Problem 326: Power of Three

https://leetcode.com/problems/power-of-three/#/description

思路

• $n = 3 ^ m$ 等价于 $log(n) = m * log(3)$

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

public class Solution {
    public boolean isPowerOfThree(int n) {
        if (n > 1) {
            while (n % 3 == 0) n /= 3;
        }

        return n == 1;
    }
}