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 25 matching · 2723 totalSort: id ↑
No.ProblemDifficulty
- 0023Merge k Sorted ListsHard
- 0056Merge IntervalsMed
- 0121Best Time to Buy and Sell StockEasy
- 0136Single NumberEasy
- 0146LRU CacheMed
- 0148Sort ListMed
- 0188Number of IslandsMed
- 0205Contains DuplicateEasy
- 0207Contains Duplicate IIEasy
- 0208Contains Duplicate IIIHard
- 0260Integer to English WordsHard
- 0290Range Sum Query - ImmutableEasy
- 0394Trapping Rain Water IIHard
- 0414Construct Quad TreeMed
- 0523Minimum Time DifferenceMed
- 0675Accounts MergeMed
- 0687Flood FillEasy
- 0693Daily TemperaturesMed
- 1150Check If It Is a Straight LineEasy
- 1997All Ancestors of a Node in a Directed Acyclic GraphMed
Showing 20 of 25