[LeetCode] 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> &num, int target) {        sort(num.begin(), num.end());        int result = 0x6fffffff;        for(int i = 0; i < num.size(); i++)        {            int j = i+1;            int k = num.size()-1;            while(j < k)            {                int sum = num[i] + num[j] + num[k];                if(abs(sum-target) < abs(result-target))                    result = sum;                if(result == target)                    return result;                if(sum > target)                    k--;                else                    j++;            }        }        return result;    }};