Problem Description

Given an integer array nums, return all the triplets [nums[i], nums[j], nums[k]] such that i != ji != k, and j != k, and nums[i] + nums[j] + nums[k] == 0.

Notice that the solution set must not contain duplicate triplets.

Examples

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.
The distinct triplets are [-1,0,1] and [-1,-1,2].
Notice that the order of the output and the order of the triplets does not matter.

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]]
Explanation: The only possible triplet sums up to 0.

Constraints:

解析

給定一個整數陣列 nums

要求寫一個演算法找在所有在 nums 中3個和= 0 數字的所有不重複複組合

已知目標是找到 i, j , k , i < j < k , 使得 nums[i] + nums[j] + nums[k] =0

可以注意到 當 nums[j] 確定時, nums[i] + nums[k] 只能 - nums[j]

所以可透過 類似 two sum 的作法