新手求教：请问怎样用python 显示杨辉三角，任意输入一个数N，输出一个N+1层的杨辉三角。

发布网友发布时间：2022-10-16 08:09

共1个回答

热心网友时间：2023-10-17 10:00

我来试一下：

#!/usr/bin/python
# coding:utf-8
n = -1
while n < 0:
   n = raw_input("Enter a nonnegative integer >= 0:")
   try:
       n = int(n)
   except:
       print "please enter integer!"
       n = -1
tmppascal = [0,]* (2 * n + 3)
pascal = []
for i in range(n + 2):
   pascal += [tmppascal[:],]
center = n + 1
pascal[1][center] = 1
x = y = 0
for i in range(2, n + 2):
   if n % 2 == 1:
       if i % 2 == 0:
           x = 1
           y = 2 * n + 2
       else:
           x = 2
           y = 2 * n + 1
   else:
       if i % 2 == 1:
           x = 1
           y = 2 * n + 2
       else:
           x = 2
           y = 2 * n + 1
   for j in range(x, y, 2):
       pascal[i][j] = pascal[i - 1][j - 1] + pascal[i - 1][j + 1]
if n % 2 == 0:
   max = pascal[n + 1][center]
else:
   max = pascal[n + 1][center - 1]
maxlen = len(str(max))
for row in pascal[1:]:
   for col in row[1:-1]:
       if col == 0:
           col = ""
       fm = '{0: ^' + str(maxlen) + '}'
       print fm.format(col),
   print