"""
This is a Python implementation of the circle sort algorithm
For doctests run following command:
python3 -m doctest -v circle_sort.py
For manual testing run:
python3 circle_sort.py
"""
from collections.abc import MutableSequence
from typing import Any, Protocol
class Comparable(Protocol):
def __lt__(self, other: Any, /) -> bool: ...
def circle_sort[T: Comparable](
collection: MutableSequence[T],
) -> MutableSequence[T]:
"""A pure Python implementation of circle sort algorithm
:param collection: a mutable collection of comparable items in any order
:return: the same collection in ascending order
Examples:
>>> circle_sort([0, 5, 3, 2, 2])
[0, 2, 2, 3, 5]
>>> circle_sort([])
[]
>>> circle_sort([-2, 5, 0, -45])
[-45, -2, 0, 5]
>>> circle_sort(["d", "a", "c", "b"])
['a', 'b', 'c', 'd']
>>> circle_sort([2.5, -1.0, 0.0])
[-1.0, 0.0, 2.5]
>>> circle_sort([1, "a"])
Traceback (most recent call last):
...
TypeError: '<' not supported between instances of 'str' and 'int'
>>> collections = ([], [0, 5, 3, 2, 2], [-2, 5, 0, -45])
>>> all(sorted(collection) == circle_sort(collection) for collection in collections)
True
"""
if len(collection) < 2:
return collection
def circle_sort_util(collection: MutableSequence[T], low: int, high: int) -> bool:
"""
>>> arr = [5,4,3,2,1]
>>> circle_sort_util(arr, 0, 2)
True
>>> arr
[3, 4, 5, 2, 1]
"""
swapped = False
if low == high:
return swapped
left = low
right = high
while left < right:
if collection[right] < collection[left]:
collection[left], collection[right] = (
collection[right],
collection[left],
)
swapped = True
left += 1
right -= 1
if left == right and collection[right + 1] < collection[left]:
collection[left], collection[right + 1] = (
collection[right + 1],
collection[left],
)
swapped = True
mid = low + int((high - low) / 2)
left_swap = circle_sort_util(collection, low, mid)
right_swap = circle_sort_util(collection, mid + 1, high)
return swapped or left_swap or right_swap
is_not_sorted = True
while is_not_sorted is True:
is_not_sorted = circle_sort_util(collection, 0, len(collection) - 1)
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(circle_sort(unsorted))