LeetCode----326. Power of Three(Java)

package isPowerOfThree326;
/*
 Given an integer, write a function to determine if it is a power of three.
 */
public class Solution {
    /*
    //题目理解错误，理解成3次开方
    public static boolean isPowerOfThree(int n) {
        if (n==1)
            return true;
        else{
            for(int i=2;i<=Math.sqrt(n);i++){
                if(n%i==0){
                    n=n/i;
                    if(n%i==0){
                        n=n/i;
                        if (n%i==0){
                            n=n/i;
                            return isPowerOfThree(n);
                        }    
                        else
                            return false;
                    }
                    return false;
                }
            }
            return false;
        }
    }
    */
    public static boolean isPowerOfThree(int n){
        if (n==1)
            return true;
        else if (n==0)
            return false;
        else if (n%3==0){
            n=n/3;
            return isPowerOfThree(n);
        }
        else
            return false;
            
            
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println(isPowerOfThree(-3));
    }

}