326. Power of Three

Posted on Edited on In

326. Power of Three

Description

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 == 3^x.

Example 1:

1
2
3
Input: n = 27
Output: true
Explanation: 27 = 3^3

Example 2:

1
2
3
Input: n = 0
Output: false
Explanation: There is no x where 3^x = 0.

Example 3:

1
2
3
Input: n = -1
Output: false
Explanation: There is no x where 3^x = (-1).

Constraints:

  • -2^31 <= n <= 2^31 - 1

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

Hints/Notes

Solution

Language: C++

1
2
3
4
5
6
7
8
9
10
11
12
class Solution {
public:
    bool isPowerOfThree(int n) {
        if (n <= 0) {
            return false;
        }
        while (n % 3 == 0) {
            n /= 3;
        }
        return n == 1;
    }
};