LeetCode OJ：Power of Two（2的幂）

Given an integer, write a function to determine if it is a power of two.

看一个数是不是2的幂，代码如下：

class Solution {
public:
    bool isPowerOfTwo(int n) {
        if(n<=0) return false;
        bool isPower = false;
        for(int i = 1; i < n; i<<=1){
            if(!isPower && (i&n))
                isPower = true;
            else if(isPower && (i&n)){
                return false;
            }
        }      
        return true;
    }
};