Single Number

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?

public class Solution {    public int singleNumber(int[] A) {        int n=A[0];        for(int i=1;i<A.length;i++){            n^=A[i];        }        return n;    }}

主要运用到了异或运算的性质。