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
19 of 19 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0005Longest Palindromic SubstringMed
- 0049Group AnagramsMed
- 0125Valid PalindromeEasy
- 0151Reverse Words in a StringMed
- 0152Maximum Product SubarrayMed
- 0227Sliding Window MaximumHard
- 0287Longest Increasing SubsequenceMed
- 0402Add StringsEasy
- 0601Palindromic SubstringsMed
- 0734Reaching PointsHard
- 0798Backspace String CompareEasy
- 0968Best Sightseeing PairMed
- 1114Maximum Number of BalloonsEasy
- 1301Longest Happy StringMed
- 1345Maximum Number of Vowels in a Substring of Given LengthMed
- 1475Alert Using Same Key-Card Three or More Times in a One Hour PeriodMed
- 1729Largest Magic SquareMed
- 1784Delete Characters to Make Fancy StringEasy
- 1949Minimum Moves to Reach Target ScoreMed
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