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.
Filter by type
Filter by difficulty
Popular topics
15 challenges matching your filters
Clear topic filter- Multiple ChoiceHard
[Algorithms] Search Ordered tree structure
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Insert Ordered tree structure
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Successor Ordered tree structure
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Delete Ordered tree structure
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Balance Ordered tree structure
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Priority queue Single-source shortest path
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Relaxation Single-source shortest path
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Negative edges Single-source shortest path
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] vs A* Single-source shortest path
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Dial's algorithm Single-source shortest path
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Top-down Subproblem memoization
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Bottom-up Subproblem memoization
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Knapsack Subproblem memoization
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] LCS Subproblem memoization
qaalgosalgosqa - Multiple ChoiceHard
[Algorithms] Optimal substructure Subproblem memoization
qaalgosalgosqa
Practice now, dominate the arena
Every challenge here is drawn from the live Code Royale pool. Review a question, then head to the arena to answer under pressure against a real opponent — 3-minute matches, Elo ranking, and badge tiers on the line.