Leet Code:Single Number

题目描述

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?

解法

利用位异或操作：a&a=0; a&0=a，异或操作符合交换律和结合律（参见c/c++位操作简介--移位、位与、位或、异或）。

代码

class Solution {public:    int singleNumber(int A[], int n) {        int res=A[0];        for(int i=1;i<n;++i)            res^=A[i];        return res;    }};

参考

http://www.cnblogs.com/lailailai/p/3681697.html