136. 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?

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;

    }

}