



from typing import Any




class 							lowerCAmelCase__  :







     def __init__(       self      :     str			,		_A      :     Any):
           A__	:							Union[str, Any]						    = data
           A__	:							Optional[Any]						    = None







     def __repr__(       self      :     int):
           return F'Node({self.data})'




class 							lowerCAmelCase__  :







     def __init__(       self      :     int):
           A__	:							Any						    = None







     def __iter__(       self      :     List[str]):
           A__	:							List[str]						    = self.head
           while node:
                 yield node.data
                 A__	:							Optional[int]						    = node.next







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







     def __repr__(       self      :     Optional[int]):
           return "->".join([str(__A) for item in self])







     def __getitem__(       self      :     int			,		_A      :     int):
           if not 0 <= index < len(self):
                 raise ValueError("list index out of range.")
           for i, node in enumerate(self):
                 if i == index:
                       return node
           return None







     def __setitem__(       self      :     Tuple			,		_A      :     int			,		_A      :     Any):
           if not 0 <= index < len(self):
                 raise ValueError("list index out of range.")
           A__	:							Union[str, Any]						    = self.head
           for _ in range(__A):
                 A__	:							Tuple						    = current.next
           A__	:							str						    = data







     def  _lowercase			(       self      :     int			,		_A      :     Any):
           self.insert_nth(len(self)			,		__A)







     def  _lowercase			(       self      :     List[str]			,		_A      :     Any):
           self.insert_nth(0			,		__A)







     def  _lowercase			(       self      :     str			,		_A      :     int			,		_A      :     Any):
           if not 0 <= index <= len(self):
                 raise IndexError("list index out of range")
           A__	:							int						    = Node(__A)
           if self.head is None:
                 A__	:							List[Any]						    = new_node
           elif index == 0:
                 A__	:							Any						    = self.head  # link new_node to head
                 A__	:							Union[str, Any]						    = new_node
           else:
                 A__	:							List[Any]						    = self.head
                 for _ in range(index - 1):
                       A__	:							Tuple						    = temp.next
                 A__	:							List[str]						    = temp.next
                 A__	:							List[str]						    = new_node







     def  _lowercase			(       self      :     Union[str, Any]):  # print every node data
           print(self)







     def  _lowercase			(       self      :     Dict):
           return self.delete_nth(0)







     def  _lowercase			(       self      :     Tuple):  # delete from tail
           return self.delete_nth(len(self) - 1)







     def  _lowercase			(       self      :     Optional[Any]			,		_A      :     int = 0):
           if not 0 <= index <= len(self) - 1:  # test if index is valid
                 raise IndexError("List index out of range.")
           A__	:							Union[str, Any]						    = self.head  # default first node
           if index == 0:
                 A__	:							List[Any]						    = self.head.next
           else:
                 A__	:							List[str]						    = self.head
                 for _ in range(index - 1):
                       A__	:							Any						    = temp.next
                 A__	:							Any						    = temp.next
                 A__	:							List[Any]						    = temp.next.next
           return delete_node.data







     def  _lowercase			(       self      :     Any):
           return self.head is None







     def  _lowercase			(       self      :     Any):
           A__	:							List[Any]						    = None
           A__	:							Optional[int]						    = self.head

           while current:
                 # Store the current node's next node.
                 A__	:							int						    = current.next
                 # Make the current node's next point backwards
                 A__	:							Tuple						    = prev
                 # Make the previous node be the current node
                 A__	:							str						    = current
                 # Make the current node the next node (to progress iteration)
                 A__	:							List[str]						    = next_node
           # Return prev in order to put the head at the end
           A__	:							Optional[Any]						    = prev




def 	snake_case__       (					)		->		Union[str, Any]:







      """simple docstring"""

      A__	:							Optional[int]						    = LinkedList()
      assert linked_list.is_empty() is True
      assert str(_lowercase       ) == ""

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

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

      for i in range(1_0       ):
            assert len(_lowercase       ) == i
            linked_list.insert_nth(_lowercase							,     i + 1       )
      assert str(_lowercase       ) == "->".join(str(_lowercase       ) for i in range(1							,     1_1       )       )

      linked_list.insert_head(0       )
      linked_list.insert_tail(1_1       )
      assert str(_lowercase       ) == "->".join(str(_lowercase       ) for i in range(0							,     1_2       )       )

      assert linked_list.delete_head() == 0
      assert linked_list.delete_nth(9       ) == 1_0
      assert linked_list.delete_tail() == 1_1
      assert len(_lowercase       ) == 9
      assert str(_lowercase       ) == "->".join(str(_lowercase       ) for i in range(1							,     1_0       )       )

      assert all(linked_list[i] == i + 1 for i in range(0							,     9       )       ) is True

      for i in range(0							,     9       ):
            A__	:							List[str]						    = -i
      assert all(linked_list[i] == -i for i in range(0							,     9       )       ) is True

      linked_list.reverse()
      assert str(_lowercase       ) == "->".join(str(_lowercase       ) for i in range(-8							,     1       )       )
def 	snake_case__       (					)		->		List[str]:







      """simple docstring"""

      A__	:							Optional[int]						    = [
          -9,
          1_0_0,
          Node(7_7_3_4_5_1_1_2       ),
          "dlrow olleH",
          7,
          5_5_5_5,
          0,
          -1_9_2.5_5_5_5_5,
          "Hello, world!",
          77.9,
          Node(1_0       ),
          None,
          None,
          12.20,
      ]
      A__	:							Dict						    = LinkedList()

      for i in test_input:
            linked_list.insert_tail(_lowercase       )

