171 problems
| Problem | Difficulty | Frequency ↓ | Topics |
|---|---|---|---|
| Expression Add Operators | Hard | 20.3% | TopicsMathStringBacktracking |
| 1944. Number of Visible People in a Queue | Hard | 20.3% | TopicsArrayStackMonotonic Stack |
| 1857. Largest Color Value in a Directed Graph | Hard | 20.3% | TopicsHash TableStringDynamic ProgrammingGraph TheoryTopological SortMemoizationCountingDirected Acyclic Graph |
| Integer to English Words | Hard | 20.3% | TopicsMathStringRecursion |
| 621. Task Scheduler | Medium | 20.3% | TopicsArrayHash TableGreedySortingHeap (Priority Queue)Counting |
| Find Minimum in Rotated Sorted Array | Medium | 20.3% | TopicsArrayBinary Search |
| 7. Reverse Integer | Medium | 20.3% | TopicsMath |
| 1473. Paint House III | Hard | 20.3% | TopicsArrayDynamic Programming |
| 1048. Longest String Chain | Medium | 20.3% | TopicsArrayHash TableTwo PointersStringDynamic ProgrammingSorting |
| 3113. Find the Number of Subarrays Where Boundary Elements Are Maximum | Hard | 20.3% | TopicsArrayBinary SearchStackMonotonic Stack |
| Longest Consecutive Sequence | Medium | 20.3% | TopicsArrayHash TableUnion-Find |
| 98. Validate Binary Search Tree | Medium | 20.3% | TopicsTreeDepth-First SearchBinary Search TreeBinary Tree |
| The Maze | Medium | 20.3% | TopicsArrayDepth-First SearchBreadth-First SearchMatrix |
| 1017. Convert to Base -2 | Medium | 20.3% | TopicsMath |
| Insert into a Binary Search Tree | Medium | 20.3% | TopicsTreeBinary Search TreeBinary Tree |
| 387. First Unique Character in a String | Easy | 20.3% | TopicsHash TableStringQueueCounting |
| 206. Reverse Linked List | Easy | 20.3% | TopicsLinked ListRecursion |
| 863. All Nodes Distance K in Binary Tree | Medium | 20.3% | TopicsHash TableTreeDepth-First SearchBreadth-First SearchBinary Tree |
| 1297. Maximum Number of Occurrences of a Substring | Medium | 20.3% | TopicsHash TableStringSliding Window |
| 234. Palindrome Linked List | Easy | 20.3% | TopicsLinked ListTwo PointersStackRecursion |
| Unique Binary Search Trees | Medium | 20.3% | TopicsMathDynamic ProgrammingTreeBinary Search TreeBinary Tree |
