Infosys Specialist Programmer Interview Experience (2 Rounds) | OA + Technical Interview | Selected

• Company: Infosys
• Role: Specialist Programmer
• Interview Mode: Online Assessment + On-site Interview
• Difficulty Level: Medium to Hard
• Result: Selected
• Interview Timeline: Within 1 Week

The recruitment process consisted of two rounds:

1. Online Assessment (Coding Round)
2. Technical Interview

Overall, the interview process was well structured and primarily focused on Data Structures & Algorithms (DSA), Object-Oriented Programming (OOP), problem-solving skills and coding fundamentals.

Round 1 : Online Assessment

• Duration: 180 Minutes
• Difficulty: Medium to Hard

The first round was an online coding assessment consisting of three programming problems. The overall difficulty was on the harder side.

• Two problems were Hard-level DSA questions.
• One problem was of Medium difficulty.

To qualify for the next round, candidates needed to solve at least two questions completely, ensuring that both visible and hidden test cases passed successfully. The problems required optimized solutions rather than brute-force approaches and covered different algorithmic concepts.

Question 1 : Modified Sliding Window

The first problem was based on the Sliding Window technique but introduced additional constraints that made it significantly more challenging than the standard pattern.

The solution required:

• Maintaining an optimal window.
• Handling multiple constraints simultaneously.
• Updating the window efficiently while preserving optimal time complexity.

A strong understanding of sliding window variations was essential for solving this problem.

Question 2 : Two-Dimensional Dynamic Programming

The second problem focused on 2D Dynamic Programming. The interviewer expected candidates to:

• Define appropriate DP states.
• Identify state transitions correctly.
• Optimize both time and space complexity whenever possible.

Candidates with solid Dynamic Programming fundamentals would find this question manageable.

Question 3 : Bit Manipulation

The final coding question tested Bit Manipulation concepts. The problem required using bitwise operators efficiently to achieve an optimized solution. Knowledge of common bit manipulation techniques such as:

• Bit masking
• XOR operations
• Left and right shifts
• Setting and clearing bits

proved useful while solving the question.

Round 2 : Technical Interview

• Duration: 60 Minutes
• Difficulty: Medium

The technical interview was conducted on-site and was comparatively easier than the online assessment. The interviewer began with a discussion about:

• My resume
• Academic background
• Projects
• Programming experience
• Preferred programming languages

After the introduction, the discussion shifted toward technical concepts and coding questions.

Coding Question 1 : Evaluate a Postfix Expression

The interviewer asked me to evaluate a given Postfix Expression.

Discussion

I explained how a Stack can be used to:

• Read the expression from left to right.
• Push operands onto the stack.
• Pop operands whenever an operator is encountered.
• Perform the operation.
• Push the result back onto the stack.

After explaining the approach, I implemented the solution and discussed its time and space complexity.

Coding Question 2 : Convert Postfix Expression to Infix

The next coding problem involved converting a Postfix Expression into its equivalent Infix Expression.

The solution again required using a Stack.

The interviewer mainly focused on:

• Correct logic
• Proper handling of operator precedence
• Appropriate placement of parentheses
• Clean implementation

After discussing the approach, I completed the implementation successfully.

Conceptual Question : Acid Properties

Apart from programming questions, I was also asked a simple conceptual question regarding the properties of acids.

The discussion was straightforward and appeared to assess basic academic knowledge rather than advanced technical expertise.

All Interview Questions

• Modified Sliding Window problem
• Two-Dimensional Dynamic Programming problem
• Bit Manipulation problem
• Evaluate a Postfix Expression
• Convert Postfix Expression to Infix
• Basic question on Acid Properties
• Resume discussion
• Object-Oriented Programming (OOP) concepts

Overall Experience

Overall, the interview experience was smooth, professional and positive. The Online Assessment was considerably more difficult than the technical interview and served as the primary elimination round. Strong problem-solving skills, particularly in Dynamic Programming, Sliding Window and Bit Manipulation, were essential for clearing this stage.

The Technical Interview was more discussion-oriented and focused on coding fundamentals, Data Structures, Object-Oriented Programming concepts, resume-based discussions and problem-solving ability. The interviewer was supportive and gave me sufficient time to explain my approach before implementing the solutions. I was delighted to receive the selection after successfully completing both rounds.

Preparation Tips

Based on my experience, here are a few suggestions for future candidates:

• Build a strong foundation in Data Structures and Algorithms.
• Practice Dynamic Programming extensively, as it is frequently tested in the Online Assessment.
• Revise commonly used techniques such as:
  • Sliding Window
  • Bit Manipulation
  • Stacks
  • Queues
  • Trees
• Solve coding problems under time constraints to improve speed and accuracy.
• Practice stack-based expression problems, including:
  • Postfix Evaluation
  • Prefix Evaluation
  • Infix to Postfix Conversion
  • Postfix to Infix Conversion
• Revise Object-Oriented Programming concepts thoroughly.
• Prepare to discuss your projects in detail and explain the technologies you have used.
• If you are comfortable with multiple programming languages such as Java, C++, or Python, mention them during the interview, as it demonstrates versatility.

Advice for Future Candidates

The Online Assessment is the most competitive stage of the Infosys Specialist Programmer hiring process. Focus on solving at least two coding problems completely, ensuring that every visible and hidden test case passes.

Manage your time effectively during the assessment. If a problem appears too difficult, avoid spending excessive time on it and move to the next question. Consistent practice with medium and hard-level DSA problems, combined with a solid understanding of core computer science concepts, can significantly improve your chances of success in the Infosys Specialist Programmer recruitment process.