leetcode Power of Two

题目连接

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

Power of Two

Description

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

水一发python。。

class Solution(object):
    def isPowerOfTwo(self, n):
    	shift = 1
    	if n == 1 or n == 2:
    		return True
    	while shift < n:
    		shift <<= 1
    	return shift == n