LeetCode-16. 最接近的三数之和（3Sum Closest）

双指针加排序

class Solution {
public:
    vector<vector<int>> threeSum(vector<int>& nums) {
        vector<vector<int>> res;
        sort(nums.begin(), nums.end());
        int len = nums.size();
        if(len < 3 || nums[0] > 0 || nums[len - 1] < 0){
        	return res;
        }

    	for(int i = 0; i < len; i++) {
    		if(nums[i] > 0){
    			break;
    		}
    		if(i > 0 && nums[i] == nums[i - 1]){
    			continue;
    		}
    		int l = i + 1, r = len - 1;
    		while(l < r) {
    			int result = nums[l] + nums[i] + nums[r];
    			if(result == 0) {
    				vector<int> v={nums[i], nums[l], nums[r]};
    				res.push_back(v);
    				while(l < r && nums[l] == nums[++l]);
    				while(l < r && nums[r] == nums[--r]);
    			}else if(result > 0) {
    				r--;
    			}else if(result < 0) {
    				l++;
    			}
    		}
    	}
        return res;
    }
};

题目链接：https://leetcode-cn.com/problems/3sum-closest/submissions/