Most Asked Infosys SP & DSE Interview Questions — With Explanations

Programming & DSA Questions

These are the core focus areas, especially for SP.

Question	Explanation
Implement Fibonacci using recursion & dynamic programming	Checks ability to optimize brute-force code with memoization or tabulation.
Reverse a linked list / reverse in K-groups	Tests linked list manipulation and pointer handling.
Detect and remove cycle in a linked list	Determines understanding of Floyd’s Cycle Algorithm & memory handling.
Longest common subsequence / substring	A standard DP problem that examines complexity optimization thinking.
Implement Binary Search Tree (insert, search, delete)	Verifies your foundation in tree structures and recursive logic.
Implement quick sort / merge sort and give time complexity	Evaluates algorithmic understanding and divide-and-conquer approach.
Kadane’s algorithm (maximum subarray sum)	Shows ability to work with greedy techniques and edge cases.
Sliding window problem (like longest substring without repeating characters)	Tests approach on window resizing and hashing for frequency count.
N-Queens problem	Examines backtracking skills and recursive branching logic.
Travelling Salesman Problem (TSP)	Used to test thinking in DP + bitmasking / brute-force pruning.

SP candidates should expect advanced DSA
DSE candidates should expect DSA + small implementation-based problems

More focused for SP, but asked to both.

Question	Explanation
Difference between abstraction, encapsulation, inheritance & polymorphism	Basic OOPS pillar understanding.
Method overloading vs overriding	Core runtime vs compile-time polymorphism question.
What is SOLID design principle?	Tests awareness of clean code and scalable software design.
What is a virtual function & pure virtual function?	Practical OOPS implementation test in languages like C++/Java.
Define constructor and destructor & their types	Examines class lifecycle understanding.
What is multithreading? What are race conditions & thread-safety?	Evaluates concurrency handling knowledge.
Explain stack vs heap memory	Checks memory model understanding and debugging efficiency.
What is garbage collection?	Evaluates ability to understand memory management in Python/Java.

Frequently asked for both SP & DSE.

Question	Explanation
What are the different types of joins?	Must know INNER/LEFT/RIGHT/FULL joins usage.
What is ACID property in DBMS?	Shows understanding of reliability & transactional systems.
Normalize a database up to 3NF	Tests modeling skills and reduction of redundancy.
Difference between primary key, unique key & foreign key	Fundamental relational database concept check.
What is indexing? Clustered vs non-clustered?	To check performance tuning understanding.
What is trigger, view & stored procedure?	Tests real-world SQL optimization & code modularity.

Question	Explanation
Explain REST API and HTTP request methods	Verifies server-client architecture fundamentals.
Difference between PUT, POST and PATCH	Checks API update logic understanding.
Explain MVC architecture	Evaluates structured development experience.
How JWT authentication works?	Assesses security and session management knowledge.
What is CI/CD?	Tests automation and deployment pipeline understanding.
Docker vs Kubernetes	Measures familiarity with containerization & orchestration.
What is microservices architecture?	Tests modern scalable system knowledge.

Asked in every SP & DSE interview.

Question	Explanation
Explain your project architecture and tech stack	Confidence check on real-world work.
What problem does your project solve & why is it needed?	Checks problem-solving ability & business thinking.
What was your role in the project?	Ensures authenticity — not copied work.
What challenges did you face and how did you solve them?	Shows learning ability and crisis handling.
Which algorithm/data structure did you implement in your project and why?	Connects project to DSA foundation.

Tip: You should be able to draw the project flow logically on paper or verbally.

Although HR elimination is low, attitude matters.

Question	Explanation
Tell me about yourself	Sets first impression — must align skills with the job.
Why do you want to join Infosys?	Checks interest in company, not just job.
Relocation / Night shifts availability	Assesses job flexibility.
Why should we hire you?	Tests confidence + self-awareness + career clarity.