The array-form of an integer `num` is an array representing its digits in left to right order.

- For example, for `num = 1321`, the array form is `[1,3,2,1]`.

Given `num`, the array-form of an integer, and an integer `k`, return the array-form of the integer `num + k`.

Example 1:

    Input: num = [1,2,0,0], k = 34
    Output: [1,2,3,4]
    Explanation: 1200 + 34 = 1234

Example 2:

    Input: num = [2,7,4], k = 181
    Output: [4,5,5]
    Explanation: 274 + 181 = 455

Example 3:

    Input: num = [2,1,5], k = 806
    Output: [1,0,2,1]
    Explanation: 215 + 806 = 1021

Constraints:

- `1 <= num.length <= 104`
- `0 <= num[i] <= 9`
- `num` does not contain any leading zeros except for the zero itself.
- `1 <= k <= 104`