728. Self Dividing Numbers

Description

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.

Solution

Iterative

class Solution {
    public List<Integer> selfDividingNumbers(int left, int right) {
        List<Integer> result = new ArrayList<>();
        
        for (int i = left; i <= right; ++i) {
            if (isSelfDividingNumber(i)) {
                result.add(i);
            }
        }
        
        return result;
    }
    
    public boolean isSelfDividingNumber(int i) {
        int j = i;
        
        while (j > 0) {
            if (j % 10 == 0 || i % (j % 10) != 0) {
                break;
            }
            j /= 10;
        }

        return j == 0;
    }
}