Java [Leetcode 326]Power of Three

题目描述：

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

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

解题思路：

对给定的数求以3为底的对数，然后再将结果用于3的次幂，看是否与原来的数相同。

代码如下：

public class Solution {
    public boolean isPowerOfThree(int n) {
        return n <= 0 ? false : n == Math.pow(3, Math.round(Math.log(n) / Math.log(3)));
    }
}