LeetCode OJ：Power of Two（2的幂）

 1 class Solution {
 2 public:
 3     bool isPowerOfTwo(int n) {
 4         if(n<=0) return false;
 5         bool isPower = false;
 6         for(int i = 1; i < n; i<<=1){
 7             if(!isPower && (i&n))
 8                 isPower = true;
 9             else if(isPower && (i&n)){
10                 return false;
11             }
12         }      
13         return true;
14     }
15 };