LinkedList in Data Structures

Sakshi Dhameja 10 min read

19 May 2023

Beginner

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LinkedList

Introduction

Welcome to the world of data structures! Are you interested in learning how to manage, implement and manipulate your own data? In this article, we will put a spotlight on LinkedList one of the preferred methods for organizing your data. A linked list is like a chain that consists of multiple components or nodes, each connected together using references. It is an incredibly effective way to store and organize information so much so that parts or all of it are found across many programming languages and frameworks. So if you're looking for an efficient method for structuring your data, look no further than a linked list! Keep reading as we delve into what makes LinkedLists so powerful and discover why they might be just what you need.

What is linked list in data structure?

Linked list in data structure is a fundamental concept in a data structure that is widely used and revered by developers and computer scientists alike. In simpler terms, a linked list is a data structure that consists of a sequence of nodes, each containing a reference to the next node in the sequence. This allows for efficient insertions and deletions, as well as dynamic allocation of memory. What makes linked lists so useful is their flexibility, making them a popular choice for a wide range of applications including database management systems and mobile app development. The beauty of linked lists lies in their simplicity and elegance, making them a great example of the power of abstract thinking and creative problem-solving in computer science.

Application of linked list

Linked lists are commonly used in computer programming for their ability to efficiently store and manipulate collections of data. Here are some common application of linked lists:
Implementing data structures: Linked lists are commonly used to implement data structures like stacks, queues, and hash tables.
Memory allocation: Linked lists are also used in memory allocation, where a linked list of free memory blocks is maintained, and new memory is allocated by removing blocks from the free list.
File systems: Linked lists are used in file systems to represent directories and files.
Music and video players: Linked lists are used in music and video players to maintain playlists.
Graphs: Linked lists are used to represent graphs where each node in the list represents a vertex and its adjacent vertices are stored in a linked list.
Games: Linked lists are used to represent game boards where each element in the list represents a cell on the board.

Linked List Implementations in Python, Java, and C++ Examples

 
 class Node:
 
    # Creating a node
 
    def __init__(self, item):
 
        self.item = item
 
        self.next = None
 
class LinkedList:
 
    def __init__(self):
 
        self.head = None
 
if __name__ == '__main__':
 
    linked_list = LinkedList()
 
    # Assign item values
 
    linked_list.head = Node(1)
 
    second = Node(2)
 
    third = Node(3)
 
    # Connect nodes
 
    linked_list.head.next = second
 
    second.next = third
 
    # Print the linked list item
 
    while linked_list.head != None:
 
        print(linked_list.head.item, end=" ")
         linked_list.head = linked_list.head.next

 
 // Linked list implementation in Java
 
class LinkedList {
 
  // Creating a node
 
  Node head;
 
  static class Node {
 
    int value;
 
    Node next;
 
    Node(int d) {
 
      value = d;
 
      next = null;
 
    }
 
  }
 
  public static void main(String[] args) {
 
    LinkedList linkedList = new LinkedList();
 
    // Assign value values
 
    linkedList.head = new Node(1);
 
    Node second = new Node(2);
 
    Node third = new Node(3);
 
    // Connect nodess
 
    linkedList.head.next = second;
 
    second.next = third;
 
    // printing node-value
 
    while (linkedList.head != null) {
 
      System.out.print(linkedList.head.value + " ");
 
      linkedList.head = linkedList.head.next;
 
    }
 
  }
 }

 
 // Linked list implementation in C++
 
#include <bits/stdc++.h>
 
#include <iostream>
 
using namespace std;
 
// Creating a node
 
class Node {
 
   public:
 
  int value;
 
  Node* next;
 
};
 
int main() {
 
  Node* head;
 
  Node* one = NULL;
 
  Node* two = NULL;
 
  Node* three = NULL;
 
  // allocate 3 nodes in the heap
 
  one = new Node();
 
  two = new Node();
 
  three = new Node();
 
  // Assign value values
 
  one->value = 1;
 
  two->value = 2;
 
  three->value = 3;
 
  // Connect nodes
 
  one->next = two;
 
  two->next = three;
 
  three->next = NULL;
 
  // print the linked list value
 
  head = one;
 
  while (head != NULL) {
 
    cout << head->value;
 
    head = head->next;
 
  }
 }

Types of linked list in data structure

Singly-linked list: In a singly linked list, each node contains a reference to the next node in the list. This means that each node can only be traversed in one direction, from the head to the tail.
Doubly linked list: In a doubly linked list, each node contains references to both the next and previous nodes in the list. This allows for traversal in both directions, making it easier to insert or delete nodes at any point in the list.
Circular linked list: In a circular linked list, the last node in the list contains a reference to the first node, creating a loop. This means that traversal can continue indefinitely, as long as there are nodes in the list.
Sorted linked list: In a sorted linked list, the nodes are arranged in a specific order, such as alphabetical or numerical order. This allows for faster searching and sorting of data but can make inserting or deleting nodes more complicated.
Unsorted linked list: In an unsorted linked list, the nodes are not arranged in any particular order. This can make searching and sorting slower, but makes inserting or deleting nodes easier.

Advantages of linked list

Dynamic size: Linked lists can be dynamically resized during runtime, which means that anyone can add or remove elements from the list without worrying about the size limitations of the underlying data structure.
Efficient insertion and deletion: Adding or removing elements from a linked list is very efficient because the user only needs to update the links between nodes, rather than moving elements around in memory like would with an array.
Flexibility: Linked lists can be used to implement a variety of data structures, such as stacks, queues, and hash tables. This flexibility makes linked lists a versatile tool for many programming tasks.
Memory efficiency: Linked lists can be more memory efficient than arrays because they only require as much memory as necessary to store the data and pointers to the next node.
Easy implementation: Implementing a linked list is relatively easy, as the developer only need to define a node structure and a few functions to manipulate the links between nodes.

Disadvantages of linked list

Dynamic Memory Allocation: Linked lists require dynamic memory allocation, which can be slower than static memory allocation used by arrays. Allocating and deallocating memory for each node can also cause memory fragmentation, leading to memory wastage.
Traversal: Unlike arrays, linked lists do not allow direct access to individual nodes. Traversing a linked list requires iterating through all the nodes from the beginning of the list until the desired node is found. This can be inefficient and slow, especially for large linked lists.
Extra Space: Linked lists require extra space for storing the pointers to the next node. This can increase the memory usage compared to arrays, especially for small data types.
No Random Access: Linked lists do not support random access, i.e., accessing a specific node directly without traversing the list. This can be a significant disadvantage for some applications that require fast access to individual elements.
Cache Misses: Linked lists can suffer from cache misses, i.e., when the CPU needs to access data that is not in the cache. This can slow down the execution of programs that frequently access data from linked lists.
Limited Usage: Linked lists are not suitable for all types of applications. For example, they are not efficient for sorting or searching large amounts of data, which can be better handled by other data structures such as trees or hash tables.

Summary

In conclusion, a linked list in data structure is a powerful tool for different applications. Linked lists can offer efficient solutions for storing and manipulating data in comparison to other data structures. They are versatile and widely applicable across many programming languages. As a developer, familiarizing yourself with linked lists can open new opportunities when it comes to building projects from scratch or optimizing existing ones. Take the time to research more on linked list concepts and use them as part of your development arsenal. Learning this data structure may just be the key to unlocking your next idea! So why not get started today? Try experimenting with linked list algorithms and see what creativity they can inspire!