Return the k-th row of Pascal-like triangle

Problem

Given an integer rowIndex (0-indexed), return the rowIndex-th row of Pascal’s triangle.

Pascal’s triangle is defined as:

• Row 0 is [1]
• Each subsequent row starts and ends with 1
• Each interior element is the sum of the two elements directly above it:
  • row[i][j] = row[i-1][j-1] + row[i-1][j]

Input

• rowIndex : integer ( >= 0 )

Output

• An array/list of length rowIndex + 1 containing the values in that row.

Constraints (memory-focused)

• 0 <= rowIndex <= 10^5
• You should use O(rowIndex) extra space (a full 2D triangle may exceed memory limits).

Example

• rowIndex = 4 → [1, 4, 6, 4, 1]