231. Power of Two

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

Example 1:

Input: 1
Output: true 
Explanation: 20 = 1

Example 2:

Input: 16
Output: true
Explanation: 24 = 16

Example 3:

Input: 218
Output: false

Python

 
class Solution(object):
    def isPowerOfTwo(self, n):
        """
        :type n: int
        :rtype: bool
        """
        if n < 0:
            return False
        a = str(bin(n)).replace("b", "")
        result = 0
        for i in a:
            result += int(i)
        return True if result == 1 else False