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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 ChoiceIntermediate
Capacity estimation: peak vs average
system-designcapacity-estimation - Multiple ChoiceBeginner
Storage sizing with replication
system-designcapacity-estimationstorage - Multiple ChoiceBeginner
Bandwidth estimation
system-designcapacity-estimationbandwidth - Multiple ChoiceIntermediate
Read-heavy vs write-heavy design
system-designcapacity-estimationdatabases - Multiple ChoiceHard
Little's Law for concurrency
system-designcapacity-estimationlatency - Multiple ChoiceBeginner
Back-of-envelope QPS from DAU
capacity-estimationqpsback-of-envelope
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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.