# 342. Power of Four
"""
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 == 4^x'
"""
class Solution(object):
def isPowerOfFour(self, n):
return n > 0 and n.bit_count() == 1 and (n - 1) % 3 == 0
if __name__ == "__main__":
obj = Solution()
print(obj.isPowerOfFour(16)) # expect: True
print(obj.isPowerOfFour(5)) # expect: False
print(obj.isPowerOfFour(1)) # expect: True
