326 Power of Three - Easy

Problem:

Given an integer n, return true if it is a power of three. Otherwise, return false.

An integer n is a power of three, if there exists an integer x such that n == 3x.

Example 1:

Input: n = 27 Output: true Explanation: 27 = 33

Example 2:

Input: n = 0 Output: false Explanation: There is no x where 3x = 0.

Example 3:

Input: n = -1 Output: false Explanation: There is no x where 3x = (-1).

Constraints:

• -231 <= n <= 231 - 1

Follow up: Could you solve it without loops/recursion?

Problem Analysis:

• use log; be careful of floating point issue
• or while loop

Solutions:

class Solution:
    def isPowerOfThree(self, n: int) -> bool:
        return n > 0 and int(math.log10(n) / math.log10(3)) == (math.log10(n) / math.log10(3))

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