LeetCode728 Self Dividing Numbers

题目：

       A self-dividing number is a number that is divisible by every digit it contains.

       For example, 128 is a self-dividing number because 128 % 1 == 0, 128 % 2 == 0, and 128 % 8 == 0.

       Also, a self-dividing number is not allowed to contain the digit zero.

       Given a lower and upper number bound, output a list of every possible self dividing number, including the bounds if possible.

       Example 1:

              Input: left = 1, right = 22

              Output: [1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, 22]

       Note:

       The boundaries of each input argument are 1 <= left <= right <= 10000.

public class SelfDividingNumbers {
    public static List<Integer> selfDividingNumbers(int left, int right) {
        List<Integer> resultList = new ArrayList<>();

        if (left < 1){
            resultList.add(0);
            return resultList;
        }

        for (int num = left; num <= right ; num++) {
            if (selfDividing(num))
                resultList.add(num);
        }
        return resultList;
    }

    public static boolean selfDividing(int num){
        int x = num;

        while (x > 0){
            int y = x % 10;

            if (y == 0){
                return false;
            }
            if (num % y != 0){
                return false;
            }

            x = x / 10;
        }

        return true;
    }

    public static void main(String[] args) {
        System.out.println(selfDividingNumbers(1,22).toString());
    }
}