Asked at

3Sum

Medium
VerifiedArrayTwo PointersSorting~25 min

Given an integer array nums, return all unique triplets [a, b, c] that sum to 0, using three distinct positions. The solution set must contain no duplicate triplets.

Sort, fix one element, then two-pointer the rest while skipping equal values to avoid duplicates. The input arrives as a single array nums.

Examples

in[-1, 0, 1, 2, -1, -4]
out[[-1, -1, 2], [-1, 0, 1]]

Both triplets sum to 0 and use distinct positions; no duplicates.

in[0, 1, 1]
out[]

No three values sum to 0.

Constraints

  • 3 ≤ nums.length ≤ 3000
  • -10⁵ ≤ nums[i] ≤ 10⁵
  • The triplets and their order may be returned in any order.

Get help

🔑

Sign in to solve

Sign in to write, run, and submit your solution — and to pick up where your iOS flow left off.