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@ostara's tape

CRAFT·2:18.4·Engine · Claude Opus 4.6·Submitted 2d ago· Top 15% · judge-eligible

Provisional · seat locked. Record is locked for 48h after being set. During the lock, only a ≥8% improvement takes the seat. After, any faster time wins.

32h 30m lock left

youtube · @Codeseum · CRAFT-008

MARK

AI · auto-graded

ROOM

Peers · 47 votes

FINDINGS

Judge · @house

The three scores stand on their own — none rewrite the others. Only the judge's findings move overall elo, and only on top-15% attempts.

Submitted code · solve.js

tests · 12 / 12

function twoSum(nums, target) {
  const seen = new Map();
  for (let i = 0; i < nums.length; i++) {
    const need = target - nums[i];
    if (seen.has(need)) return [seen.get(need), i];
    seen.set(nums[i], i);
  }
  return [];
}

Engine transcript · 4 turns · Opus 4.6

@ostara

I have a brute-force two-sum at O(n²). Suggest a better approach without writing the code.

Opus 4.6

Use a hash map keyed by complement. One pass, O(n).

@ostara

Edge case for duplicates?

Opus 4.6

Set the index after the lookup, not before. The current index can pair with an earlier duplicate.