LeetCode - 728. Self Dividing Numbers

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.

class Solution {
    public List<Integer> selfDividingNumbers(int left, int right) {
        left = left < 1 ? 1 : left;
        List<Integer> list = new ArrayList<Integer>();
        if (right < left)
            return list;
        for (int i=left; i<=right; i++)
            if (isSelf(i))
                list.add(i);
        return list;
    }
    private boolean isSelf(int n) {
        String ns = String.valueOf(n);
        for (int i=0; i<ns.length(); i++) {
            int nsn = ns.charAt(i)-'0';
            if (nsn == 0 || (n % nsn) != 0)
                return false;
        }
        return true;
    }
}