"""Math utilities."""


def factorial(n: int) -> int:
    """Return n! for a non-negative integer n.

    Raises TypeError if n is not an int (bool is rejected), ValueError if n < 0.
    """
    if isinstance(n, bool) or not isinstance(n, int):
        raise TypeError(f"n must be an int, got {type(n).__name__}")
    if n < 0:
        raise ValueError(f"n must be >= 0, got {n}")
    result = 1
    for i in range(2, n + 1):
        result *= i
    return result