JAVA Program for Deletion from Nth Position of a Doubly Linked List

February 15, 2023

JAVA Program to Delete a Node from the Nth Position

In this page we’ll take a look at a comprehensive explanation of Deleting a Node from a specific index of a Doubly Linked List, one of the most widely used operation on a Doubly Linked List

Steps to be followed while Deleting a Node from the Nth Position of a Doubly Linked List

Check for the presence of Node in the List, if there exists some Nodes, Continue.
Now, to delete a node from Nth position of the Doubly Linked List, we’ll have to delete and redirect various links of the Linked List.
First of all the next pointer of the (n-1)th Node of the Linked List will now point to the address of the (n+1)th node of the Doubly Linked List.
Now the Previous Pointer of the (n+1)th Node of the Linked List will now be re-directed to the address of (n-1)th node of the List.

Example:

If we have a list (10 –> 20 –> 30 –> 40 –> 50) and we have to delete a node on the Second Index of the List, that is i=2, then after deleting a node. Updated Linked list will be (10 –> 20 –> 40 –> 50) . We will be learning more about the whole process in the explanation below.

Deletion in doubly linked list

Deletion from beginning in doubly linked list

Deletion from end in doubly linked list

Insertion and Deletion in doubly linked list

Insertion in the middle in a doubly linked list

Algorithm to be used for the Deletion of a Node from a Specific Index of a Doubly Linked List

IF(HEAD == NULL)
- RETURN
ELSE
- NODE CURRENT = HEAD;
- INT POS =N;
FOR(INT I = 1; I < POS; I++)
- CURRENT = CURRENT.NEXT
IF(CURRENT == HEAD)
- HEAD = CURRENT.NEXT
ELSE IF(CURRENT == TAIL)
- TAIL = TAIL.PREV
ELSE
- CURRENT.PREV.NEXT = CURRENT.NEXT
- CURRENT.NEXT.PREV = CURRENT.PREV
CURRENT = NULL

Java Program for Deletion from the Nth Position of a Doubly Linked List

Method 1

Method 2

Method 1

Run

import java.lang.*;

class DoublyLinkedList
{
    Node head;
    // not using parameterized constructor would by default
    // force head instance to become null
    // Node head = null;  // can also do this, but not required

    // Node Class
    class Node
    {
        int data;
        Node next, prev;

        Node (int x)		// parameterized constructor
        {
            data = x;
            next = null;
            prev = null;
        }
    }

    public void insertBeginning (int data)
    {
        // Creating newNode memory & assigning data value
        Node freshNode = new Node (data);

        freshNode.next = head;
        freshNode.prev = null;

        // if DLL had already >=1 nodes
        if (head != null)
            head.prev = freshNode;

        // changing head to this
        head = freshNode;
    }


    // function for deleting Nth node
    public void deletenth (int n)
    {
        if (head == null)
        {
            return;
        }
        else
        {
            Node current = head;
            int pos = n;
            for (int i = 1; i < pos; i++)
            {
                current = current.next;
            }
            if (current == head)
            {
                head = current.next;
            }
            else if (current == null)
            {
                current = current.prev;
            }
            else
            {
                current.prev.next = current.next;
                current.next.prev = current.prev;
            }
            //Delete the middle node
            current = null;
        }
    }


    void printList ()
    {
        //Node current will point to head
        Node curr = head;
        if (head == null)
        {
            System.out.println ("List is empty");
            return;
        }
        while (curr != null)
        {
            //Prints each node by increasing order of the pointer
            System.out.print (curr.data + " ");
            curr = curr.next;
        }
        System.out.println ();
    }

}

class Main
{

    public static void main (String args[])
    {
        DoublyLinkedList doublylist = new DoublyLinkedList ();

        doublylist.insertBeginning (3);
        doublylist.insertBeginning (2);
        doublylist.insertBeginning (1);
        doublylist.insertBeginning (4);
        doublylist.insertBeginning (7);

        System.out.println ("List before deletion : ");
        doublylist.printList ();


        doublylist.deletenth (2);
        doublylist.deletenth (3);
        System.out.println ("List after deleting 2nd node : ");
        doublylist.printList ();

    }
}

Output

List before deletion : 
7 4 1 2 3 
List after deleting 2nd node : 
7 1 3

Method 2

Run

import java.lang.*;

// Node Class
class Node {
    int data;
    Node next, prev;

    Node(int x) // parameterized constructor
    {
        data = x;
        next = null;
        prev = null;
    }
}

class Main
{
    static Node insertBeginning(Node head, int data)
    {
        // Creating newNode memory & assigning data value
        Node newNode = new Node(data);

        newNode.next = head;
        newNode.prev = null;

        // if DLL had already >=1 nodes
        if(head !=null)
            head.prev = newNode;

        // changing head to this
        head = newNode;

        return head;
    }

    // function for deleting Nth node
    static Node deletenth (int n, Node head)
    {
        if (head == null)
        {
            return head;
        }
        else
        {
            Node current = head;
            int pos = n;
            for (int i = 1; i < pos; i++)
            {
                current = current.next;
            }
            if (current == head)
            {
                head = current.next;
            }
            else if (current == null)
            {
                current = current.prev;
            }
            else
            {
                current.prev.next = current.next;
                current.next.prev = current.prev;
            }
            //Delete the middle node
            current = null;
        }
        return head;
    }


    static void printList (Node head)
    {
        //Node current will point to head
        Node curr = head;
        if (head == null)
        {
            System.out.println ("List is empty");
            return;
        }
        while (curr != null)
        {
            //Prints each node by increasing order of the pointer
            System.out.print (curr.data + " ");
            curr = curr.next;
        }
        System.out.println ();
    }


    // required for insertAfterPosition() method
    static int getLength(Node node){
        int size=0;

        // traverse to the last node each time incrementing the size
        while(node!=null)
        {
            node = node.next;
            size++;
        }
        return size;
    }

    public static void main(String args[])
    {
        Node head = null;
        head = insertBeginning(head,3);
        head = insertBeginning(head,2);
        head = insertBeginning(head,1);
        head = insertBeginning(head,4);
        head = insertBeginning(head,7);


        System.out.println ("List before deletion : ");
        printList (head);

        head=deletenth (2,head);
        head=deletenth (3,head);
        System.out.println ("List after deleting 2nd node : ");
        printList (head);
    }
}

Output

List before deletion : 
7 4 1 2 3 
List after deleting 2nd node : 
7 1 3

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Doubly Linked List

Introduction to Doubly Linked list in Data Structure
Doubly Linked List in – C | C++ | Java
Insertion in doubly linked list – C | C++ | Java
- Insertion at beginning in doubly linked list – C | C++ | Java
- Insertion at end in doubly linked list – C | C++ | Java
- Insertion at n^th node in doubly linked list – C | C++ | Java
Deletion in doubly linked list – C | C++ | Java
- Deletion from beginning in doubly linked list : C | C++ | Java
- Deletion from nth in doubly linked list : C | C++ | Java
- Deletion from end in doubly linked list : C | C++ | Java
Insertion and Deletion in doubly linked list – C | C++ | Java
Insertion in the middle in a doubly linked list – C | C++ | Java