class Solution {public:    int threeSumClosest(vector<int> &num, int target) {        int ret = 99999999999;        std::sort(num.begin(), num.end());        for (int i0 = 0; i0 < num.size() - 2; i0++)        {            int i1 = i0 + 1, i2 = num.size() - 1;            while (i1 < i2)            {                int curr = num[i0] + num[i1] + num[i2];                if (curr == target)            return target;                else if (curr < target)        i1 ++;                else if (curr > target)        i2 --;                if (abs(curr - target) < abs(ret - target))                    ret = curr;            }        }        return ret;    }};