class Solution {

public:

    int threeSumClosest(vector<int>& nums, int target) {

        sort(nums.begin(),nums.end());

       

        int len = nums.size();

        int ans = 0x3FFFFFFF;

        int res = 0;

        for(int i = 0 ; i < len ; i ++)

        {

            int left = i + 1;

            int right = len - 1;

            while(left < right)

            {

                int key = nums[left] + nums[right] + nums[i];

                if( key < target ){

                    left ++;

                }else if( key > target ){

                    right --;

                }else

                    return target;

                int fc = abs(key-target);

                if( fc < ans )

                {

                    ans = fc;

                    res = key;

                }

            }

           

        }

        return res;

       

    }

};