计算1！- 2！+3！-……+n!麻烦用Python解答一下叭！感谢！
# -*- coding: utf-8 -*-
def fac(n):
if n == 1:
return 1
return n * fac(n - 1)
def fun(n):
sum = 0
for i in range(1, n + 1):
if i % 2 == 0:
sum -= fac(i)
else:
sum += fac(i)
return sum
if __name__ == '__main__':
print(fun(3))