mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 13:31:07 +00:00
02c0daf9e5
* Adding variable to fade out ambiguity * More readability on merge sorting algorithm * Updating merge_sort_fastest description and explaining why * Adding tests file with imports * Standardazing filenames and function names * Adding test cases and test functions * Adding test loop * Putting 'user oriented code' inside main condition for having valid imports * Fixing condition * Updating tests: adding cases and todo list * Refactoring first euler problem's first solution
56 lines
1.5 KiB
Python
56 lines
1.5 KiB
Python
"""
|
|
This is a pure python implementation of the merge sort algorithm
|
|
|
|
For doctests run following command:
|
|
python -m doctest -v merge_sort.py
|
|
or
|
|
python3 -m doctest -v merge_sort.py
|
|
|
|
For manual testing run:
|
|
python merge_sort.py
|
|
"""
|
|
from __future__ import print_function
|
|
|
|
|
|
def merge_sort(collection):
|
|
"""Pure implementation of the merge sort algorithm in Python
|
|
|
|
:param collection: some mutable ordered collection with heterogeneous
|
|
comparable items inside
|
|
:return: the same collection ordered by ascending
|
|
|
|
Examples:
|
|
>>> merge_sort([0, 5, 3, 2, 2])
|
|
[0, 2, 2, 3, 5]
|
|
|
|
>>> merge_sort([])
|
|
[]
|
|
|
|
>>> merge_sort([-2, -5, -45])
|
|
[-45, -5, -2]
|
|
"""
|
|
def merge(left, right):
|
|
'''merge left and right
|
|
:param left: left collection
|
|
:param right: right collection
|
|
:return: merge result
|
|
'''
|
|
result = []
|
|
while left and right:
|
|
result.append(left.pop(0) if left[0] <= right[0] else right.pop(0))
|
|
return result + left + right
|
|
if len(collection) <= 1:
|
|
return collection
|
|
mid = len(collection) // 2
|
|
return merge(merge_sort(collection[:mid]), merge_sort(collection[mid:]))
|
|
|
|
|
|
if __name__ == '__main__':
|
|
try:
|
|
raw_input # Python 2
|
|
except NameError:
|
|
raw_input = input # Python 3
|
|
|
|
user_input = raw_input('Enter numbers separated by a comma:\n').strip()
|
|
unsorted = [int(item) for item in user_input.split(',')]
|
|
print(*merge_sort(unsorted), sep=',') |