leetcode——16——3Sum Closest

Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution.

For example, given array S = {-1 2 1 -4}, and target = 1. The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).

class Solution {public:    int threeSumClosest(vector<int>& nums, int target) {                int size = nums.size();        sort(nums.begin(), nums.end());        int closest = INT_MAX;        int closestSum = 0;        for(int i = 0; i < size; i ++)        {                        int j = i + 1;            int k = size - 1;            while(j < k)            {                int sum = nums[i] + nums[j] + nums[k];                if(abs(sum - target) < closest)                {                    closest = abs(sum - target);                    closestSum = sum;                                                       }                if(sum < target)                {                    j ++;                                    }                else                {                    k --;                                    }            }        }        return closestSum;     }};