[231] Power of Two

https://leetcode.com/problems/power-of-two/description/

• algorithms
• Easy (41.27%)
• Source Code: 231.power-of-two.py
• Total Accepted: 221.3K
• Total Submissions: 529.4K
• Testcase Example: '1'

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

class Solution(object):
    def isPowerOfTwo(self, n):
        """
        :type n: int
        :rtype: bool
        """
        if n & n-1: return False

        while n > 1:
            n = n >> 1

        return True if n == 1 else False