Given an integer n, return true if it is a power of four. Otherwise, return false.
An integer n is a power of four, if there exists an integer x such that n == 4x.
Example 1:
Input: n = 16
Output: true
Example 2:
Input: n = 5
Output: false
Example 3:
Input: n = 1
Output: true
Constraints:
-2^31 <= n <= 2^31 - 1
Follow up: Could you solve it without loops/recursion?
class Solution:
def isPowerOfFour(self, n: int) -> bool:
if n <= 0:
return False
while n > 1:
if n%4 == 0:
n //= 4
continue
else:
return False
return True
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