| 4. Median of Two Sorted Arrays | | | Solve | Hard | | |
| 10. Regular Expression Matching | | | Solve | Hard | | |
| 23. Merge k Sorted Lists | | | Solve | Hard | | |
| 37. Sudoku Solver | | | Solve | Hard | | |
| 41. First Missing Positive | | | Solve | Hard | | |
| 42. Trapping Rain Water | | | Solve | Hard | | |
| 51. N-Queens | | | Solve | Hard | | |
| 60. Permutation Sequence | | | Solve | Hard | | |
| 68. Text Justification | | | Solve | Hard | | |
| 76. Minimum Window Substring | | | Solve | Hard | | |
| 84. Largest Rectangle in Histogram | | | Solve | Hard | | |
| 124. Binary Tree Maximum Path Sum | | | Solve | Hard | | |
| 127. Word Ladder | | | Solve | Hard | | |
| 135. Candy | | | Solve | Hard | | |
| 140. Word Break II | | | Solve | Hard | | |
| 220. Contains Duplicate III | | | Solve | Hard | | |
| 224. Basic Calculator | | | Solve | Hard | | |
| 239. Sliding Window Maximum | | | Solve | Hard | | |
| 262. Trips and Users | | | Solve | Hard | | |
| 295. Find Median from Data Stream | | | Solve | Hard | | |
| 315. Count of Smaller Numbers After Self | | | Solve | Hard | | |
| 327. Count of Range Sum | | | Solve | Hard | | |
| 403. Frog Jump | | | Solve | Hard | | |
| 446. Arithmetic Slices II - Subsequence | | | Solve | Hard | | |
| 458. Poor Pigs | | | Solve | Hard | | |
| 632. Smallest Range Covering Elements from K Lists | | | Solve | Hard | | |
| 768. Max Chunks To Make Sorted II | | | Solve | Hard | | |
| 770. Basic Calculator IV | | | Solve | Hard | | |
| 793. Preimage Size of Factorial Zeroes Function | | | Solve | Hard | | |
| 827. Making A Large Island | | | Solve | Hard | | |
| 862. Shortest Subarray with Sum at Least K | | | Solve | Hard | | |
| 895. Maximum Frequency Stack | | | Solve | Hard | | |
| 924. Minimize Malware Spread | | | Solve | Hard | | |
| 992. Subarrays with K Different Integers | | | Solve | Hard | | |
| 1095. Find in Mountain Array | | | Solve | Hard | | |
| 1192. Critical Connections in a Network | | | Solve | Hard | | |
| 1235. Maximum Profit in Job Scheduling | | | Solve | Hard | | |
| 1312. Minimum Insertion Steps to Make a String Palindrome | | | Solve | Hard | | |
| 1326. Minimum Number of Taps to Open to Water a Garden | | | Solve | Hard | | |
| 1483. Kth Ancestor of a Tree Node | | | Solve | Hard | | |
| 1489. Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree | | | Solve | Hard | | |
| 1531. String Compression II | | | Solve | Hard | | |
| 1601. Maximum Number of Achievable Transfer Requests | | | Solve | Hard | | |
| 1723. Find Minimum Time to Finish All Jobs | | | Solve | Hard | | |
| 1751. Maximum Number of Events That Can Be Attended II | | | Solve | Hard | | |
| 1916. Count Ways to Build Rooms in an Ant Colony | | | Solve | Hard | | |
| 2035. Partition Array Into Two Arrays to Minimize Sum Difference | | | Solve | Hard | | |
| 2092. Find All People With Secret | | | Solve | Hard | | |
| 2143. Choose Numbers From Two Arrays in Range | | | Solve | Hard | | |
| 2328. Number of Increasing Paths in a Grid | | | Solve | Hard | | |