3Sum
Medium
Array
Two Pointers
Sorting
Given an integer array `nums`, return all the triplets `[nums[i], nums[j], nums[k]]` such that `i != j`, `i != k`, and `j != k`, and `nums[i] + nums[j] + nums[k] == 0`. Notice that the solution set must not contain duplicate triplets.
Example 1
Input: nums = [-1,0,1,2,-1,-4]
Output: [[-1,-1,2],[-1,0,1]]
Explanation: nums[0] + nums[1] + nums[2] = (-1) + 0 + 1 = 0. nums[1] + nums[2] + nums[4] = 0 + 1 + (-1) = 0. nums[0] + nums[3] + nums[4] = (-1) + 2 + (-1) = 0.
Example 2
Input: nums = [0,1,1]
Output: []
Explanation: The only possible triplet does not sum up to 0.
Example 3
Input: nums = [0,0,0]
Output: [[0,0,0]]

Constraints

  • •3 <= nums.length <= 3000
  • •-10⁵ <= nums[i] <= 10⁵
Time Complexity
O(n²)
Space Complexity
O(1)
14
Case 1
Input: [-1,0,1,2,-1,-4]
Expected: [[-1,-1,2],[-1,0,1]]
Case 2
Input: [0,1,1]
Expected: []
Case 3
Input: [0,0,0]
Expected: [[0,0,0]]