Given an array of integers, every element appears twice except for one. Find that single one.
Analysis:
Use XOR operation.
Solution:
1 public class Solution { 2 public int singleNumber(int[] A) { 3 if (A.length==0) return -1; 4 int res = A[0]; 5 for (int i=1;i<A.length;i++) 6 res = res^A[i]; 7 return res; 8 9 } 10 }
原文：http://www.cnblogs.com/lishiblog/p/4179349.html