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Quiz SimulationLINKED LIST
LINKED LIST
What is Linked List?
In simple words, a linked list is a way to organize a list of items, like a chain of
connected blocks. Each block (or node) contains both the item you want to store and a
reference or link to the next block in the chain. It's a bit like a train where each car
(node) is connected to the one in front of it, allowing you to go from one car to the
next in a sequence.
This structure makes it easy to add or remove items in the middle of the list because
you can simply change the links between the blocks. However, it's not as efficient for
random access (jumping to a specific item) as some other data structures like arrays.
Linked lists are commonly used in programming to create dynamic lists that can grow or
shrink as needed.
Basic Operations on Linked List
Some of the basic operations for Queue in Data Structure are:
● Enqueue() – Adds (or stores) an element to the end of the queue..
● Dequeue() – Removal of elements from the queue.
● Peek() or front()- Acquires the data element available at the front
node of the queue without deleting it.
● rear() – This operation returns the element at the rear end without
removing it.
● isFull() – Validates if the queue is full.
● isNull() – Checks if the queue is empty.
Types of Linked List
There are different types of queues:
● Input Restricted Queue: This is a simple queue. In this type of
queue, the input can be taken from only one end but deletion can be
done from any of the ends.
● Output Restricted Queue: This is also a simple queue. In this type
of queue, the input can be taken from both ends but deletion can be
done from only one end.
● Circular Queue: This is a special type of queue where the last
position is connected back to the first position. Here also the
operations are performed in FIFO order.
● Double-Ended Queue (Dequeue): In a double-ended queue the
insertion and deletion operations, both can be performed from both
ends. To know more refer this.
● Priority Queue: A priority queue is a special queue where the
elements are accessed based on the priority assigned to them.
Implentation Of Linked List
Linked lists have various applications in computer science and software development due
to their flexibility and efficient dynamic memory allocation. Here are some common
applications of linked lists:
Dynamic Memory Allocation:
Linked lists are often used in programming languages and
systems to manage memory efficiently. They allow for dynamic allocation and deallocation
of memory blocks, which is crucial for tasks like managing heaps and creating data
structures like stacks and queues.
Data Structures:
Linked lists serve as the foundation for building more complex data
structures.
For example:
*Stacks: A linked list can be used to implement a stack data structure, where elements
are pushed and popped from one end (the head).
*Queues: Linked lists can be used to implement a queue, with elements enqueued at the
tail and dequeued from the head.
*Hash Tables: Separate chaining, a technique used in hash table implementations, employs
linked lists to handle collisions.
● File Systems:
Some file systems, such as Unix's "ext2," use linked lists to
maintain the
structure of files and directories. Each entry in a directory is a node in the linked
list.
● Music and Video Playlists:
Media players often use linked lists to manage
playlists,
where each song or video is a node in the list, and you can move between them
sequentially.
● LRU (Least Recently Used) Cache:
LRU caches use a linked list to maintain the
order of
recently used items. The least recently used item is evicted when the cache is full.
Advantages of Linked List
● Linked lists offer several advantages in various programming and data structure
scenarios. Here are some of the key advantages of using linked lists:
● Efficient Insertions and Deletions:
Linked lists excel at inserting and deleting
elements at arbitrary positions within the list. These operations typically have a time
complexity of O(1) if you have a reference to the node where you want to perform the
operation.
● Memory Efficiency:
Linked lists can be more memory-efficient than arrays or
dynamic
arrays (like Python lists or C++ vectors) because they allocate memory for each element
separately and don't require a contiguous block of memory.
● No Overflows:
Unlike arrays, linked lists don't suffer from overflow issues
because you
can keep adding elements as long as you have available memory.
● Support for Complex Structures:
Linked lists can be used to build more complex
data
structures, such as doubly linked lists (with links to both the next and previous nodes)
and circular linked lists.
● Constant-Time Insertions/Deletions at Head:
Adding or removing elements at the
beginning
of a singly linked list is a constant-time (O(1)) operation since you only need to
update the reference to the new head node.
● Ease of Merge:
When working with multiple linked lists, merging them together is
typically more efficient than merging arrays or dynamic arrays.
Disadvantages of Linked List
Linked lists have several disadvantages and limitations, which should be considered when
choosing them as a data structure for a particular application. Here are some of the key
disadvantages of linked lists:
● No Random Access:
Unlike arrays or dynamic arrays, linked lists do not provide
constant-time random access to elements. Accessing an element at a specific position
typically requires traversing the list from the beginning or from a known reference
point, resulting in O(n) time complexity for access.
● Memory Overhead:
Each node in a linked list contains not only the data but also a
reference (or link) to the next node, which can lead to increased memory overhead
compared to an array where only the data is stored.
● Inefficient for Reverse Traversal:
Singly linked lists are not efficient for reverse
traversal (traversing the list from end to beginning) because they don't have references
to the previous nodes. Doubly linked lists can address this limitation but at the cost
of increased memory overhead.
● Insertion and Deletion in Middle:
While linked lists excel at inserting and deleting
elements at the beginning or end, inserting or deleting elements in the middle of the
list can be less efficient. You need to traverse the list to find the insertion or
deletion point, resulting in O(n) time complexity.
● Difficulty in Maintaining Consistency:
Manipulating linked lists, especially in
multithreaded environments, can be complex and require additional synchronization
mechanisms to maintain consistency and avoid data corruption.