sol3.py

"""
Project Euler Problem 3: https://projecteuler.net/problem=3

Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143?

References:
 - https://en.wikipedia.org/wiki/Prime_number#Unique_factorization
"""


defsolution(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):
raiseTypeError("Parameter n must be int or castable to int.")
ifn<=0:
raiseValueError("Parameter n must be greater than or equal to one.")
i=2
ans=0
ifn==2:
return2
whilen>2:
whilen%i!=0:
i+=1
ans=i
whilen%i==0:
n=n//i
i+=1
returnint(ans)


if__name__=="__main__":
print(f"{solution() =}")