Mastering a programming language involves understanding the concept of a linked list as it forms the basis of a lot of algorithms in computer science. The data structure shows up in coding interviews, system designs, and real life applications quite a lot.
This blog aims to cover the definition and types of lists, comparisons with arrays, and applications in both tech and non-tech fields.
If you are a novice or preparing for interviews, this guide will step you through with Linked Lists to ensure mastery of the topic.
What Do You Mean By A Linked List?
A linked list is a form of linear data structure where elements (called nodes) are stored in a sequence but not in contiguous memory locations as in the case of arrays. Each node contains:
- Data
- A pointer (or reference) to the next node
Visualize it as a chain – each link (node) knows where the next link is.
Linked List in Data Structures and Algorithms
Stacks, queues, graphs and many more can be built using linked lists in DSA. Linked lists are very useful since they are capable of dynamic memory allocation unlike arrays which have to be of a set size.
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Types of Linked Lists
Understanding the types of linked lists helps in selecting the right one based on your use case.
1. Singly Linked List
Each node points to the next node.
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[Data | Next] → [Data | Next] → NULL
- Easy to implement
- Used for simple linear traversal
2. Doubly Linked List
Every vertex points to both the previous and the next vertex.
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NULL ← [Prev | Data | Next] ↔ [Prev | Data | Next] → NULL
- Allows traversal in both directions
- Slightly more memory due to extra pointer
3. Circular Linked List
The last node connects back to the first node.
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[Data | Next ] → …→ [Data | Next] ↻ (points back to the head)
- Useful for cyclic data processing like round-robin scheduling
Each of these has its strengths. For example, circular linked list usage is common in applications where the list needs to be accessed in a loop.
Common Operations in Linked List
Let’s go through the core actions you can perform:
Insertion and Deletion in Linked List
These are the two main operations. Linked lists allow inserting or deleting elements:
- At the beginning
- At the end
- In the middle (at a given position)
Unlike arrays, you don’t need to shift elements.
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# Basic insertion at head (Python)
class Node:
def __init__(self, data):
self.data = data
self.next = None
def insert_at_head(head, data):
new_node = Node(data)
new_node.next = head
return new_node
Linked List Traversal Techniques
Traversing means moving from one node to the next. For singly linked lists, this is done in one direction. You are able to go both ways in doubly linked lists.
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# Traversing a singly linked list
def traverse(head):
while head:
print(head.data)
head = head.next
Linked List vs Array Performance
Choosing between a linked list and an array depends on what you need.
| Feature | Array | Linked List |
| Memory allocation | Fixed | Dynamic |
| Insertion at front | O(n) | O(1) |
| Deletion at front | O(n) | O(1) |
| Random access | O(1) | O(n) |
| Cache friendliness | High | Low |
Advantages of Linked List Over Array
- No fixed size — grows dynamically
- Efficient insertions and deletions
- No need to shift elements
- Useful for implementing stacks, queues, and graphs
When to Use Linked List Over Array?
Use linked lists when:
- Frequent insertions/deletions are required
- You don’t know the size of the dataset in advance
- You’re building data structures like stacks or queues
How to Implement Linked List in Python
Here’s a full example of a simple singly linked list:
python
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class Node:
def __init__(self, data):
self.data = data
self.next = None
This is how each node in a simple singly linked list looks.
self.data = data
self.next = None
self.head = None
class LinkedList:
def init(self):
self.head = None
def insert(self, data):
new_node = Node(data)
new_node.next = self.head
self.head = new_node
def print_list(self):
current = self.head
while current:
print(current.data)
current = current.next
# Usage
ll = LinkedList()
ll.insert(10)
ll.insert(20)
ll.print_list() # Output: 20 -> 10
This example shows the best way to learn linked list — by coding and practicing each operation step-by-step.
Real-Life Use Cases of Linked List
Now, let’s explore real-world applications of linked list across industries.
In Software Development
- Implementing dynamic memory structures like stacks, queues, hash tables
- Undo/redo functionality in text editors (Doubly Linked List)
- Browser history navigation (Back and Forward buttons)
In Data Science
- Sparse matrices use linked lists for efficient memory usage
- Graphs and adjacency lists often use linked list representations
- Log streaming and data preprocessing pipelines
In Operating Systems
- Memory management and CPU scheduling
- Linked list of processes/threads
In Non-Tech Applications
- Playlist organization in music apps
- Navigation systems (Linked nodes represent checkpoints)
- Ticket reservation systems where customer entries are queued
These show the wide scope of real-life use cases of linked list.
Is Linked List Important for Coding Interviews?
Absolutely!
Many linked list data structure interview questions are asked by top tech companies. Some examples include:
- Detect cycle in a linked list
- Reverse a linked list
- Merge two sorted linked lists
- Remove N-th node from end
- Find the middle node
Linked List Questions for Beginners
Start with:
- Insert at beginning/end
- Delete a node
- Traverse and print list
- Search for an element
Once you’re comfortable, move to advanced problems like singly vs doubly linked list operations, circular lists, and recursion-based manipulations.
Why Learn Linked Lists?
Here’s why you must master this concept:
- It teaches pointer manipulation and memory management
- It’s used in many real-world systems
- It’s tested in almost every coding interview
- It helps build complex structures like stacks, queues, graphs, and more
Step-by-Step Guide to Linked List
- Start with theory: Understand what a node and pointer is
- Learn to implement: Use Python or C++ to build basic operations
- Visualize it: Use diagrams or animation tools to see traversal
- Practice: Solve beginner to advanced problems
- Apply: Use linked lists in projects like building your own queue
That’s the best way to learn linked list — by blending theory with hands-on coding.
Conclusion
The linked list data structure explained here is a core part of every software developer’s toolkit. Whether you’re a student, a coding beginner, or a professional, understanding this structure helps in interviews, projects, and real-world problem solving.
At Sharpener Tech, we help learners master data structures like linked lists with a practical, job-focused approach. Our Pay After Placement programs in Full Stack Development and Data Science & Analytics ensure you learn deeply — and only pay when you land a high-paying job.
So, get started today, and take the first step toward mastering data structures and algorithms!
