Memory File System | Solution | Solve | Hard | | |
| 615. Average Salary: Departments VS Company | Solution | Solve | Hard | - | |
| 618. Students Report By Geography | Solution | Solve | Hard | - | |
| 631. Design Excel Sum Formula | 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 | | |
| 683. K Empty Slots | Solution | Solve | Hard | | |
| 711. Number of Distinct Islands II | Solution | Solve | Hard | | |
| 716. Max Stack | Solution | Solve | Hard | | |
| 727. Minimum Window Subsequence | Solution | Solve | Hard | | |
| 759. Employee Free Time | Solution | Solve | Hard | | |
| 772. Basic Calculator III | Solution | Solve | Hard | | |
| 774. Minimize Max Distance to Gas Station | Solution | Solve | Hard | | |
| 1063. Number of Valid Subarrays | Solution | Solve | Hard | | |
| 1067. Digit Count in Range | Solution | Solve | Hard | | |
| 1088. Confusing Number II | Solution | Solve | Hard | | |
| 1097. Game Play Analysis V | Solution | Solve | Hard | | |
| 1121. Divide Array Into Increasing Sequences | Solution | Solve | Hard | | |
| 1127. User Purchase Platform | Solution | Solve | Hard | | |
| 1153. String Transforms Into Another String | Solution | Solve | Hard | | |
| 1159. Market Analysis II | Solution | Solve | Hard | | |
| 1168. Optimize Water Distribution in a Village | Solution | Solve | Hard | | |
| 1183. Maximum Number of Ones | Solution | Solve | Hard | | |
| 1194. Tournament Winners | Solution | Solve | Hard | | |
