Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

 

public class Solution {
    public int singleNumber(int[] nums) {
        if (nums == null || nums.length == 0) {
        	return 0;
        }
        int res = 0;
        for (int i = 0; i < nums.length; i++) {
			res ^= nums[i];
		}
        return res;
    }
}