231. Power of Two

Problem Statement :

Given an integer n, return true if it is a power of two. Otherwise, return false. An integer n is a power of two, if there exists an integer x such that n == 2x.

Examples :

Example 1

Input: n = 1
Output: true
Explanation: 20 = 1

Example 2

Input: n = 3
Output: false

Constrains :

-231 <= n <= 231 - 1

Solution (Py3) :

  class Solution:
    def isPowerOfTwo(self, n: int) -> bool:
        if n == 1:
            return True 
        elif n<=0 or n%2 != 0:
            return False
        return self.isPowerOfTwo(n//2)