題目

Given an array?S?of?n?integers, are there elements?a,?b,?c?in?S?such that?a?+?b?+?c?= 0? Find all unique triplets in the array which gives the sum of zero.

Note:

• Elements in a triplet (a,b,c) must be in non-descending order. (ie,?a?≤?b?≤?c)
• The solution set must not contain duplicate triplets.

For example, given array S = {-1 0 1 2 -1 -4},A solution set is:(-1, 0, 1)(-1, -1, 2)

代碼

public class Solution {public List<List<Integer>> threeSum(int[] num) {Arrays.sort(num);int a,b,c;HashSet<List<Integer>> hs=new HashSet();for(int i=0;i<=num.length-3;i++){a=num[i];for(int m=i+1,n=num.length-1; m<n;){b=num[m];c=num[n];if(-a==(b+c)){List<Integer> ls=new ArrayList<Integer>();ls.add(a);ls.add(b);ls.add(c);hs.add(ls);n--;m++;}else if(-a>(b+c)){m++;}else{n--;}}}List<List<Integer>> result=new ArrayList(hs);return result; }}

代碼下載：https://github.com/jimenbian/GarvinLeetCode

/********************************

* 本文來自博客 ?“李博Garvin“

* 轉(zhuǎn)載請標明出處:http://blog.csdn.net/buptgshengod

******************************************/

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