Power of Three

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:

-2^31 <= n <= 2^31 - 1

Follow up:

Could you solve it without loops/recursion?

Code

C++

class Solution
{
public:
    bool isPowerOfThree(int n)
    {

        if (n <= 0)
            return false;

        int cur = 1;

        while (cur <= n)
        {
            if (n % cur == 0 && cur == n)
                return true;
            cur = cur * 3;
        }
        // cur>n
        return false;
    }
};