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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120 challenges matching your filters
Clear topic filter- Code AnalysisHard
Trace: Nil Map Read
goanalysishard - Code AnalysisHard
Trace: Slice Append Aliasing
goanalysishard - Code AnalysisHard
Trace: Bit Op #1
goanalysishard - Code AnalysisHard
Trace: Bit Op #2
goanalysishard - Code AnalysisHard
Trace: Bit Op #3
goanalysishard - Code AnalysisHard
Trace: Bit Op #4
goanalysishard - Code AnalysisHard
Trace: Bit Op #5
goanalysishard - Code AnalysisHard
Trace: Bit Op #6
goanalysishard - Code AnalysisHard
Trace: Bit Op #7
goanalysishard - Code AnalysisHard
Trace: Bit Op #8
goanalysishard - Code AnalysisHard
Trace: Bit Op #9
goanalysishard - Code AnalysisHard
Trace: Bit Op #10
goanalysishard - Code AnalysisHard
Trace: Bit Op #11
goanalysishard - Code AnalysisHard
Trace: Bit Op #12
goanalysishard - Code AnalysisHard
Trace: Bit Op #13
goanalysishard - Code AnalysisHard
Trace: Bit Op #14
goanalysishard - Code AnalysisHard
Trace: Bit Op #15
goanalysishard - Code AnalysisHard
Trace: Bit Op #16
goanalysishard - Code AnalysisHard
Trace: Bit Op #17
goanalysishard - Code AnalysisHard
Trace: Bit Op #18
goanalysishard - Code AnalysisHard
Trace: Bit Op #19
goanalysishard - Code AnalysisHard
Trace: Bit Op #20
goanalysishard - Code AnalysisHard
Trace: Bit Op #21
goanalysishard - Code AnalysisHard
Trace: Bit Op #22
goanalysishard - Code AnalysisHard
Trace: Bit Op #23
goanalysishard - Code AnalysisHard
Trace: Bit Op #24
goanalysishard - Code AnalysisHard
Trace: Bit Op #25
goanalysishard - Code AnalysisHard
Trace: Bit Op #26
goanalysishard - Code AnalysisHard
Trace: Bit Op #27
goanalysishard - Code AnalysisHard
Trace: Bit Op #28
goanalysishard - Code AnalysisHard
Trace: Bit Op #29
goanalysishard - Code AnalysisHard
Trace: Bit Op #30
goanalysishard - Code AnalysisHard
Trace: Bit Op #31
goanalysishard - Code AnalysisHard
Trace: Bit Op #32
goanalysishard - Code AnalysisHard
Trace: Bit Op #33
goanalysishard - Code AnalysisHard
Trace: Bit Op #34
goanalysishard - Code AnalysisHard
Trace: Bit Op #35
goanalysishard - Code AnalysisHard
Trace: Bit Op #36
goanalysishard - Code AnalysisHard
Trace: Bit Op #37
goanalysishard - Code AnalysisHard
Trace: Bit Op #38
goanalysishard - Code AnalysisHard
Trace: Bit Op #39
goanalysishard - Code AnalysisHard
Trace: Bit Op #40
goanalysishard - Code AnalysisHard
Trace: Bit Op #41
goanalysishard - Multiple ChoiceHard
Go: Memory
gohard - Multiple ChoiceHard
Go: Goroutine Leak
gohard - Multiple ChoiceHard
Go: Channel Direction
gohard - Multiple ChoiceHard
Go: Nil Channel
gohard - Multiple ChoiceHard
Go: Closed Channel Receive
gohard - Multiple ChoiceHard
Go: Fan-Out
gohard - Multiple ChoiceHard
Go: Fan-In
gohard - Multiple ChoiceHard
Go: sync.Pool
gohard - Multiple ChoiceHard
Go: sync.Cond
gohard - Multiple ChoiceHard
Go: atomic Package
gohard - Multiple ChoiceHard
Go: Race Detector — False Positives
gohard - Multiple ChoiceHard
Go: reflect Package
gohard - Multiple ChoiceHard
Go: unsafe.Pointer
gohard - Multiple ChoiceHard
Go: cgo — Overhead
gohard - Multiple ChoiceHard
Go: Build Tags (h14)
gohard - Multiple ChoiceHard
Go: //go:generate
gohard - Multiple ChoiceHard
Go: Escape Analysis
gohard
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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.