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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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6 challenges matching your filters
Clear topic filter- Multiple ChoiceBeginner
Leader election with consensus
system-designconsensusleader-election - Multiple ChoiceIntermediate
Split-brain
system-designconsensusavailability - Multiple ChoiceIntermediate
Fencing tokens
system-designconsensusleader-election - Multiple ChoiceHard
Raft safety vs Paxos roles
raftpaxosconsensus - Code AnalysisHard
Split-brain from naive failover
system-designconsensusavailability - Code AnalysisHard
Fencing missing on lease-based lock
system-designconsensusleader-election
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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.