Python:实现factorial recursive阶乘递归算法(附完整源码)

def factorial(n: int) -> int:
    if not isinstance(n, int):
        raise ValueError("factorial() only accepts integral values")
    if n < 0:
        raise ValueError("factorial() not defined for negative values")
    return 1 if n == 0 or n == 1 else n * factorial(n - 1)


if __name__ == "__main__":
    import doctest

    doctest.testmod()

1
2
3
4
5
6
7
8
9
10
11
12
13