Python/sorts/quick_sort.py

68 lines
1.6 KiB
Python

"""
This is a pure python implementation of the quick sort algorithm
For doctests run following command:
python -m doctest -v quick_sort.py
or
python3 -m doctest -v quick_sort.py
For manual testing run:
python quick_sort.py
"""
from __future__ import print_function
from random import shuffle
def sort(collection):
shuffle(collection)
return quick_sort(collection)
def quick_sort(collection):
"""Pure implementation of quick sort algorithm in Python
:param collection: some mutable ordered collection with heterogeneous
comparable items inside
:return: the same collection ordered by ascending
Examples:
>>> quick_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> quick_sort([])
[]
>>> quick_sort([-2, -5, -45])
[-45, -5, -2]
"""
less = []
equal = []
greater = []
if len(collection) > 1:
pivot = collection[0]
for x in collection:
if x < pivot:
less.append(x)
if x == pivot:
equal.append(x)
if x > pivot:
greater.append(x)
return quick_sort(less) + equal + quick_sort(greater)
else:
return collection
if __name__ == '__main__':
import sys
# For python 2.x and 3.x compatibility: 3.x has not raw_input builtin
# otherwise 2.x's input builtin function is too "smart"
if sys.version_info.major < 3:
input_function = raw_input
else:
input_function = input
user_input = input_function('Enter numbers separated by a comma:\n')
unsorted = [int(item) for item in user_input.split(',')]
print(sort(unsorted))