Power of Three(leetcode326)

Given an integer, write a function to determine if it is a power of three.

Example 1:

Input: 27
Output: true

Example 2:

Input: 0
Output: false

Example 3:

Input: 9
Output: true

Example 4:

Input: 45
Output: false

Follow up:
Could you do it without using any loop / recursion?

public static List<Long> list = null;

    static{
        list = new ArrayList<>();
        for(int i= 0;i<Integer.MAX_VALUE;i++){
            Double value = Math.pow((double)3,(double)i);
            if(value.longValue() > (long)Integer.MAX_VALUE){
                  break;
            }
            list.add(value.longValue());
        }
    }

    //發現先把數據取出來 比對一下 妥妥的  可是用了loop 哎
    public static boolean isPowerOfThree(int n) {
           return list.contains((long)n);
    }


    //看看大神的表演 原來這樣就能夠啦
    public static boolean isPowerOfThree2(int n) {
        // 1162261467 is 3^19,  3^20 is bigger than int
        return ( n>0 &&  1162261467%n==0);
    }

    //好吧 都用上公式啦
    public static boolean isPowerOfThree3(int n) {
        return (Math.log10(n) / Math.log10(3)) % 1 == 0;
    }


    public static void main(String[] args) {
        System.out.println(isPowerOfThree3(9));
        System.out.println(isPowerOfThree3(27));
        System.out.println(isPowerOfThree3(0));
        System.out.println(isPowerOfThree3(45));

             //這裏會是什麼
//          Integer a = 6;
//          Long b = 6L;
//          System.out.println(a.equals(b));

    }

git：https://github.com/woshiyexinjie/leetcode-xin