mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-10-07 06:09:28 +00:00
f438440ac5
* Added doctest and more explanation about Dijkstra execution. * tests were not passing with python2 due to missing __init__.py file at number_theory folder * Removed the dot at the beginning of the imported modules names because 'python3 -m doctest -v data_structures/hashing/*.py' and 'python3 -m doctest -v data_structures/stacks/*.py' were failing not finding hash_table.py and stack.py modules. * Moved global code to main scope and added doctest for project euler problems 1 to 14. * Added test case for negative input. * Changed N variable to do not use end of line scape because in case there is a space after it the script will break making it much more error prone. * Added problems description and doctests to the ones that were missing. Limited line length to 79 and executed python black over all scripts. * Changed the way files are loaded to support pytest call. * Added __init__.py to problems to make them modules and allow pytest execution. * Added project_euler folder to test units execution * Changed 'os.path.split(os.path.realpath(__file__))' to 'os.path.dirname()' * Added Burrows-Wheeler transform algorithm. * Added changes suggested by cclauss * Fixes for issue 'Fix the LGTM issues #1024'. * Added doctest for different parameter types and negative values. * Fixed doctest issue added at last commit.
85 lines
2.1 KiB
Python
85 lines
2.1 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.
|
|
"""
|
|
from __future__ import print_function, division
|
|
import math
|
|
|
|
try:
|
|
raw_input # Python 2
|
|
except NameError:
|
|
raw_input = input # Python 3
|
|
|
|
|
|
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(raw_input().strip())))
|