Python/sorts/patience_sort.py

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from __future__ import annotations
from bisect import bisect_left
from functools import total_ordering
from heapq import merge
"""
A pure Python implementation of the patience sort algorithm
For more information: https://en.wikipedia.org/wiki/Patience_sorting
This algorithm is based on the card game patience
For doctests run following command:
python3 -m doctest -v patience_sort.py
For manual testing run:
python3 patience_sort.py
"""
@total_ordering
class Stack(list):
def __lt__(self, other):
return self[-1] < other[-1]
def __eq__(self, other):
return self[-1] == other[-1]
def patience_sort(collection: list) -> list:
2021-10-04 03:33:42 +00:00
"""A pure implementation of patience sort algorithm in Python
:param collection: some mutable ordered collection with heterogeneous
comparable items inside
:return: the same collection ordered by ascending
Examples:
>>> patience_sort([1, 9, 5, 21, 17, 6])
[1, 5, 6, 9, 17, 21]
>>> patience_sort([])
[]
>>> patience_sort([-3, -17, -48])
[-48, -17, -3]
"""
stacks: list[Stack] = []
# sort into stacks
for element in collection:
new_stacks = Stack([element])
i = bisect_left(stacks, new_stacks)
if i != len(stacks):
stacks[i].append(element)
else:
stacks.append(new_stacks)
# use a heap-based merge to merge stack efficiently
collection[:] = merge(*(reversed(stack) for stack in stacks))
return collection
if __name__ == "__main__":
user_input = input("Enter numbers separated by a comma:\n").strip()
unsorted = [int(item) for item in user_input.split(",")]
print(patience_sort(unsorted))