Single Number LeetCode java

Single Number
描述
Given an array of integers, every element appears twice except for one. Find that single one.
Note: Your algorithm should have a linear runtime complexity. Could you implement it without using
extra memory?
分析
异或，不仅能处理两次的情况，只要出现偶数次，都可以清零.

异或  x^x=0  ,    x^0=x

代码

1 // LeetCode, Single Number
2 class Solution {
3         public static int singleNumber(int A[]) {
4              for(int i=1;i<A.length;i++){
5                    A[i]^=A[i-1];
6              }
7              return A[A.length-1];
8 }