Power of Two

 1 public class Solution {
 2     public boolean isPowerOfTwo(int n) {
 3         if(n == 0) return false;
 4         if(n == 1) return true;
 5 
 6         if(n % 2 == 1) return false;
 7 
 8         return isPowerOfTwo(n / 2);
 9     }
10 }