input: Write a function to generate the last row of Pascal's Triangle.
  assert pascal_triangle(1) == [1]
  assert pascal_triangle(4) == [1, 4, 6, 4, 1]
  assert pascal_triangle(5) == [1, 5, 10, 10, 5, 1]
output: def pascal_triangle(n):
      if n == 0:
          return [1]
      row = [1]
      for _ in range(n):
          row = [x + y for x, y in zip([0] + row, row + [0])]
      return row