Linked lists are data structures that are commonly used in computer science. They are a dynamic data structure that stores elements in sequential order. Unlike arrays, linked lists do not require a contiguous block of memory. This article will explore linked list applications in computer science and the real world.
What is a Linked List?
A linked list is a linear data structure in which elements or nodes are linked together by pointers or references. Each node contains two parts: data and a pointer to the next node in the list. The first node is called the head, and the last node is called the tail. The head points to the first node, and the tail points to null or the end of the list.
Unlike arrays, linked lists do not require a contiguous block of memory to store elements. Instead, each element can be stored in any location in memory, and the pointer points to the next element in the list.
Applications of Linked List
This section aims to look at several applications of linked lists. The applications of linked lists are not limited to computer science, they can also be found in the real world.
Applications of Linked List in Computer Science
Here are some application of linked lists in computer science.
- Representing polynomials: Linked lists can be used to store and manipulate polynomials. Each node in the list represents a term in the polynomial, with the data part storing the coefficient and the exponent of the term.
- Polynomial manipulation: Using a linked list, we can perform various operations on polynomials, such as adding, subtracting, multiplying, and dividing them.
- Arithmetic operations on long integers: Linked lists can also be used to perform arithmetic operations on long integers. The digits of the integer can be stored in each node of the list, with the head representing the least significant digit.
- Implementing stacks and queues: Linked lists are commonly used to implement stacks and queues. Each node in the list represents an element in the stack or queue, with the head and tail pointers pointing to the top or bottom of the stack or queue, respectively.
- Implementing graphs: One of the important applications of Linked lists is implementing graphs, with the adjacent vertices stored in the nodes of the linked list. This representation is known as the adjacency list representation and is commonly used in graph algorithms such as breadth-first search and depth-first search.
Applications of Linked List in Real World
Here are some application of linked lists in the real world.
- Music players: Linked lists are commonly used in music players to create playlists and play songs either from the beginning or the end of the list. Each song in the playlist is stored as a node in the linked list, with the next pointer pointing to the next song in the list.
- Image viewers: Image viewers also use linked lists to enable users to easily navigate between images. Each image is stored as a node in the linked list, with the next pointer pointing to the next image in the list.
- Web browsers: Web browsers use linked lists to store the browsing history of the user, allowing them to easily navigate between previously visited pages using the forward and backward buttons. Each URL visited is stored as a node in the linked list, with the next pointer pointing to the next URL visited.
Applications of Singly Linked List
Here are some applications of a singly linked list, including:
- Implementing stacks and queues: Singly linked lists can be used to implement stacks and queues. In a stack, elements are added and removed from one end of the list, while in a queue, elements are added at one end and removed from the other end of the list.
- Navigation in web browsers: Singly linked lists can be used to store the browsing history in web browsers. Each URL visited is stored as a node in the list, with the next pointer pointing to the next URL visited.
- Implementing symbol tables: Symbol tables are data structures used to store key-value pairs. Singly-linked lists can be used to implement symbol tables, with each node storing a key-value pair.
- Hash table chaining: Hash table chaining is a technique used to handle collisions in hash tables. It involves using a singly linked list to store all the keys that hash to the same index in the table.
Applications of Doubly Linked List
Here are some applications of doubly linked list, including:
- Implementing music players: Doubly linked lists are commonly used in music players to enable users to easily navigate between songs. Each song in the playlist is stored as a node in the list, with the previous and next pointers pointing to the previous and next songs in the list.
- Implementing text editors: Doubly linked lists can be used to implement text editors, allowing users to easily insert, delete, and navigate through the text. Each line of text is stored as a node in the list, with the previous and next pointers pointing to the previous and next lines in the document.
- Implementing cache memory: Doubly linked lists can be used to implement cache memory, a small amount of high-speed memory used to temporarily store frequently accessed data. Each block of data stored in the cache is stored as a node in the list, with the previous and next pointers pointing to the previous and next blocks in the cache.
Applications of Circular Linked Lists
Circular linked lists also have good usage. A circular linked list is a linked list in which the last node points to the head instead of pointing to NULL.
- We can use Circular Linked List to implement advanced data structures like Fibonacci Heap.
- Circular lists are helpful in applications when you want to go around the list several times.
- When many programs are running on a PC, it is typical for the operating system to place them all on a list and then cycle over them, giving each one a chunk of time to execute before having them wait while the CPU is given to another.
- It is more convenient for the operating system to utilize a circular list so that it may cycle back to the beginning when it reaches the end of the list.
- Circular Linked List can be used to implement a queue. We do not need to maintain the head and rear pointer if we use a circular linked list. We can store a pointer to the last node of the list, and the head can always be obtained as the next of the list.
Advantages of linked list over arrays:
In this blog section, we will see some advantages of linked list over arrays.
- Dynamic Data Structure: Linked List being a dynamic data structure, can shrink and grow at the runtime by deallocating or allocating memory, so there is no need for an initial size in the linked list. Whereas in an array, an initial size has to be declared, and the number of elements cannot exceed that size.
- No Memory Wastage: As the size of a linked list can grow or shrink at runtime, there is no memory wastage. Only the required memory is allocated. In arrays, we have to first initialize it with a size that we may or may not fully use; hence wastage of memory may occur.
- Implementation: Some very helpful data structures like queues and stacks can easily be implemented using a Linked List.
- Insertion and Deletion Operation: In a Linked List, insertion and deletion operations are quite easy, as there is no need to shift every element after insertion or deletion.
- Only the address present in the pointers needs to be updated.
- While, in an array, we have to shift elements. Suppose an array is sorted, and we have to insert an element in it in a sorted way. Let arr= [ 1, 3 , 5, 7, ….. ] and we have to insert 2. So, all the elements after 1 have to move by one place towards the right.
Read More: Advantage and Disadvantage of Linked List Over Array
In conclusion, we explored linked list applications in computer science and the real world, covering their use in representing polynomials, implementing data structures, and enabling navigation in various applications. We also highlighted the applications of singly linked lists, doubly linked lists, and circular linked lists. Overall, a linked list is a valuable data structure with numerous applications in diverse fields.
Here are some frequently asked questions related to the application of linked lists.
Q1: Can a linked list be used to implement a binary tree?
Answer: Yes, a linked list can be used to implement a binary tree, where each node has two pointers, one for the left subtree and one for the right subtree.
Q2: How can linked lists be used in game development?
Answer: Linked lists can be used to implement a game’s animation system, where each frame is represented by a node in the linked list, and the animation is played by traversing the list.
Q3: How are linked lists used in operating systems?
Answer: Linked lists are used in operating systems to manage processes and threads, as well as to maintain data structures such as file system directories and open file lists.
Q4: Can linked lists be used for data compression?
Answer: Yes, linked lists can be used in data compression algorithms such as Huffman coding, where the frequency of each character is stored in a linked list and used to generate a binary code for that character.
Q5: Can linked lists be used for natural language processing?
Answer: Yes, linked lists can be used in natural language processing algorithms to represent and manipulate text data, such as generating word clouds or analyzing sentiment.
Q6: Can linked lists be used for image processing?
Answer: Yes, linked lists can be used in image processing algorithms to represent and manipulate pixel data, such as performing edge detection or image segmentation.