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).

#include<vector>#include<cmath>#include<algorithm>#include<iostream>using namespace std;class Solution {    public:    int threeSumClosest(vector<int>& nums, int target) {        if(nums.size() < 3)        return 0;        sort(nums.begin(), nums.end());        int result = nums[0] + nums[1] + nums[2];        for(int index = 0; index < nums.size() - 2; index++)        {            int start = index + 1;            int end =  nums.size() - 1;            while(start < end)            {                int sum = nums[index] + nums[start] + nums[end];                if(sum > target)                end--;                else                start++;                if(abs(sum - target) < abs(result - target))                result = sum;            }        }        return result;    }};