Python/sorts/quick_sort.py

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"""
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
"""
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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]
"""
length = len(collection)
if length <= 1:
return collection
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else:
# Use the last element as the first pivot
pivot = collection.pop()
# Put elements greater than pivot in greater list
# Put elements lesser than pivot in lesser list
greater, lesser = [], []
for element in collection:
if element > pivot:
greater.append(element)
else:
lesser.append(element)
return quick_sort(lesser) + [pivot] + quick_sort(greater)
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if __name__ == "__main__":
user_input = input("Enter numbers separated by a comma:\n").strip()
unsorted = [int(item) for item in user_input.split(",")]
print(quick_sort(unsorted))