帕斯卡三角输出

def generate_pascals_triangle(num_rows):
    triangle = []
    for row_num in range(num_rows):
        # The first and last row elements are always 1.
        row = [None for _ in range(row_num + 1)]
        row[0], row[-1] = 1, 1
        # Each triangle element is equal to the sum of the elements
        # above-and-to-the-left and above-and-to-the-right.
        for j in range(1, len(row) - 1):
            row[j] = triangle[row_num - 1][j - 1] + triangle[row_num - 1][j]
        triangle.append(row)
    return triangle

# 生成前5行的帕斯卡三角
num_rows = 5
pascals_triangle = generate_pascals_triangle(num_rows)
for row in pascals_triangle:
    print(row)

def generate_pascals_triangle(num_rows):
    triangle = []
    for row_num in range(num_rows):
        row = [1] * (row_num + 1)
        for j in range(1, len(row) - 1):
            row[j] = triangle[row_num - 1][j - 1] + triangle[row_num - 1][j]
        triangle.append(row)
    return triangle

def generate_pascals_triangle(num_rows):
    if num_rows == 0:
        return []
    triangle = [[1]]
    for row_num in range(1, num_rows):
        row = [1]
        last_row = triangle[-1]
        for j in range(1, row_num):
            row.append(last_row[j - 1] + last_row[j])
        row.append(1)
        triangle.append(row)
    return triangle