Expand Each Positive Integer into Its Ordered Decimal Digits
Company: Google
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Replace every positive number in `nums` by its decimal digits, from most significant to least significant. Concatenate these digit sequences in the original array order and return the resulting integer array.
```cpp
class Solution {
public:
vector<int> separateDigits(vector<int>& nums);
};
```
### Examples
**Example 1:**
```text
Input: nums = [20,105]
Output: [2,0,1,0,5]
Explanation: Internal zero digits are retained, and 20 precedes105.
```
**Example 2:**
```text
Input: nums = [9,4]
Output: [9,4]
Explanation: Each one-digit number contributes itself.
```
### Constraints
- `1 <= nums.length <= 1000`.
- `1 <= nums[i] <= 100000`.
### Clarifying Questions
- Is the array order preserved? Yes.
- Is each number's digit order preserved? Yes, from most significant to least significant.
- Are internal zero digits kept? Yes.
- Are padding zeroes added? No.
```hint Check the boundary
Check a number containing an internal zero.
```
Overview: Expand each positive array value into its decimal digits while preserving both number order and digit order.