Given an integer n, return true if it is a power of two. Otherwise, return false.
An integer n is a power of two, if there exists an integer x such that n == 2x.
Example 1:
Input: n = 1
Output: true
Explanation: 20 = 1
Example 2:
Input: n = 16
Output: true
Explanation: 24 = 16
Example 3:
Input: n = 3
Output: false
Constraints:
-
-231 <= n <= 231 - 1
Follow up: Could you solve it without loops/recursion?SOLUTION:
class Solution:
def isPowerOfTwo(self, n: int) -> bool:
if n <= 0:
return False
if n == 1:
return True
return not (n & 1) and self.isPowerOfTwo(n >> 1)
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