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 min=INT_MAX;int ret;for(int i=0;i<nums.size();i++){int j=i+1;int k=nums.size()-1;while(j<k){int sum=nums[i]+nums[j]+nums[k];int dif=abs(sum-target);if(dif<min){min=dif;ret=sum;}if(dif==0)return target;else if(sum>target)k--;elsej++;}}return ret;}};
原文：http://www.cnblogs.com/zhoudayang/p/5043019.html