Marathon: a parser for a real grammar
Hand-roll a recursive-descent parser for a small but real config grammar. Errors must point at the column. No parser generators.
Contract
twoSum(input: any) → any
Return the indices, not the values. Order matters.
Visible tests
- in: [2, 7, 11, 15], target: 9→ [0, 1]
- in: [3, 2, 4], target: 6→ [1, 2]
- in: [3, 3], target: 6→ [0, 1]
+ 7 hidden tests fire on submit
Step in
Current Codigami · 1:42 by @reverie
Your best · 1:58
Break it for +12 Elo. Fall short for −3.
Same problem. Two ways to play. Both rank on the same Elo.
What this trial is
Hand-roll a recursive-descent parser for a small but real config grammar. Errors must point at the column. No parser generators.
Long-form trial — par ~40 minutes. Designed for a full session; the tape itself is the artifact, and peers will scrub through it.
Elo upside if you nail it
Solid run
+22 to +44
Top run
+60+
Medal line
diamond
Marathon trials. Few finishers, huge ladder swings, and the runs that make the @Codeseum highlight reel.
Solo Elo · MARK ÷ 100 vs field 2100, K-32. Codesport duel wins multiply by ×1.25, losses by ×0.40.
Trial leaderboard · ALGO-008
Best runs on this trial.
Composite = MARK · 60% + ROOM · 40%. Top 15% earn Bronze, top 5% Silver, top 1% Gold.
Top 15% on this trial earns Bronze; top 5% Silver; top 1% Gold. Trial trophies are per-trial visual rewards; the Elo ladder (Demi Coder → Master Coder) is the credential.
@Codeseum on YouTube
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