Deletion in Doubly Linked List

   Last Updated: 06 October, 2024       🕓  5 Mins

Hello, In this tutorial, we will see all about the delete operation in a doubly linked list. In the delete operation, we will delete an existing node from the doubly linked list from any position.

In a Doubly Linked List, we can delete a node at the following positions:

1. Delete node at the beginning

2. Delete node at the specific position

3. Delete node at the end

Create a node class

public class Node { public int data; // Data stored in the node public Node prev; // Reference to the next node in the list public Node next; // Reference to the previous node in the list // Constructor to initialize a new node with data public Node(int new_data) { data = new_data; prev = null; next = null; } }

1. Delete a node from the beginning of the doubly linked list

In the below given example we will see how to delete an existing node from the beginning or front the doubly linked list.

// Java Program to delete a node from the beginning of a Doubly Linked List public class DeleteAtBeginningInDLL { static Node head; // Method to insert a node in doubly linked list static void insertNode(int data) { Node newNode = new Node(data); Node last = head; if (head == null) { head = newNode; return; } while (last.next != null) { last = last.next; } last.next = newNode; newNode.prev = last; } // Method to delete the first node (head) of a doubly linked list static Node deleteHead() { // Before deleting a node just make sure list should not be empty if (head == null) { System.out.println("List is empty"); return null; } // Move head to the next node head = head.next; // If list contains only one node, head will be null // Otherwise, set previous node as null in the new head if (head != null) { head.prev = null; } return head; } // Method to print the doubly linked list static void printList() { Node curr = head; while (curr != null) { System.out.print(curr.data + " "); curr = curr.next; } System.out.println(); // Line break } public static void main(String[] args) { // Create a doubly linked list insertNode(10); insertNode(20); insertNode(30); insertNode(40); insertNode(50); System.out.println("Original doubly linked list:"); printList(); deleteHead(); System.out.println("\nAfter Deletion Head, Doubly Linked List data: "); printList(); } }

Output

  Original doubly linked list:
  10 20 30 40 50 

  After Deletion Head, Doubly Linked List data: 
  20 30 40 50  

2. Delete a node at the specific position of the doubly linked list

In the below given example we will see how to delete an existing node from the any position of the doubly linked list.

// Java Program to delete node at a specific position in Doubly Linked List public class DeleteAtSpecPositionInDLL { static Node head; // Method to insert a node in doubly linked list static void insertNode(int data) { Node newNode = new Node(data); Node last = head; if (head == null) { head = newNode; return; } while (last.next != null) { last = last.next; } last.next = newNode; newNode.prev = last; } // Method to delete a node at a specific position static Node delPos(Node head, int position) { // Before deleting a node just make sure list should not be empty if (head == null) { System.out.println("List is empty"); return head; } Node curr = head; // Traverse to the node at the given position for (int i = 1; curr != null && i < position; ++i) { curr = curr.next; } // If the position is out of range if (curr == null) return head; // Update the previous node's next pointer if (curr.prev != null) curr.prev.next = curr.next; // Update the next node's prev pointer if (curr.next != null) curr.next.prev = curr.prev; // If the node to be deleted is the head node if (head == curr) head = curr.next; // Deallocate memory for the deleted node curr = null; return head; } // Method to print the doubly linked list static void printList(Node head) { Node curr = head; while (curr != null) { System.out.print(curr.data + " "); curr = curr.next; } System.out.println(); } public static void main(String[] args) { // Create a doubly linked list insertNode(10); insertNode(20); insertNode(30); insertNode(40); insertNode(50); System.out.println("Original doubly linked list:"); printList(head); // Deleting node at 2nd Position head = delPos(head, 2); printList(head); } }

Output

  Original doubly linked list:
  10 20 30 40 50 
  10 30 40 50 

3. Delete a node from the end of the doubly linked list

In the below given example we will see how to delete an existing node from the end or last the doubly linked list.

// Java Program to delete a node from the end/last of the Doubly Linked List public class DeleteAtEndInDLL { static Node head; // Method to insert a node in doubly linked list static void insertNode(int data) { Node newNode = new Node(data); Node last = head; if (head == null) { head = newNode; return; } while (last.next != null) { last = last.next; } last.next = newNode; newNode.prev = last; } // Method to delete the last node of the doubly linked list static Node deleteLastNode() { // Before deleting a node just make sure list should not be empty if (head == null) { System.out.println("List is empty"); return null; } // Delete is not possible, if list has only one node if (head.next == null) { return null; } // Traverse to the last node Node curr = head; while (curr.next != null) { curr = curr.next; } // Update the previous node's next pointer if (curr.prev != null) { curr.prev.next = null; } // Return the updated head return head; } static void printList() { Node curr = head; while (curr != null) { System.out.print(curr.data + " "); curr = curr.next; } System.out.println(); } public static void main(String[] args) { // Create a doubly linked list insertNode(10); insertNode(20); insertNode(30); insertNode(40); insertNode(50); System.out.println("Original doubly linked list:"); printList(); deleteLastNode(); System.out.println("\nAfter Deletion End, Doubly Linked List data: "); printList(); } }

Output

  Original doubly linked list:
  10 20 30 40 50 

  After Deletion End, Doubly Linked List data: 
  10 20 30 40