power_of_3.java

public class Solution {
    public boolean isPowerOfThree(int n) {
        // special case
        if(n == 0) return false;
        while(n != 1) {
            // check if n can be divided by 3, return false if not
            if(n%3 != 0) return false;
            // take the result as input of next check until it's 1 which means n is power of 3
            n = n/3;
        }
        return true;
    }
}