leetcode-16. 3Sum Closest

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https://leetcode.com/problems/3sum-closest/#/description
问题描述
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).

解题思路：
http://blog.csdn.net/u013275928/article/details/71440744
用到上一道题的思想，设立三个指针，与上一题不同这次是找与目标值最相近的一个数值，所以想到了求绝对值，但是指针移动时相同的值也需要考虑，所以值相等也不能将指针一直移动。注意到这几点，就不难将题解出。

代码如下：

public class Solution {    public int threeSumClosest(int[] nums, int target) {        Arrays.sort(nums);        int i=0;        int test=nums[0]+nums[1]+nums[nums.length-1];        while(i<nums.length-2)        {            int j=i+1;            int k=nums.length-1;            while(j<k)            {                int sum=nums[i]+nums[j]+nums[k];                if(sum<target) ++j;                if(sum>=target) k--;               if(Math.abs(sum-target) <Math.abs(test-target)   ) test=sum;            }                ++i;        }        return test;    }}

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