Function solution

project_euler/problem_003/sol1.py:51–101

Returns the largest prime factor of a given number n. >>> solution(13195) 29 >>> solution(10) 5 >>> solution(17) 17 >>> solution(3.4) 3 >>> solution(0) Traceback (most recent call last): ... ValueError: Parameter n must be greater than or equ

(n: int = 600851475143)

def solution(n: int = 600851475143) -> int:
    """
    Returns the largest prime factor of a given number n.

    >>> solution(13195)
    29
    >>> solution(10)
    5
    >>> solution(17)
    17
    >>> solution(3.4)
    3
    >>> solution(0)
    Traceback (most recent call last):
        ...
    ValueError: Parameter n must be greater than or equal to one.
    >>> solution(-17)
    Traceback (most recent call last):
        ...
    ValueError: Parameter n must be greater than or equal to one.
    >>> solution([])
    Traceback (most recent call last):
        ...
    TypeError: Parameter n must be int or castable to int.
    >>> solution("asd")
    Traceback (most recent call last):
        ...
    TypeError: Parameter n must be int or castable to int.
    """

    try:
        n = int(n)
    except TypeError, ValueError:
        raise TypeError("Parameter n must be int or castable to int.")
    if n <= 0:
        raise ValueError("Parameter n must be greater than or equal to one.")
    max_number = 0
    if is_prime(n):
        return n
    while n % 2 == 0:
        n //= 2
    if is_prime(n):
        return n
    for i in range(3, int(math.sqrt(n)) + 1, 2):
        if n % i == 0:
            if is_prime(n // i):
                max_number = n // i
                break
            elif is_prime(i):
                max_number = i
    return max_number


if __name__ == "__main__":