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;

 
    }
};