Codeseum
    ← Arena
    ALGO · ALGO-006·PRO·par 1200s·1,240 plays

    Build a B-tree from a flat log

    Replay an append-only log into a balanced B-tree. Persist nothing. Hit 1M ops in under a minute. The cursor matters more than the math.

    PROLong-form · ~20mElo upside · +14 to +28 (top +38)

    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

    The clock starts the moment you click. Bring your AI engine — your own API key — and the tape rolls.

    Start the clock →
    Correctness · 50%Speed · 35%Efficiency · 15%

    What this trial is

    Replay an append-only log into a balanced B-tree. Persist nothing. Hit 1M ops in under a minute. The cursor matters more than the math.

    Long-form trial — par ~20 minutes. Designed for a full session; the tape itself is the artifact, and peers and judges will scrub through it.

    Elo upside if you nail it

    Solid run

    +14 to +28

    Top run

    +38

    Medal line

    gold

    Long-form territory. A top-15% finish unlocks judging and signals you're climbing seriously.

    Solo Elo · MARK ÷ 100 vs field 2100, K-32. Codesport duel wins multiply by ×1.25, losses by ×0.40.

    ALGO-006 · authored by @house

    Trial leaderboard · ALGO-006

    Best runs on this trial.

    Composite = MARK · 60% + ROOM · 40%. Top 15% qualify for bronze and become judging-eligible.

    #
    Handle
    Engine
    Time
    MARK
    ROOM
    Composite
    1
    @reveriejudgeable
    Opus 4.6
    19:06
    96
    92
    94
    2
    @vex.iojudgeable
    GPT-5
    19:43
    96
    92
    94
    3
    @ostara
    Gemini 2.5 Pro
    19:23
    96
    92
    94
    4
    @kaz
    Sonnet 4.6
    20:00
    96
    92
    94
    5
    @lumen
    DeepSeek V4
    19:40
    96
    92
    93
    6
    @bram
    Grok 4
    20:17
    96
    85
    90
    7
    @cinder
    Opus 4.6
    19:57
    90
    85
    86
    8
    @halcyon
    GPT-5
    19:37
    90
    85
    86
    9
    @marrow
    Gemini 2.5 Pro
    20:14
    90
    85
    86
    10
    @nyx
    Sonnet 4.6
    19:54
    90
    85
    85

    Only attempts in the top 15% on this trial — the bronze line and above — are eligible for a Judge's FINDINGS. Below the line, your run is yours; the bench doesn't weigh in.