[LeetCode 15] 3Sum

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        sort(nums.begin(),nums.end());
        vector<vector<int>> res;
        for(int i=0;i<nums.size();i++)
        {
            int target=-nums[i];
            int front=i+1;
            int back=nums.size()-1;
            while(front<back)
            {
                int sum=nums[front]+nums[back];
                if(sum>target)
                {
                    back--;
                }
                else if(sum<target)
                {
                    front++;
                }
                else
                {
                    vector<int> temp(3,0);
                    temp[0]=nums[i];
                    temp[1]=nums[front];
                    temp[2]=nums[back];
                    res.push_back(temp);
                    while(front<back&&nums[front]==temp[1]) front++;
                    while(front<back&&nums[back]==temp[2]) back--;
                }
            }
            while(i+1<nums.size()&&nums[i+1]==nums[i]) i++;
        }
        return res;



    }
};