Code Challenge — Live IDE
Real tasks · auto-grading · deterministic test suite
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solution.js
JavaScript
14:59
Live
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export function twoSum(nums, target) {
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const map = new Map();
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for (let i = 0; i < nums.length; i++) {
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const need = target - nums[i];
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if (map.has(need)) return [map.get(need), i];
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map.set(nums[i], i);
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}
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return null;
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}
Test suite
2/3 passed
- Returns [0,1] for nums=[2,7,11,15], target=9
- Returns null when no solution exists
- Handles duplicate entries correctly
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