标签：temp not blog tar tor push 双指针 pre cat
2017-10-04 16:30:13
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 in the array which gives the sum of zero.
Note: The solution set must not contain duplicate triplets.
For example, given array S = [-1, 0, 1, 2, -1, -4], A solution set is: [ [-1, 0, 1], [-1, -1, 2] ]
主要思路：先排序，然后利用双指针法，注意去重。有三处要去重。
1 class Solution { 2 public: 3 vector<vector<int>> threeSum(vector<int>& nums) { 4 //双指针法 5 vector<vector<int>> res; 6 vector<int> temp; 7 sort(nums.begin(),nums.end()); 8 //先排序，用于去重。 9 for(int i=0;i<nums.size();i++){ 10 int front=i+1,back=nums.size()-1; 11 int target=-nums[i]; 12 while(front<back){ 13 if(target<nums[front]+nums[back]) back--; 14 else if(target>nums[front]+nums[back]) front++; 15 else{ 16 temp.push_back(nums[i]); 17 temp.push_back(nums[front]); 18 temp.push_back(nums[back]); 19 res.push_back(temp); 20 21 while(front<back&&nums[front]==temp[1]) front++; 22 while(front<back&&nums[back]==temp[2]) back--; 23 temp.clear(); 24 } 25 } 26 while(i+1<nums.size()&&nums[i]==nums[i+1]) i++; 27 } 28 return res; 29 } 30 };
标签：temp not blog tar tor push 双指针 pre cat
原文地址：http://www.cnblogs.com/wsw-seu/p/7625797.html
