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?
本题可以用missing number的方法来做，因为数组里面除了某一个元素外，其余都出现两次，代码如下：
public class Solution {
public int singleNumber(int[] nums) {
int xor = 0;
for(int i=0;i<nums.length;i++){
xor = xor^nums[i];
}
return xor;
}
}