342. Power of Four
Đề Bài
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:
-231 <= n <= 231 - 1
Follow up: Could you solve it without loops/recursion?
Lời Giải
Python
0342-power-of-four.py
class Solution:
def isPowerOfFour(self, n: int) -> bool:
while n > 1:
if n % 4 != 0:
return False
n //= 4
return n == 1