
"""simple docstring"""

from __future__ import annotations

from collections.abc import Iterator
from typing import Any
class      _UpperCAmelCase							:




      def __init__(							self   ,       lowercase_							)						->					Optional[int]:
          UpperCAmelCase									=					data
          UpperCAmelCase									=					None

class      _UpperCAmelCase							:




      def __init__(							self							)						->					List[Any]:
          UpperCAmelCase									=					None
          UpperCAmelCase									=					None




      def __iter__(							self							)						->					Iterator[Any]:
          UpperCAmelCase									=					self.head
          while self.head:
              yield node.data
              UpperCAmelCase									=					node.next
              if node == self.head:
                  break




      def __len__(							self							)						->					int:
          return sum(1 for _ in self							)




      def __repr__(							self							)						->					int:
          return "->".join(str(lowercase_							) for item in iter(self							)							)




      def     a_      (							self   ,       lowercase_							)						->					None:
          self.insert_nth(len(self							)   ,       lowercase_							)




      def     a_      (							self   ,       lowercase_							)						->					None:
          self.insert_nth(0   ,       lowercase_							)




      def     a_      (							self   ,       lowercase_   ,       lowercase_							)						->					None:
          if index < 0 or index > len(self							):
              raise IndexError('list index out of range.'							)
          UpperCAmelCase									=					Node(lowercase_							)
          if self.head is None:
              UpperCAmelCase									=					new_node  # first node points itself
              UpperCAmelCase									=					UpperCAmelCase									=					new_node
          elif index == 0:  # insert at head
              UpperCAmelCase									=					self.head
              UpperCAmelCase									=					UpperCAmelCase									=					new_node
          else:
              UpperCAmelCase									=					self.head
              for _ in range(index - 1							):
                  UpperCAmelCase									=					temp.next
              UpperCAmelCase									=					temp.next
              UpperCAmelCase									=					new_node
              if index == len(self							) - 1:  # insert at tail
                  UpperCAmelCase									=					new_node




      def     a_      (							self							)						->					Optional[int]:
          return self.delete_nth(0							)




      def     a_      (							self							)						->					Any:
          return self.delete_nth(len(self							) - 1							)




      def     a_      (							self   ,       lowercase_ = 0							)						->					Any:
          if not 0 <= index < len(self							):
              raise IndexError('list index out of range.'							)
          UpperCAmelCase									=					self.head
          if self.head == self.tail:  # just one node
              UpperCAmelCase									=					UpperCAmelCase									=					None
          elif index == 0:  # delete head node
              UpperCAmelCase									=					self.tail.next.next
              UpperCAmelCase									=					self.head.next
          else:
              UpperCAmelCase									=					self.head
              for _ in range(index - 1							):
                  UpperCAmelCase									=					temp.next
              UpperCAmelCase									=					temp.next
              UpperCAmelCase									=					temp.next.next
              if index == len(self							) - 1:  # delete at tail
                  UpperCAmelCase									=					temp
          return delete_node.data




      def     a_      (							self							)						->					bool:
          return len(self							) == 0




def     lowercase__						(					) ->      None:






    """simple docstring"""




    UpperCAmelCase									=					CircularLinkedList()
    assert len(lowerCAmelCase ) == 0
    assert circular_linked_list.is_empty() is True
    assert str(lowerCAmelCase ) == ""

    try:
        circular_linked_list.delete_front()
        raise AssertionError  # This should not happen
    except IndexError:
        assert True  # This should happen

    try:
        circular_linked_list.delete_tail()
        raise AssertionError  # This should not happen
    except IndexError:
        assert True  # This should happen

    try:
        circular_linked_list.delete_nth(-1 )
        raise AssertionError
    except IndexError:
        assert True

    try:
        circular_linked_list.delete_nth(0 )
        raise AssertionError
    except IndexError:
        assert True

    assert circular_linked_list.is_empty() is True
    for i in range(5 ):
        assert len(lowerCAmelCase ) == i
        circular_linked_list.insert_nth(lowerCAmelCase ,				i + 1 )
    assert str(lowerCAmelCase ) == "->".join(str(lowerCAmelCase ) for i in range(1 ,				6 ) )

    circular_linked_list.insert_tail(6 )
    assert str(lowerCAmelCase ) == "->".join(str(lowerCAmelCase ) for i in range(1 ,				7 ) )
    circular_linked_list.insert_head(0 )
    assert str(lowerCAmelCase ) == "->".join(str(lowerCAmelCase ) for i in range(0 ,				7 ) )

    assert circular_linked_list.delete_front() == 0
    assert circular_linked_list.delete_tail() == 6
    assert str(lowerCAmelCase ) == "->".join(str(lowerCAmelCase ) for i in range(1 ,				6 ) )
    assert circular_linked_list.delete_nth(2 ) == 3

    circular_linked_list.insert_nth(2 ,				3 )
    assert str(lowerCAmelCase ) == "->".join(str(lowerCAmelCase ) for i in range(1 ,				6 ) )

    assert circular_linked_list.is_empty() is False


if __name__ == "__main__":
   import doctest

   doctest.testmod()





"""simple docstring"""

from abc import ABC, abstractmethod
from argparse import ArgumentParser
class      _UpperCAmelCase							(		SCREAMING_SNAKE_CASE_							):




      @staticmethod
      @abstractmethod
      def     a_      (							lowercase_							)						->					Optional[Any]:
          raise NotImplementedError()




      @abstractmethod
      def     a_      (							self							)						->					Any:
          raise NotImplementedError()



