public List<Integer> addToArrayForm(int[] num, int k) {

List<Integer> result = new ArrayList<>();

int sum;

for (int i = num.length - 1, carry = 0 ; i >= 0 || carry > 0 || k > 0 ; i--, k /= 10) {

sum = get(num, i) + carry + k % 10;

result.add(sum % 10);

carry = sum / 10;

}

Collections.reverse(result);

return result;

}

private int get(int[] array, int index) {

if (index < 0) return 0;

return array[index];

}