[LeeCode]Power of Two

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

My initial code:

 class Solution:
     # @param {integer} n
     # @return {boolean}
     def isPowerOfTwo(self, n):
         if n==0 :
             return False
         if n==1 or n==2:
             return True
         if n % 2 != 0:
             return False
         if n < 4 and n
         return self.isPowerOfTwo(n/2)

After google the internet, the best solution is:

class Solution:
    # @param {integer} n
    # @return {boolean}
    def isPowerOfTwo(self, n):
        if n<= 0 or n&(n-1) != 0:
            return False
        return True