Python/project_euler/problem_03/sol2.py
Edward Nuno 54401387a8
Hacktoberfest 2020: Add style improvements for Project Euler Problem 03 (#2917)
* Fix typehints in project_euler/problem01

Squashed commit of the following:

commit 6801d073b31bf702814861cd3b07b634ca295bfa
Author: Archaengel <god11341258@gmail.com>
Date:   Mon Oct 5 16:40:10 2020 -0700

    Fix typehints in project_euler/problem01

commit 29afc3af114abd1b99dc3f7c8fc99128229db131
Author: Archaengel <god11341258@gmail.com>
Date:   Mon Oct 5 15:06:34 2020 -0700

    Add typehints and default argument for project_euler/problem_01

* Add default args, typehints, and expand variable names for PE prob 02

* Add style improvements for first solution of PE Problem 02

* Add default arg and typehints for second solution of PE Problem 02

* Add default arg for third solution of PE Problem 02

* Add style improvements for 1st soln of PE problem 03

* Add default arg and typehints for 2nd soln of PE problem 03

* Add default arg for 3rd soln of PE problem 03

* Remove unnecessary newlines

* Remove unnecessary newlines

* Fix end of file for 2nd soln in PE problem 03
2020-10-06 20:24:39 +05:30

57 lines
1.4 KiB
Python

"""
Problem:
The prime factors of 13195 are 5,7,13 and 29. What is the largest prime factor
of a given number N?
e.g. for 10, largest prime factor = 5. For 17, largest prime factor = 17.
"""
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 or equal to one.
>>> solution(-17)
Traceback (most recent call last):
...
ValueError: Parameter n must be greater or equal to one.
>>> solution([])
Traceback (most recent call last):
...
TypeError: Parameter n must be int or passive of cast to int.
>>> solution("asd")
Traceback (most recent call last):
...
TypeError: Parameter n must be int or passive of cast to int.
"""
try:
n = int(n)
except (TypeError, ValueError):
raise TypeError("Parameter n must be int or passive of cast to int.")
if n <= 0:
raise ValueError("Parameter n must be greater or equal to one.")
prime = 1
i = 2
while i * i <= n:
while n % i == 0:
prime = i
n //= i
i += 1
if n > 1:
prime = n
return int(prime)
if __name__ == "__main__":
print(solution(int(input().strip())))