231 Power of Two

and

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

Example 1:

Input: 1
Output: true 
Explanation: 2^0 = 1
Example 2:

Input: 16
Output: true
Explanation: 2^4 = 16
Example 3:

Input: 218
Output: false

class Solution {
    public boolean isPowerOfTwo(int n) {
        if (n == 0) {
            return false;
        }
        if (n == 1) {
            return true;
        }
        if (n % 2 == 0) {
            return isPowerOfTwo(n / 2);
        }
        return false;
    }
}