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two_sum.py — DevPrep

Easy#1 · Arrays

1def two_sum(nums, target):
2    seen = {}
3    for i, n in enumerate(nums):
4        if target - n in seen:
5            return [seen[target - n], i]
6        seen[n] = i
7    return []

All 47 tests passedruntime 64ms · O(n)

DevPrep AI1.2s

Solid one-pass hash map. You could rename seen to idx_by_value to make intent obvious in interviews.

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