leetcode-3Sum Closest

Difficulty: Medium

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) {
        sort(nums.begin(),nums.end());
        int size=nums.size();
        int mingap=INT_MAX;
        for(int i=0;i<size-2;++i){
            int begin=i+1;
            int end=size-1;
            
            while(begin<end){
                int temp=nums[i]+nums[begin]+nums[end]-target;
                if(temp==0)
                    return target;
                else if(temp<0)
                    ++begin;
                else
                    --end;
                if(abs(temp)<abs(mingap))
                    mingap=temp;
            }
        }
        return target+mingap;
    }
};