      # Check if it's empty or not
      assert linked_list.is_empty() is False
      assert (
          str(_lowercase       ) == "-9->100->Node(77345112)->dlrow olleH->7->5555->0->"
          "-192.55555->Hello, world!->77.9->Node(10)->None->None->12.2"
      )

      # Delete the head
      A__	:							int						    = linked_list.delete_head()
      assert result == -9
      assert (
          str(_lowercase       ) == "100->Node(77345112)->dlrow olleH->7->5555->0->-192.55555->"
          "Hello, world!->77.9->Node(10)->None->None->12.2"
      )

      # Delete the tail
      A__	:							Optional[Any]						    = linked_list.delete_tail()
      assert result == 12.2
      assert (
          str(_lowercase       ) == "100->Node(77345112)->dlrow olleH->7->5555->0->-192.55555->"
          "Hello, world!->77.9->Node(10)->None->None"
      )

      # Delete a node in specific location in linked list
      A__	:							int						    = linked_list.delete_nth(1_0       )
      assert result is None
      assert (
          str(_lowercase       ) == "100->Node(77345112)->dlrow olleH->7->5555->0->-192.55555->"
          "Hello, world!->77.9->Node(10)->None"
      )

      # Add a Node instance to its head
      linked_list.insert_head(Node("Hello again, world!"       )       )
      assert (
          str(_lowercase       )
          == "Node(Hello again, world!)->100->Node(77345112)->dlrow olleH->"
          "7->5555->0->-192.55555->Hello, world!->77.9->Node(10)->None"
      )

      # Add None to its tail
      linked_list.insert_tail(_lowercase       )
      assert (
          str(_lowercase       )
          == "Node(Hello again, world!)->100->Node(77345112)->dlrow olleH->"
          "7->5555->0->-192.55555->Hello, world!->77.9->Node(10)->None->None"
      )

      # Reverse the linked list
      linked_list.reverse()
      assert (
          str(_lowercase       )
          == "None->None->Node(10)->77.9->Hello, world!->-192.55555->0->5555->"
          "7->dlrow olleH->Node(77345112)->100->Node(Hello again, world!)"
      )
def 	snake_case__       (					)		->		Tuple:







      """simple docstring"""

      from doctest import testmod

      testmod()

      A__	:							int						    = LinkedList()
      linked_list.insert_head(input("Inserting 1st at head "       ).strip()       )
      linked_list.insert_head(input("Inserting 2nd at head "       ).strip()       )
      print("\nPrint list:"       )
      linked_list.print_list()
      linked_list.insert_tail(input("\nInserting 1st at tail "       ).strip()       )
      linked_list.insert_tail(input("Inserting 2nd at tail "       ).strip()       )
      print("\nPrint list:"       )
      linked_list.print_list()
      print("\nDelete head"       )
      linked_list.delete_head()
      print("Delete tail"       )
      linked_list.delete_tail()
      print("\nPrint list:"       )
      linked_list.print_list()
      print("\nReverse linked list"       )
      linked_list.reverse()
      print("\nPrint list:"       )
      linked_list.print_list()
      print("\nString representation of linked list:"       )
      print(_lowercase       )
      print("\nReading/changing Node data using indexing:"       )
      print(F'Element at Position 1: {linked_list[1]}'       )
      A__	:							Union[str, Any]						    = input("Enter New Value: "       ).strip()
      print("New list:"       )
      print(_lowercase       )
      print(F'length of linked_list is : {len(_lowercase       )}'       )


if __name__ == "__main__":
  main()




snake_case    :						Tuple  =						'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
def 	snake_case__       (					)		->		None:







						"""simple docstring"""

						A__	:							Union[str, Any]						    = input("Enter message: "       )
						A__	:							Tuple						    = input("Enter key [alphanumeric]: "       )
						A__	:							Optional[Any]						    = input("Encrypt/Decrypt [e/d]: "       )

						if mode.lower().startswith("e"       ):
												A__	:							Tuple						    = "encrypt"
												A__	:							str						    = encrypt_message(__lowercase							,     __lowercase       )
						elif mode.lower().startswith("d"       ):
												A__	:							Optional[Any]						    = "decrypt"
												A__	:							Union[str, Any]						    = decrypt_message(__lowercase							,     __lowercase       )

						print(F'\n{mode.title()}ed message:'       )
						print(__lowercase       )
def 	snake_case__       (					__lowercase							,     __lowercase       )		->		str:







						"""simple docstring"""

						return translate_message(__lowercase							,     __lowercase							,     "encrypt"       )
def 	snake_case__       (					__lowercase							,     __lowercase       )		->		str:







						"""simple docstring"""

						return translate_message(__lowercase							,     __lowercase							,     "decrypt"       )
def 	snake_case__       (					__lowercase							,     __lowercase							,     __lowercase       )		->		str:







						"""simple docstring"""

						A__	:							Dict						    = []
						A__	:							Union[str, Any]						    = 0
						A__	:							List[Any]						    = key.upper()

						for symbol in message:
												A__	:							List[str]						    = LETTERS.find(symbol.upper()       )
												if num != -1:
																		if mode == "encrypt":
																								num += LETTERS.find(key[key_index]       )
																		elif mode == "decrypt":
																								num -= LETTERS.find(key[key_index]       )

																		num %= len(__lowercase       )

																		if symbol.isupper():
																								translated.append(LETTERS[num]       )
																		elif symbol.islower():
																								translated.append(LETTERS[num].lower()       )

																		key_index += 1
																		if key_index == len(__lowercase       ):
																								A__	:							Optional[int]						    = 0
												else:
																		translated.append(__lowercase       )
						return "".join(__lowercase       )


if __name__ == "__main__":
		main()