leetcode 15. 三数之和

题目描述

代码：

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        sort(nums.begin(),nums.end());
        int len = nums.size();
        int left = 0;
        int right = 0;
        vector<vector<int>> res;
        for(int i = 0;i <len;i++){
            if(nums[i]>0)
                break;
            if(i>0 && nums[i-1] == nums[i])
                continue;
            left = i+1;
            right = len-1;
            while(left <right){
                if(nums[i]+nums[left]+nums[right] == 0){
                    while(nums[left] == nums[left+1]&&left+1<right)
                        left++;
                    while(nums[right] == nums[right-1]&&left<right-1)
                        right--;
                    res.push_back({nums[i],nums[left],nums[right]});
                    left++;
                    right--;
                }
                else if(nums[i]+nums[left]+nums[right] > 0)
                    right--;
                else
                    left++;
            }
        }
        return res;
    }
};