



from __future__ import annotations

from collections.abc import Iterator
from typing import Any



class     lowerCAmelCase_		:
       def __init__(      self,      SCREAMING_SNAKE_CASE_	)					->		int:
          UpperCamelCase   :  Any						     =     data
          UpperCamelCase   :  Node | None						     =     None






class     lowerCAmelCase_		:
       def __init__(      self	)					->		int:
          UpperCamelCase   :  List[Any]						     =     None
          UpperCamelCase   :  Optional[Any]						     =     None
       def __iter__(      self	)					->		Iterator[Any]:
          UpperCamelCase   :  int						     =     self.head
          while self.head:
             yield node.data
             UpperCamelCase   :  List[str]						     =     node.next
             if node == self.head:
                break
       def __len__(      self	)					->		int:
          return sum(1 for _ in self	)
       def __repr__(      self	)					->		Tuple:
          return "->".join(str(SCREAMING_SNAKE_CASE_	) for item in iter(self	)	)
       def  snake_case_	(      self,      SCREAMING_SNAKE_CASE_	)					->		None:
          self.insert_nth(len(self	),      SCREAMING_SNAKE_CASE_	)
       def  snake_case_	(      self,      SCREAMING_SNAKE_CASE_	)					->		None:
          self.insert_nth(0,      SCREAMING_SNAKE_CASE_	)
       def  snake_case_	(      self,      SCREAMING_SNAKE_CASE_,      SCREAMING_SNAKE_CASE_	)					->		None:
          if index < 0 or index > len(self	):
             raise IndexError('list index out of range.'	)
          UpperCamelCase   :  Any						     =     Node(SCREAMING_SNAKE_CASE_	)
          if self.head is None:
             UpperCamelCase   :  Tuple						     =     new_node  # first node points itself
             UpperCamelCase   :  Union[str, Any]						     =     new_node
          elif index == 0:  # insert at head
             UpperCamelCase   :  str						     =     self.head
             UpperCamelCase   :  int						     =     new_node
          else:
             UpperCamelCase   :  Optional[int]						     =     self.head
             for _ in range(index - 1	):
                UpperCamelCase   :  Optional[Any]						     =     temp.next
             UpperCamelCase   :  Optional[int]						     =     temp.next
             UpperCamelCase   :  Optional[Any]						     =     new_node
             if index == len(self	) - 1:  # insert at tail
                UpperCamelCase   :  List[str]						     =     new_node
       def  snake_case_	(      self	)					->		Optional[Any]:
          return self.delete_nth(0	)
       def  snake_case_	(      self	)					->		Any:
          return self.delete_nth(len(self	) - 1	)
       def  snake_case_	(      self,      SCREAMING_SNAKE_CASE_ = 0	)					->		Any:
          if not 0 <= index < len(self	):
             raise IndexError('list index out of range.'	)
          UpperCamelCase   :  Optional[int]						     =     self.head
          if self.head == self.tail:  # just one node
             UpperCamelCase   :  int						     =     None
          elif index == 0:  # delete head node
             UpperCamelCase   :  Optional[Any]						     =     self.tail.next.next
             UpperCamelCase   :  Dict						     =     self.head.next
          else:
             UpperCamelCase   :  str						     =     self.head
             for _ in range(index - 1	):
                UpperCamelCase   :  Dict						     =     temp.next
             UpperCamelCase   :  Any						     =     temp.next
             UpperCamelCase   :  Dict						     =     temp.next.next
             if index == len(self	) - 1:  # delete at tail
                UpperCamelCase   :  Dict						     =     temp
          return delete_node.data






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






def 		UpperCamelCase     (       )     ->					None:
   UpperCamelCase   :  Optional[int]						     =     CircularLinkedList()
   assert len(snake_case__     ) == 0
   assert circular_linked_list.is_empty() is True
   assert str(snake_case__     ) == ""

   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(snake_case__     ) == i
      circular_linked_list.insert_nth(snake_case__	,					i + 1     )
   assert str(snake_case__     ) == "->".join(str(snake_case__     ) for i in range(1	,					6     )     )

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

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

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

   assert circular_linked_list.is_empty() is False


if __name__ == "__main__":
    import doctest

    doctest.testmod()








from abc import ABC, abstractmethod
from argparse import ArgumentParser



class     lowerCAmelCase_		(  a__							):
       @staticmethod
       @abstractmethod
       def  snake_case_	(      SCREAMING_SNAKE_CASE_	)					->		int:
          raise NotImplementedError()






       @abstractmethod
       def  snake_case_	(      self	)					->		str:
          raise NotImplementedError()



