mirror of
https://github.com/TheAlgorithms/Python.git
synced 2024-11-24 05:21:09 +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
47 lines
1.3 KiB
Python
47 lines
1.3 KiB
Python
'''
|
|
Python implementation of the fastest merge sort algorithm.
|
|
Takes an average of 0.6 microseconds to sort a list of length 1000 items.
|
|
Best Case Scenario : O(n)
|
|
Worst Case Scenario : O(n^2) because native python functions:min, max and remove are already O(n)
|
|
'''
|
|
from __future__ import print_function
|
|
|
|
|
|
def merge_sort(collection):
|
|
"""Pure implementation of the fastest merge sort algorithm in Python
|
|
|
|
:param collection: some mutable ordered collection with heterogeneous
|
|
comparable items inside
|
|
:return: a 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]
|
|
"""
|
|
start, end = [], []
|
|
while len(collection) > 1:
|
|
min_one, max_one = min(collection), max(collection)
|
|
start.append(min_one)
|
|
end.append(max_one)
|
|
collection.remove(min_one)
|
|
collection.remove(max_one)
|
|
end.reverse()
|
|
return start + collection + end
|
|
|
|
|
|
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=',')
|