""" 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 """ def circle_sort(collection: list) -> list: """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] >>> 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: list, low: int, high: int) -> bool: """ >>> arr = [5,4,3,2,1] >>> circle_sort_util(lst, 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[left] > collection[right]: collection[left], collection[right] = ( collection[right], collection[left], ) swapped = True left += 1 right -= 1 if left == right and collection[left] > collection[right + 1]: 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))