""" 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))