| First Unique Number ↗ | Medium | Array, Hash Table, Design | |
| Minimum Edge Reversals So Every Node Is Reachable ↗ | Hard | Dynamic Programming, Depth-First Search, Breadth-First Search | |
| Number of Islands II ↗ | Hard | Array, Hash Table, Union-Find | |
| Longest Continuous Subarray With Absolute Diff Less Than or Equal to Limit ↗ | Medium | Array, Queue, Sliding Window | |
| Bus Routes ↗ | Hard | Array, Hash Table, Breadth-First Search | |
| Construct Quad Tree ↗ | Medium | Array, Divide and Conquer, Tree | |
| The Earliest Moment When Everyone Become Friends ↗ | Medium | Array, Union-Find, Sorting | |
| Alien Dictionary ↗ | Hard | Array, String, Depth-First Search | |
| Squares of a Sorted Array ↗ | Easy | Array, Two Pointers, Sorting | |
| Final Prices With a Special Discount in a Shop ↗ | Easy | Array, Stack, Monotonic Stack | |
| Kth Smallest Element in a BST ↗ | Medium | Tree, Depth-First Search, Binary Search Tree | |
| Design Hit Counter ↗ | Medium | Array, Binary Search, Design | |
| Number of Islands ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |
| Find Peak Element ↗ | Medium | Array, Binary Search | |
| Word Search ↗ | Medium | Array, String, Backtracking | |
| Split Array Largest Sum ↗ | Hard | Array, Binary Search, Dynamic Programming | |
| Time Based Key-Value Store ↗ | Medium | Hash Table, String, Binary Search | |
| Making A Large Island ↗ | Hard | Array, Depth-First Search, Breadth-First Search | |
| LRU Cache ↗ | Medium | Hash Table, Linked List, Design | |
| Insert Delete GetRandom O(1) ↗ | Medium | Array, Hash Table, Math | |
| Word Search II ↗ | Hard | Array, String, Backtracking | |
| Exam Room ↗ | Medium | Design, Heap (Priority Queue), Ordered Set | |
| Merge Intervals ↗ | Medium | Array, Sorting | |
| Course Schedule ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |
| Course Schedule II ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |
| Evaluate Division ↗ | Medium | Array, String, Depth-First Search | |
| IPO ↗ | Hard | Array, Greedy, Sorting | |
| Best Time to Buy and Sell Stock ↗ | Easy | Array, Dynamic Programming | |
| Longest Palindromic Substring ↗ | Medium | Two Pointers, String, Dynamic Programming | |
| Roman to Integer ↗ | Easy | Hash Table, Math, String | |
| Search in Rotated Sorted Array ↗ | Medium | Array, Binary Search | |
| Meeting Rooms II ↗ | Medium | Array, Two Pointers, Greedy | |
| Rotting Oranges ↗ | Medium | Array, Breadth-First Search, Matrix | |
| Find Median from Data Stream ↗ | Hard | Two Pointers, Design, Sorting | |
| Cheapest Flights Within K Stops ↗ | Medium | Dynamic Programming, Depth-First Search, Breadth-First Search | |
| Basic Calculator II ↗ | Medium | Math, String, Stack | |
| Serialize and Deserialize Binary Tree ↗ | Hard | String, Tree, Depth-First Search | |
| Minimum Jumps to Reach End via Prime Teleportation ↗ | Medium | Array, Hash Table, Math | |
| Find Eventual Safe States ↗ | Medium | Depth-First Search, Breadth-First Search, Graph Theory | |
| Shortest Bridge ↗ | Medium | Array, Depth-First Search, Breadth-First Search | |