LeetCode(16)题解--3Sum Closest

https://leetcode.com/problems/3sum-closest/

题目：

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).

思路：

和上一道差不多，主要还是有序数组里两个flag移动。

AC代码：

class Solution {
public:
int threeSumClosest(vector<int>& nums, int target) {
int res,t,j,k,lowerbound=INT_MAX,n=nums.size();
sort(nums.begin(),nums.end());
for(int i=0;i<n-2;i++){
t=target-nums[i];
j=i+1;
k=n-1;
while(j<k){
if(abs(nums[j]+nums[k]-t)<lowerbound){
res=nums[i]+nums[j]+nums[k];
lowerbound=abs(nums[j]+nums[k]-t);
}
if(nums[j]+nums[k]<t)
j++;
else
k--;
}
}
return res;
}
};