136. Single Number

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

要求：线性时间，常量空间

异或：2个相同数异或为0,0与任意数异或还是等于原来的数。

public int singleNumber(int[] nums) {
        int result=0;
        for(int i=0;i<nums.length;i++)
            result=result^nums[i];
        return result;
    }