Challenge Library
Coding Challenges
5,893 curated questions across every arena — browse by topic, then jump into a live 3-minute battle to put them to the test.
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423 challenges matching your filters
Clear topic filter- Multiple ChoiceBeginner
Fixed vs Dynamic Arrays
dsaarraysbeginner - Multiple ChoiceBeginner
Arrays: Indexing
dsaarraysbeginner - Multiple ChoiceBeginner
Arrays: Insert at End
dsaarraysbeginner - Multiple ChoiceBeginner
Arrays: Insert in Middle
dsaarraysbeginner - Multiple ChoiceBeginner
Arrays: Memory Layout
dsaarraysbeginner - Multiple ChoiceBeginner
Arrays vs Linked Lists
dsaarraysbeginner - Multiple ChoiceIntermediate
Backtracking: Definition
dsabacktrackingintermediate - Multiple ChoiceIntermediate
Backtracking: N-Queens
dsabacktrackingintermediate - Multiple ChoiceIntermediate
Backtracking: Permutations
dsabacktrackingintermediate - Multiple ChoiceIntermediate
Backtracking: Pruning
dsabacktrackingintermediate - Multiple ChoiceBeginner
Big-O: Definition
dsabig-obeginner - Multiple ChoiceBeginner
O(1) — Constant Time
dsabig-obeginner - Multiple ChoiceBeginner
O(n) — Linear Time
dsabig-obeginner - Multiple ChoiceBeginner
O(n²) — Quadratic Time
dsabig-obeginner - Multiple ChoiceIntermediate
Merge Sort
dsadivide-conquerintermediate - Multiple ChoiceIntermediate
Quick Sort
dsadivide-conquerintermediate - Multiple ChoiceIntermediate
DP: Definition
dsadpintermediate - Multiple ChoiceHard
Edit Distance (Levenshtein)
dsadphard - Multiple ChoiceIntermediate
DP: Fibonacci Optimization
dsadpintermediate - Multiple ChoiceHard
0/1 Knapsack
dsadphard - Multiple ChoiceHard
Longest Common Subsequence
dsadphard - Multiple ChoiceIntermediate
Memoization
dsadpintermediate - Multiple ChoiceHard
Subset Sum
dsadphard - Multiple ChoiceIntermediate
Tabulation
dsadpintermediate - Multiple ChoiceIntermediate
DP vs Greedy
dsadpintermediate - Multiple ChoiceHard
DP vs Naive Recursion
dsadphard - Multiple ChoiceHard
Fenwick Tree (BIT)
dsafenwick-treehard - Multiple ChoiceHard
Fenwick vs Segment Tree
dsafenwick-treehard - Multiple ChoiceIntermediate
Adjacency List
dsagraphsintermediate - Multiple ChoiceHard
Bellman-Ford Algorithm
dsagraphshard - Multiple ChoiceIntermediate
Breadth-First Search (BFS)
dsagraphsintermediate - Multiple ChoiceIntermediate
BFS: Use Cases
dsagraphsintermediate - Multiple ChoiceIntermediate
Graph: Definition
dsagraphsintermediate - Multiple ChoiceIntermediate
Depth-First Search (DFS)
dsagraphsintermediate - Multiple ChoiceIntermediate
DFS: Use Cases
dsagraphsintermediate - Multiple ChoiceHard
Dijkstra's Algorithm
dsagraphshard - Multiple ChoiceIntermediate
Directed vs Undirected Graphs
dsagraphsintermediate - Multiple ChoiceHard
Floyd-Warshall Algorithm
dsagraphshard - Multiple ChoiceHard
Minimum Spanning Tree
dsagraphshard - Multiple ChoiceHard
Strongly Connected Components
dsagraphshard - Multiple ChoiceHard
Topological Sort
dsagraphshard - Multiple ChoiceIntermediate
Weighted Graph
dsagraphsintermediate - Multiple ChoiceIntermediate
Greedy: Coin Change
dsagreedyintermediate - Multiple ChoiceIntermediate
Greedy: Definition
dsagreedyintermediate - Multiple ChoiceIntermediate
Greedy: Limitation
dsagreedyintermediate - Multiple ChoiceBeginner
Hash Table: Collision
dsahash-tablebeginner - Multiple ChoiceBeginner
Hash Table: Definition
dsahash-tablebeginner - Multiple ChoiceBeginner
Hash Table: Lookup
dsahash-tablebeginner - Multiple ChoiceBeginner
Hash Table vs Array
dsahash-tablebeginner - Multiple ChoiceIntermediate
Heap: Definition
dsaheapsintermediate - Multiple ChoiceIntermediate
Heap: Insert Complexity
dsaheapsintermediate - Multiple ChoiceIntermediate
Max-Heap vs Min-Heap
dsaheapsintermediate - Multiple ChoiceBeginner
Linked List: Definition
dsalinked-listbeginner - Multiple ChoiceBeginner
Head and Tail
dsalinked-listbeginner - Multiple ChoiceBeginner
Singly vs Doubly Linked List
dsalinked-listbeginner - Multiple ChoiceBeginner
Linked List: Node Visiting
dsalinked-listbeginner - Multiple ChoiceBeginner
LL vs Array: Access
dsalinked-listbeginner - Multiple ChoiceBeginner
LL vs Array: Insert at Head
dsalinked-listbeginner - Multiple ChoiceHard
Amortized Cost
dsamcqhard - Multiple ChoiceIntermediate
BFS vs DFS
dsamcqintermediate
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