Dreaming of landing your ideal role as a Software Engineer at a top tech company? Whether you’re a fresher or preparing for your next career move, interviews can be challenging—but with the right preparation, you can stand out.
This blog provides a comprehensive list of the most frequently asked Software Engineer interview questions, complete with clear, concise answers to help you prepare with confidence.
1. Data Structures & Algorithms (DSA)
Core Topics: Arrays, Linked Lists, Strings, Hashing, Sliding Window, Recursion, Dynamic Programming
Reverse a Linked List (Iterative)
Reverse a Linked List (Recursive)
Find the Missing Number in an Array
Detect a Cycle in a Linked List (Floyd’s Algorithm)
Merge Two Sorted Linked Lists
Implement Binary Search
Find the Largest Element in an Array
Two Sum Problem (Hashing)
Check if a String is a Palindrome
Longest Substring Without Repeating Characters
Implement a LRU Cache
This is often implemented using a HashMap and Doubly Linked List or using Python’s OrderedDict.
Practice Platforms: LeetCode, CodeStudio, GeeksforGeeks
2. Object-Oriented Programming (OOP)
Four Pillars of OOP
Encapsulation: Hiding internal data using private access modifiers.
Abstraction: Exposing only essential features of an object.
Inheritance: Creating a new class using the properties of an existing class.
Polymorphism: Performing a single action in different ways.
Abstract Class vs Interface
| Feature | Abstract Class | Interface |
|---|---|---|
| Method Body | Can have body | Only declarations |
| Inheritance | Single | Multiple allowed |
| Constructor | Yes | No |
Method Overloading vs Method Overriding
Overloading: Same method name, different parameters. Happens at compile time.
Overriding: Subclass redefines a method from the superclass. Happens at runtime.
Constructor and Destructor
Constructor: Initializes an object.
Destructor: Cleans up when an object is destroyed (in Python:
__del__).
Real-World Example
A class Vehicle with subclasses Car and Bike demonstrates inheritance, where each subclass can override methods like startEngine() (polymorphism).
Learning Resources: JavaTpoint, TutorialsPoint
3. Database Management System (DBMS)
What is Normalization and Denormalization?
Normalization: Organizing data to reduce redundancy.
Denormalization: Adding redundancy to improve read performance.
SQL vs NoSQL
SQL: Structured data, relational databases like MySQL.
NoSQL: Unstructured data, document/key-value stores like MongoDB.
ACID Properties
Atomicity: All steps complete or none.
Consistency: Valid data state maintained.
Isolation: Transactions do not interfere.
Durability: Changes are permanent after commit.
Index in SQL
Indexes improve search performance by allowing quick access to data rows.
Primary Key vs Unique Key
Primary Key: Unique and not null.
Unique Key: Uniqueness enforced, null values allowed.
SQL Query for Second Highest Salary
Practice Platforms: LeetCode SQL, W3Schools SQL
4. System Design Basics
How Does URL Shortening Work?
Hash the URL, store it in a database.
Generate a unique short key that redirects to the original URL.
Designing Uber’s Ride-Matching System
Use real-time geo-location data.
Match nearby riders and drivers using pub-sub architecture.
What is Load Balancing?
Evenly distributes incoming network traffic across multiple servers.
How Does a CDN Work?
Delivers content from geographically closer servers to improve speed.
Monolithic vs Microservices Architecture
Monolithic: Single large codebase.
Microservices: Multiple smaller, independent services.
Learning Resource: GitHub’s System Design Primer
5. Operating System & Computer Networks
Process vs Thread
Process: Independent unit of execution.
Thread: Subset of a process that shares memory.
Deadlock and Prevention
Occurs when processes wait for each other indefinitely.
Avoid using resource ordering, timeouts, and safe allocation algorithms.
What Happens When You Enter a URL?
DNS resolution → TCP/HTTP request → Server response → Webpage rendered
TCP vs UDP
| TCP | UDP |
|---|---|
| Reliable | Unreliable |
| Slower | Faster |
| Ordered delivery | No guarantee |
Virtual Memory and Paging
Virtual Memory: Extension of physical memory using disk.
Paging: Divides memory into fixed-size blocks for efficient access.
How Does DNS Work?
Translates domain names into IP addresses via DNS resolvers and authoritative servers.
Learning Resources: CS50, Operating Systems by Galvin
Bonus Tips to Crack Software Engineer Interviews
Solve 100+ DSA problems from platforms like LeetCode and CodeForces.
Build real-world projects and contribute to open-source.
Revise core CS subjects regularly.
Practice mock interviews on platforms like Pramp and InterviewBit.
Use the STAR Method (Situation, Task, Action, Result) to structure answers.
Conclusion
Preparation is the key to success. Mastering these common interview questions and concepts will significantly boost your confidence and performance. Focus on solving problems, understanding the fundamentals, and practicing effective communication.
Stay consistent, keep learning, and go crack that dream job.
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