标签：des style blog io color ar for sp div
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:
For example, given array S = {-1 0 1 2 -1 -4},
A solution set is:
(-1, 0, 1)
(-1, -1, 2)
Solution:
1 public class Solution { 2 public List<List<Integer>> threeSum(int[] num) { 3 List<List<Integer>> result = new ArrayList<List<Integer>>(); 4 if (num.length < 3) 5 return result; 6 Arrays.sort(num); 7 for (int i = 0; i < num.length - 2; ++i) { 8 if (i > 0 && num[i] == num[i - 1]) 9 continue; 10 int a = num[i]; 11 int low = i + 1; 12 int high = num.length - 1; 13 while (low < high) { 14 if (-a == num[low] + num[high]) { 15 List<Integer> temp = new ArrayList<Integer>(); 16 temp.add(a); 17 temp.add(num[low]); 18 temp.add(num[high]); 19 result.add(temp); 20 low++; 21 high--; 22 while (low < high && num[low] == num[low - 1]) 23 low++; 24 while (low < high && num[high] == num[high + 1]) 25 high--; 26 } else if (-a > num[low] + num[high]) 27 low++; 28 else 29 high--; 30 } 31 } 32 return result; 33 } 34 }
注意：如果current value==previous value，需要跳过当前值。
标签：des style blog io color ar for sp div
原文地址：http://www.cnblogs.com/Phoebe815/p/4066302.html
