LeetCode解题报告--3Sum Closest

题目：与3数和最接近的和
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).

原题链接地址：https://leetcode.com/problems/3sum-closest/
分析：题意要求从给定数组找出和与目标数target最接近的triplet的和，该题与3Sum问题相关，可以参考一下。具体解题思想与3Sum相似。直接贴源码：

java代码（accepted)

public class Solution {    public List<List<Integer>> threeSum(int[] nums) {        List<List<Integer>> list = new ArrayList<List<Integer>>();        HashSet<List<Integer>> elementSet = new HashSet<List<Integer>>();        int sum = 0;        Arrays.sort(nums);        for (int i = 0; i < nums.length - 2; i++) {            int left = i + 1;            int right = nums.length - 1;            while (left < right) {                sum = nums[i] + nums[left] + nums[right];                if(sum == 0){                    List<Integer> element = new ArrayList<Integer>();                    element.add(nums[i]);                    element.add(nums[left]);                    element.add(nums[right]);                    if(!elementSet.contains(element)){                        list.add(element);                        elementSet.add(element);                    }                    left ++;                    right --;                }else if(sum < 0){                    left ++;                }else{                    right --;                }            }        }        return list;    }}

相关代码放在个人github:https://github.com/gannyee/LeetCode/tree/master/src