## 3Sum Closest

### 描述

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).

### 代码

// 3Sum Closest
// 先排序，然后左右夹逼
// Time Complexity: O(n^2), Space Complexity: O(1)
public class Solution {
public int threeSumClosest(int[] nums, int target) {
int result = 0;
int minGap = Integer.MAX_VALUE;
Arrays.sort(nums);

for (int i = 0; i < nums.length - 1; ++i) {
int j = i + 1;
int k = nums.length - 1;

while(j < k) {
final int sum = nums[i] + nums[j] + nums[k];
final int gap = Math.abs(sum - target);
if (gap < minGap) {
result = sum;
minGap = gap;
}

if (sum < target) ++j;
else              --k;
}
}
return result;
}
}