Python - 杨辉三角

版权声明：欢迎转载并请注明出处，谢谢~~ https://blog.csdn.net/chimomo/article/details/46639231

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
YangHuiTriangle.py - by Chimomo
"""


# Triangle generator.
def generate_triangle():
    li = [1]
    while True:
        yield li
        li = [1] + [li[i] + li[i + 1] for i in range(0, len(li) - 1)] + [1]


# Get m_triangles within rank = (rank).
def get_triangles(rank):
    triangles = [[1]]
    i = 0
    for tri in generate_triangle():
        i += 1
        # Continue the loop since m_triangles is already initialized with [[1]].
        if i == 1:
            continue
        triangles.append(tri)
        if i == rank:
            return triangles


# Print m_triangles with well format.
def print_triangles(triangles, width):
    column_width = len(triangles[:]) * width
    for triangle in triangles:
        triangle_line = []
        for triangle_content in triangle:
            triangle_line.append('{0:^{1}}'.format(str(triangle_content), width))
        print('{0:^{1}}'.format(''.join(triangle_line), column_width))


m_triangles = get_triangles(6)
print_triangles(m_triangles, len(m_triangles[:-1][len(m_triangles[:-1]) // 2]) + 3)

print('开始测试')
# 期待输出:
# [1]
# [1, 1]
# [1, 2, 1]
# [1, 3, 3, 1]
# [1, 4, 6, 4, 1]
# [1, 5, 10, 10, 5, 1]
# [1, 6, 15, 20, 15, 6, 1]
# [1, 7, 21, 35, 35, 21, 7, 1]
# [1, 8, 28, 56, 70, 56, 28, 8, 1]
# [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
layer = 0
results = []
for t in generate_triangle():
    print(t)
    results.append(t)
    layer = layer + 1
    if layer == 10:
        break
if results == [
    [1],
    [1, 1],
    [1, 2, 1],
    [1, 3, 3, 1],
    [1, 4, 6, 4, 1],
    [1, 5, 10, 10, 5, 1],
    [1, 6, 15, 20, 15, 6, 1],
    [1, 7, 21, 35, 35, 21, 7, 1],
    [1, 8, 28, 56, 70, 56, 28, 8, 1],
    [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
]:
    print('测试通过!')
else:
    print('测试失败!')