| 4. Median of Two Sorted Arrays | Solution | Solve | Hard | | |
| 23. Merge k Sorted Lists | Solution | Solve | Hard | | |
| 25. Reverse Nodes in k-Group | Solution | Solve | Hard | | |
| 41. First Missing Positive | Solution | Solve | Hard | | |
| 42. Trapping Rain Water | Solution | Solve | Hard | | |
| 51. N-Queens | Solution | Solve | Hard | | |
| 76. Minimum Window Substring | Solution | Solve | Hard | | |
| 85. Maximal Rectangle | Solution | Solve | Hard | | |
| 115. Distinct Subsequences | Solution | Solve | Hard | | |
| 124. Binary Tree Maximum Path Sum | Solution | Solve | Hard | | |
| 127. Word Ladder | Solution | Solve | Hard | | |
| 135. Candy | Solution | Solve | Hard | | |
| 224. Basic Calculator | Solution | Solve | Hard | | |
| 233. Number of Digit One | Solution | Solve | Hard | | |
| 239. Sliding Window Maximum | Solution | Solve | Hard | | |
| 295. Find Median from Data Stream | Solution | Solve | Hard | | |
| 329. Longest Increasing Path in a Matrix | Solution | Solve | Hard | | |
| 332. Reconstruct Itinerary | Solution | Solve | Hard | | |
| 410. Split Array Largest Sum | Solution | Solve | Hard | | |
| 460. LFU Cache | Solution | Solve | Hard | | |
| 465. Optimal Account Balancing | Solution | Solve | Hard | | |
| 472. Concatenated Words | Solution | Solve | Hard | | |
| 502. IPO | Solution | Solve | Hard | | |
| 630. Course Schedule III | Solution | Solve | Hard | | |
| 768. Max Chunks To Make Sorted II | Solution | Solve | Hard | | |
| 815. Bus Routes | Solution | Solve | Hard | | |
| 895. Maximum Frequency Stack | Solution | Solve | Hard | | |
| 924. Minimize Malware Spread | Solution | Solve | Hard | | |
| 992. Subarrays with K Different Integers | Solution | Solve | Hard | | |
| 1326. Minimum Number of Taps to Open to Water a Garden | Solution | Solve | Hard | | |
| 1335. Minimum Difficulty of a Job Schedule | Solution | Solve | Hard | | |
| 1463. Cherry Pickup II | Solution | Solve | Hard | | |
| 1659. Maximize Grid Happiness | Solution | Solve | Hard | | |
| 1944. Number of Visible People in a Queue | Solution | Solve | Hard | | |
| 2025. Maximum Number of Ways to Partition an Array | Solution | Solve | Hard | | |
| 2035. Partition Array Into Two Arrays to Minimize Sum Difference | Solution | Solve | Hard | | |
| 2065. Maximum Path Quality of a Graph | Solution | Solve | Hard | | |
| 2296. Design a Text Editor | Solution | Solve | Hard | | |
| 2472. Maximum Number of Non-overlapping Palindrome Substrings | Solution | Solve | Hard | | |
| 2484. Count Palindromic Subsequences | Solution | Solve | Hard | | |
| 2488. Count Subarrays With Median K | Solution | Solve | Hard | | |
| 2603. Collect Coins in a Tree | Solution | Solve | Hard | | |
| 2954. Count the Number of Infection Sequences | Solution | Solve | Hard | | |
| 3171. Find Subarray With Bitwise OR Closest to K | Solution | Solve | Hard | | |
| 3193. Count the Number of Inversions | Solution | Solve | Hard | | |
| 3197. Find the Minimum Area to Cover All Ones II | Solution | Solve | Hard | | |
| 3313. Find the Last Marked Nodes in Tree | Solution | Solve | Hard | | |
| 3399. Smallest Substring With Identical Characters II | Solution | Solve | Hard | | |
| 3398. Smallest Substring With Identical Characters I | Solution | Solve | Hard | | |
