Have you ever clicked:

Back

Forward

inside a browser?

That feature works efficiently because the system can move in both directions.

A Doubly Linked List provides exactly that capability.

Unlike a Singly Linked List, every node knows:

who comes next

who came before

1. What is a Doubly Linked List?

A Doubly Linked List is a collection of nodes where each node stores:

data

next pointer

previous pointer

Visual representation:

null ← [10] ⇄ [20] ⇄ [30] → null

This allows traversal in both directions.

2. Node Structure

public class DNode {

int data; DNode prev; DNode next;

DNode(int data) { this.data = data; this.prev = null; this.next = null; }

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}

What's New?

Compared to a Singly Linked List:

Node next;

becomes

DNode prev;

DNode next;

One extra pointer unlocks bidirectional navigation.

3.…