DSA
Master the patterns
Search the bank, then filter by difficulty, pattern, data structure, or algorithm. Each problem includes approaches, solutions, and walkthroughs.
Active·2,723
Easy·667
Medium·1,394
Hard·662
Patterns
Recognize the move
Filter the bank by pattern — each card links into the problem index.
Problem index
Browse problems
Search by title, then refine with facets. Sorted by problem ID.
Difficulty
Facets
20 of 66 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0002Add Two NumbersMed
- 0019Remove Nth Node From End of ListMed
- 0021Merge Two Sorted ListsEasy
- 0023Merge k Sorted ListsHard
- 0024Swap Nodes in PairsMed
- 0025Reverse Nodes in k-GroupHard
- 0061Rotate ListMed
- 0082Remove Duplicates from Sorted List IIMed
- 0083Remove Duplicates from Sorted ListEasy
- 0086Partition ListMed
- 0092Reverse Linked List IIMed
- 0109Convert Sorted List to Binary Search TreeMed
- 0114Flatten Binary Tree to Linked ListMed
- 0116Populating Next Right Pointers in Each NodeMed
- 0117Populating Next Right Pointers in Each Node IIMed
- 0138Copy List with Random PointerMed
- 0141Linked List CycleEasy
- 0142Linked List Cycle IIMed
- 0143Reorder ListMed
- 0146LRU CacheMed
Showing 20 of 66