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 37 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0001Two SumEasy
- 0005Longest Palindromic SubstringMed
- 0011Container With Most WaterMed
- 0014Longest Common PrefixEasy
- 0020Valid ParenthesesEasy
- 0026Remove Duplicates from Sorted ArrayEasy
- 0042Trapping Rain WaterHard
- 0049Group AnagramsMed
- 0053Maximum SubarrayMed
- 0069Sqrt(x)Easy
- 0104Maximum Depth of Binary TreeEasy
- 0121Best Time to Buy and Sell StockEasy
- 0125Valid PalindromeEasy
- 0128Longest Consecutive SequenceMed
- 0139Word BreakMed
- 0141Linked List CycleEasy
- 0146LRU CacheMed
- 0188Number of IslandsMed
- 0194Reverse Linked ListEasy
- 0203Kth Largest Element in an ArrayMed
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