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 40 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0002Add Two NumbersMed
- 0010Regular Expression MatchingHard
- 0021Merge Two Sorted ListsEasy
- 0024Swap Nodes in PairsMed
- 0025Reverse Nodes in k-GroupHard
- 0044Wildcard MatchingHard
- 0050Pow(x, n)Med
- 0060Permutation SequenceHard
- 0143Reorder ListMed
- 0191Remove Linked List ElementsEasy
- 0194Reverse Linked ListEasy
- 0212Basic CalculatorHard
- 0219Power of TwoEasy
- 0221Number of Digit OneHard
- 0222Palindrome Linked ListEasy
- 0229Different Ways to Add ParenthesesMed
- 0260Integer to English WordsHard
- 0313Power of ThreeEasy
- 0329Power of FourEasy
- 0377Elimination GameMed
Showing 20 of 40