326. Power of Three

Given an integer, write a function to determine if it is a power of three.

Example 1:

Input: 27
Output: true

Example 2:

Input: 0
Output: false

Example 3:

Input: 9
Output: true

Example 4:

Input: 45
Output: false

Follow up:
Could you do it without using any loop / recursion?

class Solution {
    public boolean isPowerOfThree(int n) {
        return Math.log10(n) / Math.log10(3) % 1 == 0; 
    }
}

真就一行啊

小数除以整数余数也是小数

0除以任何数余数都是0