Doubly_linkedlist.py

# class Node:
#     def __init__(self, data):
#         self.data = data
#         self.prev = None
#         self.next = None


# class DoublyLinkedList:
#     def __init__(self):
#         self.head = None

#     def print_list(self):
#         if self.head is None:
#             return
#         temp = self.head
#         while temp.next is not None:
#             print(temp.data, end=" ")
#             temp = temp.next
#         print(temp.data)

#     def count_nodes(self):
#         count = 0
#         if self.head is None:
#             return 0
#         else:
#             temp = self.head
#             while temp.next is not None:
#                 count += 1
#                 temp = temp.next
#             return count + 1

#     def push_begin(self, data):
#         if self.head is None:
#             new_node = Node(data)
#             self.head = new_node
#         else:
#             new_node = Node(data)
#             new_node.next = self.head
#             self.head.prev = new_node
#             self.head = new_node

#     def push_end(self, data):
        
#         if self.head is None:
#             new_node = Node(data)
#             self.head = new_node
#         else:
#             new_node = Node(data)
#             temp = self.head
#             while temp.next is not None:
#                 temp = temp.next
#             temp.next = new_node
#             new_node.prev = temp

#     def push_middle(self, middle_node, data):
#         if middle_node is None:
#             print("There is no such middle node")
#             return
#         new_node = Node(data)
#         new_node.next = middle_node.next
#         new_node.prev = middle_node
#         if middle_node.next is not None:
#             middle_node.next.prev = new_node
#         middle_node.next = new_node

#     def delete_begin(self):
#         if self.head is None:
#             print("There is no linked list")
#             return
#         if self.head.next is None:
#             self.head = None
#             return
#         self.head = self.head.next
#         self.head.prev = None

#     def delete_end(self):
#         if self.head is None:
#             print("Linked list is empty")
#             return
#         if self.head.next is None:
#             self.head = None
#             return
#         temp = self.head
#         while temp.next is not None:
#             temp = temp.next
#         temp.prev.next = None

#     def add_node(self, pos, data):
#         position = pos
#         count = 0
#         new_node = Node(data)
#         temp = self.head
#         while count < position - 1:
#             temp = temp.next
#             count += 1
#         new_node.next = temp.next
#         new_node.prev = temp
#         if temp.next is not None:
#             temp.next.prev = new_node
#         temp.next = new_node

#     def reverse_linked_list(self):
#         temp = None
#         current = self.head
#         while current is not None:
#             temp = current.prev
#             current.prev = current.next
#             current.next = temp
#             current = current.prev
#         if temp is not None:
#             self.head = temp.prev

#     def remove_duplicates(self):
#         current = self.head
#         while current is not None and current.next is not None:
#             if current.data == current.next.data:
#                 current.next = current.next.next
#                 if current.next is not None:
#                     current.next.prev = current
#             else:
#                 current = current.next


# list1 = DoublyLinkedList()
# node1 = Node(10)
# node2 = Node(20)
# node3 = Node(30)
# node4 = Node(40)
# node5 = Node(40)
# node6 = Node(60)
# node7 = Node(60)

# list1.head = node1
# node1.next = node2
# node2.prev = node1
# node2.next = node3
# node3.prev = node2
# node3.next = node4
# node4.prev = node3
# node4.next = node5
# node5.prev = node4
# node5.next = node6
# node6.prev = node5
# node6.next = node7
# node7.prev = node6


# DoublyLinkedList.print_list(list1)
# DoublyLinkedList.remove_duplicates(list1)
# DoublyLinkedList.print_list(list1)









# -------------------------------------------------------------------------------------------------------------------------------

class Node:
    def __init__(self,data):
        self.data= data
        self.next = None
        self.prev = None

class LinkedList:
    def __init__(self):
        self.head  = None
        self.tail = None
    

    def push_begin(self,data):
        new_node = Node(data)
        if self.head == None:
            self.head = new_node
            self.tail = new_node
        else:
            new_node.next = self.head
            self.head.prev = new_node
            self.head = new_node




    def push_end(self, data):
        new_node = Node(data)
        if self.head == None:
            self.head = new_node
            self.tail = new_node
        else:
            self.tail.next = new_node
            new_node.prev = self.tail
            self.tail = new_node
            new_node.next = None


    def push_position(self, data, pos):
        new_node = Node(data)
        if self.head == None:
           print("list is empty")
        else:

            temp = self.head
            count = 0
            while(count<pos):
                count+=1
                tem = temp.next
            new_node.next = temp.next
            new_node.prev = temp
            # temp.next.prev = new_node
            # temp.next = new_node
            new_node.next.prev = new_node
            temp.next = new_node


    def delete_node(self,element):

        if self.head == None:
            return None
        else:
            temp = self.head
            while temp!=None and  temp.next!=None:
                if temp.next.data == element:
                    temp.next = temp.next.next
                    temp.next.next.prev = temp
                temp = temp.next
        

    def length_list(self):
        temp = self.head
        length =0
        while temp!=None:
            length+=1
            temp = temp.next
        return length
    

    def reverse_list(self):
        temp =  self.tail
        while temp!=None:
            print(temp.data, end=" ")
            temp = temp.prev
        print()


    def remove_duplicates(self):
        temp_list = []
        temp = self.head
        while temp!=None:
            if temp.data not in temp_list:
                print(temp.data, end=" ")
                temp_list.append(temp.data)
                temp = temp.next
        print()
            
            
    def print_list(self):
        temp = self.head
        while temp!=None:
            print(temp.data, end=" ")
            temp = temp.next
        print()



list1 = LinkedList()
list1.push_end(1)
list1.push_end(2)
list1.push_end(3)
list1.push_end(4)
list1.push_end(5)
list1.push_end(4)
list1.push_end(3)
list1.push_end(3)
list1.push_end(2)



list1.print_list()
# list1.delete_node(6)
# list1.print_list()



print(list1.length_list())
# list1.reverse_list()
list1.remove_duplicates()
# list1.print_list()