""" This is a pure python implementation of the pancake sort algorithm For doctests run following command: python3 -m doctest -v pancake_sort.py or python -m doctest -v pancake_sort.py For manual testing run: python pancake_sort.py """ def pancake_sort(arr): """Sort Array with Pancake Sort. :param arr: Collection containing comparable items :return: Collection ordered in ascending order of items Examples: >>> pancake_sort([0, 5, 3, 2, 2]) [0, 2, 2, 3, 5] >>> pancake_sort([]) [] >>> pancake_sort([-2, -5, -45]) [-45, -5, -2] """ cur = len(arr) while cur > 1: # Find the maximum number in arr mi = arr.index(max(arr[0:cur])) # Reverse from 0 to mi arr = arr[mi::-1] + arr[mi + 1 : len(arr)] # Reverse whole list arr = arr[cur - 1 :: -1] + arr[cur : len(arr)] cur -= 1 return arr if __name__ == "__main__": user_input = input("Enter numbers separated by a comma:\n").strip() unsorted = [int(item) for item in user_input.split(",")] print(pancake_sort(unsorted))