Python/sorts/merge_sort_fastest.py
Tommy.Liu 3c40fda6a3 More elegant coding for merge_sort_fastest (#804)
* More elegant coding for merge_sort_fastest

* More elegant coding for merge_sort
2019-05-14 18:17:25 +08:00

47 lines
1.2 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)
'''
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=',')