mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-12-18 09:10:16 +00:00
79 lines
1.9 KiB
Python
79 lines
1.9 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.
|
|
"""
|
|
import math
|
|
|
|
|
|
def isprime(no):
|
|
if no == 2:
|
|
return True
|
|
elif no % 2 == 0:
|
|
return False
|
|
sq = int(math.sqrt(no)) + 1
|
|
for i in range(3, sq, 2):
|
|
if no % i == 0:
|
|
return False
|
|
return True
|
|
|
|
|
|
def solution(n):
|
|
"""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) as e:
|
|
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.")
|
|
maxNumber = 0
|
|
if isprime(n):
|
|
return n
|
|
else:
|
|
while n % 2 == 0:
|
|
n = n / 2
|
|
if isprime(n):
|
|
return int(n)
|
|
else:
|
|
n1 = int(math.sqrt(n)) + 1
|
|
for i in range(3, n1, 2):
|
|
if n % i == 0:
|
|
if isprime(n / i):
|
|
maxNumber = n / i
|
|
break
|
|
elif isprime(i):
|
|
maxNumber = i
|
|
return maxNumber
|
|
|
|
|
|
if __name__ == "__main__":
|
|
print(solution(int(input().strip())))
|