Compute One Zero-Indexed Pascal Row
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Return the row at zero-based index `rowIndex` in Pascal's triangle. Row 0 is `[1]`. Every row begins and ends with 1; each interior entry adds the two entries directly above it.
```cpp
vector<int> getRow(int rowIndex);
```
### Examples
```text
Input: rowIndex = 4
Output: [1,4,6,4,1]
```
```text
Input: rowIndex = 2
Output: [1,2,1]
```
### Constraints
- `0 <= rowIndex <= 33`.
### Optional follow-up
Can you compute the row using only `O(rowIndex)` extra space?
Overview: Compute a zero-indexed Pascal row using descending in-place updates and only linear result storage.
