algorythms
Two Pointers
LC #15Medium

3Sum

Two Pointers
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Problem

Find all unique triplets in an array that sum to zero.

arraytwo-pointerssorting

Constraints

  • 3 ≤ n ≤ 3000
  • -10⁵ ≤ nums[i] ≤ 10⁵
  • Output must not contain duplicate triplets

Example

Inputnums = [-1, 0, 1, 2, -1, -4]
Output[[-1, -1, 2], [-1, 0, 1]]
Why

Two unique triplets sum to zero; duplicates must be excluded

Hints — reveal one at a time