Untitled

# Double Linked List

class Node:
    def __init__(self,data =None,plink =None,nlink =None):
        self.data = data
        self.plink = plink
        self.nlink = nlink


class DoubleLinkedList:
    def __init__(self):
        self.head = None

    def insert_end(self,ndata):
        iNode = Node(ndata)

        if self.head == None:
            self.head = iNode
            return
        
        curNode = self.head

        while curNode.nlink is not None:
            curNode = curNode.nlink

        curNode.nlink = iNode
        iNode.plink = curNode

    def insert_begin(self,ndata):
        iNode = Node(ndata)

        if self.head is None:
            self.head = iNode
            return
        
        iNode.nlink = self.head
        self.head.plink = iNode
        self.head = iNode

    def inser_in_nth(self,ndata,n):
        if n == 0:
            self.insert_begin(ndata)
            return
        
        iNode = Node(ndata)

        curNode = self.head
        c = 0

        while curNode is not None and c < n-1:
            curNode = curNode.nlink
            c += 1

        if curNode is None:
            return
        
        iNode.nlink = curNode.nlink  # Link new node to the next node
        if curNode.nlink is not None:  # If not inserting at the end
            curNode.nlink.plink = iNode  # Update the previous link of the next node
        curNode.nlink = iNode  # Link current node to the new node
        iNode.plink = curNode  # Link new node back to the current node
        # CurNode ndata curNode.nlink

    def delete_head(self):
        if self.head is None:
            print("No List")
            return
    
        if self.head.nlink is None:
            self.head = None
            return
        
        self.head = self.head.nlink
        self.head.plink = None

    def delete_end(self):
        if self.head is None:
            print("No List")
            return
    
        if self.head.nlink is None:
            self.head = None
            return
        
        curNode = self.head
        while curNode.nlink is not None:
            curNode = curNode.nlink
        
        curNode.plink.nlink = None
        curNode.plink = None #Breaks backward link

    def display(self):
        if self.head is None:
            print("List is empty")
            return

        curNode = self.head
        while curNode is not None:
            print(curNode.data, end=" -> ")
            curNode = curNode.nlink
        
        print("None")  # End of list

    def display_reverse(self, curNode):
        if curNode is None:
            print("None", end=" <- ")  # Print None at the start
            return
        
        self.display_reverse(curNode.nlink)  # Recursive call to the next node
        print(curNode.data, end=" <- ")