326. 3的幂 思路: 1.计算机中的数上界是 2^32,其中3的幂值中最大值是 3^19 2.判断 3^19 %n == 0 and n>0 class Solution: def isPowerOfThree(self, n: int) -> bool: return n>0 and 1162261467%n ==0