A linked list is a fundamental data structure used in computer science to store a collection of elements. Unlike an array, which is a contiguous block of memory, a linked list consists of nodes that are connected through pointers.
What is a Node?
A node is the basic building block of a linked list. It contains two components: the data and the pointer to the next node. The data can be any type, such as an integer, string, or even another complex data structure.
Example:
Let’s consider an example of a linked list representing a sequence of numbers: 5 -> 10 -> 15 -> 20. Each number will be stored in a node.
Creating a Node
In HTML, we can define the structure of a node using the <div> tag and assign classes to represent its components.
<div class="node">
<span class="data">5</span>
<span class="next"></span>
</div>The .node class represents the entire node, while the .data class represents the data component. The .next class represents the pointer to the next node.
Creating a Linked List
To create a linked list, we need to connect multiple nodes together. We do this by assigning the pointer of one node to another.
<div class="node first">
<span class="data">5</span>
<span class="next" id="pointer1"></span>
</div>
<div class="node">
<span class="data">10</span>
<span class="next" id="pointer2"></span>
</div>
<div class="node last">
<span class="data">15</span>
<span class="next"></span>
</div>In this example, the first node has a pointer (#pointer1) to the second node, and the second node has a pointer (#pointer2) to the third node. The last node doesn’t have a next pointer since it is the end of the linked list.
Traversing a Linked List
To access all the elements in a linked list, we need to traverse through each node. We start from the first node and follow the next pointers until we reach the end of the list.
- Step 1: Set a temporary variable current to point to the first node.
- Step 2: Repeat until current is null (end of the list):
- a) Access the data of current.
- b) Move current to its next node using its next pointer.
Using this algorithm, we can iterate through each element in a linked list and perform various operations like searching for an element or modifying its data.
The Advantages of Linked Lists
– Linked lists are dynamic data structures that can grow or shrink as needed.
– Insertion and deletion operations can be performed efficiently in a linked list.
– Linked lists don’t require contiguous memory allocation, unlike arrays.
The Disadvantages of Linked Lists
– Random access to elements is not possible in a linked list. To access an element, we need to start from the first node and traverse through the list.
– Extra memory is required to store the next pointers, increasing space complexity compared to arrays.
Linked lists are essential for implementing other data structures like stacks, queues, and trees. Understanding how linked lists work is fundamental in computer science and can greatly improve your problem-solving skills.
Now that you have a good understanding of what a linked list is and how it works, you can start implementing it in your own programs. Happy coding!