【LeetCode OJ】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 result = 0;
		for(int i = 0, len = A.length; i < len; ++i){
			result = result^A[i];
		}
		return result;  
    }
}