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Problem

Two Sum

LeetCode #1Easy
Unsorted · find a pair adding to target

Given an array of integers and a target, return the indices of the two numbers that add up to the target. Exactly one solution exists and you may not reuse an element.

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step 1 / 18
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Brute force
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1given arr, target
2for i ← 0 to n − 2:
3    for j ← i + 1 to n − 1:
4        if arr[i] + arr[j] == target:
5            return (i, j)
6return none
state
  • target10

line 1Find two indices i ≠ j with arr[i] + arr[j] = 10. The array is NOT sorted, so two-pointers won't work directly.