翻译
给定一个有n个整数的数组S，是否存在三个元素a,b,c使得a+b+c=0?找出该数组中所有不重复的3个数，它们的和为0。备注：这三个元素必须是从小到大进行排序。结果中不能有重复的3个数。例如，给定数组S={–1 4}，一个结果集为：(-1, 0, 1)(-1, -1, 2)
原文
Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets .Note:Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤ c)The solution set must not contain duplicate triplets.For example, given array S = {–1 -4},A solution set is:(-1, 0, 1)(-1, -1, 2)
经典方法，可惜我并没有想到这样写……
class Solution {public:vector<vector<int>> threeSum(vector<int>& nums) {sort(nums.begin(), nums.end());vector<vector<int>> result;int len = nums.size();for (int current = 0; current < len – 2&&nums[current]<=0;current++){int front = current + 1, back = len – 1;while (front < back){if (nums[current] + nums[front] + nums[back] < 0)front++;else if (nums[current] + nums[front] + nums[back] > 0)back–;else{vector<int> v(3);v.push_back(nums[current]);v.push_back(nums[front]);v.push_back(nums[back]);result.push_back(v);v.clear();do {front++;} while (front < back&&nums[front – 1] == nums[front]);do {back–;} while (front < back&&nums[back + 1] == nums[back]);}}while (current < len – 2 && nums[current + 1] == nums[current])current++;}return result;}};
继续努力……
，青春不是年华，而是心境；青春不是桃面丹唇柔膝，
