LeetCode 136 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).

分析：

跟4sum一样，利用排序的性质尝试所有可能，保证三个数的有序性。

public class Solution {    public int threeSumClosest(int[] num, int target) {        int min = Integer.MAX_VALUE;        int result = 0;        Arrays.sort(num);        for(int i=0; i<num.length-2; i++){            int j=i+1;            int k=num.length-1;            while(j<k){                int sum = num[i]+num[j]+num[k];                int diff = Math.abs(sum-target);                if(diff < min){                    min = diff;                    result = sum;                }                if(sum <= target)                    j++;                else                    k--;            }        }        return result;    }}