Array + two points leetcode.15-3Sum

题面

Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.

Note: The solution set must not contain duplicate triplets.

给定数组，找出其中不重复的三个和为0的元素集合。

样例

1. Given array nums = [-1, 0, 1, 2, -1, -4],
solution set is:
[
  [-1, 0, 1],
  [-1, -1, 2]
]

2. Given array nums = [0， 0， 0],
solution set is:
[
  [0, 0, 0]
]
note: this example may cause something wrong!
(heap overflow? Need you to try it.)

思路

按照我以往的傻瓜思路，暴力来解决的话，time complexity will be O(n³)，that's fool.

这里参考了（抄）一个简单易于理解的solution