231 Power of Two
Given an integer, write a function to determine if it is a power of two.
The Idea: A number is a power of 2 if it has a single activated bit. E.g.
00000000000000001
00000000000000010
00000000000000100
...
10000000000000000
Complexity: O(1) time and space
class Solution:
def isPowerOfTwo(self, n):
"""
:type n: int
:rtype: bool
"""
if n <= 0:
return False
cur_power = 1
while cur_power <= n:
if cur_power == n:
return True
cur_power <<= 1
return False
Last modified 4yr ago