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# 326. Power of Three
class Solution(object):
def isPowerOfThree(self, n):
"""
the positive divisors of 3^19 are exactly the powers of 3
from 3^0 to 3^19. that's all powers of 3 in the possible range
here (signed 32-bit integer). so check whether the number is
positive and whether it divides 3^19
"""
return n > 0 == 3**19 % n
if __name__ == "__main__":
obj = Solution()
print(obj.isPowerOfThree(27))
print(obj.isPowerOfThree(0))
print(obj.isPowerOfThree(-1))
print(obj.isPowerOfThree(6561))
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