[LeetCode]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) {
// Note: The Solution object is instantiated only once and is reused by each test case.
int result = 0;
if(A.length == 0)
return 0;
for(int i = 0;i<A.length;i++){
result ^= A[i];
}
return result;
}
}