Leetcode Problem 326 Power of Three.txt

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?


Hint to solve: Recursive, iterative and logarithmic ways
x = 3^i
i = log(x)/log(3)
if i is an integer then the given number is divisible by power of three.


class Solution:
    
    def recursive(self, n) -> bool:
        return n > 0 and (n == 1 or (n%3 == 0 and self.recursive(n/3)))
    
    def iterative(self, n) -> bool:
        while(n > 0):
            if n == 1:
                return True
            if n%3 == 0:
                n = n/3
            else:
                return False
        return False
    
    def logarithm(self, n)-> bool:
        if n > 0:
            return (math.log10(n)/math.log10(3)) % 1 == 0;
        else:
            return False
        
    def isPowerOfThree(self, n: int) -> bool:
        #return self.recursive(n)
        #return self.iterative(n)
        return self.logarithm(n)