Microsoft Interview Questions and Experience

1. What is the difference between an abstract class and an interface in C#?
   An abstract class can provide both definitions and implementations, while an interface only provides method signatures.
2. How would you reverse a linked list in place?
   By iterating through nodes and changing next pointers, using constant space and O(n) time complexity.
3. Explain garbage collection in .NET.
   Garbage collection automatically manages memory by reclaiming objects no longer in use, preventing memory leaks.
4. How do you detect a cycle in a directed graph?
   Use depth-first search with a recursion stack or Kahn’s algorithm for topological sorting.
5. What is the difference between managed and unmanaged code?
   Managed code runs under the .NET CLR, while unmanaged code runs directly on the OS without CLR support.
6. How would you implement a LRU cache?
   By combining a doubly linked list with a hash map to achieve O(1) insertion and retrieval.
7. What are delegates in C#?
   Delegates are type-safe function pointers used for event handling and callback methods.
8. How do you handle database deadlocks?
   By using transaction isolation levels, deadlock detection, retry logic, or breaking long transactions into smaller ones.
9. What is multithreading and how is it handled in C#?
   Multithreading enables concurrent execution using Thread, Task, and async/await patterns in C#.
10. How would you design a URL shortener like bit.ly?
    Use hash functions or base62 encoding, database sharding for scalability, and caching for fast retrieval.
11. Explain dependency injection in .NET Core.
    Dependency injection provides loose coupling by supplying required dependencies at runtime rather than hardcoding them.
12. What is the difference between value type and reference type in C#?
    Value types store data directly in memory, while reference types store memory addresses pointing to data.
13. How would you test the performance of a REST API?
    Use load testing tools like JMeter or Apache Bench, monitor latency, throughput, and error rates under stress.
14. What are design patterns you commonly use?
    Examples include Singleton for global state, Factory for object creation, and Observer for event-driven programming.
15. How do you optimize SQL queries in a large-scale database?
    By creating indexes, analyzing execution plans, normalizing tables, and reducing unnecessary joins.

Fresher / Intern Roles

1. What is the difference between stack and queue?
   Stack follows LIFO, while queue follows FIFO for element access.
2. How would you check if a string is a palindrome in C#?
   By comparing characters from both ends moving inward, or by reversing the string and checking equality.
3. What are the pillars of Object-Oriented Programming?
   Encapsulation, Abstraction, Inheritance, and Polymorphism.

Software Engineer / Developer Roles

1. How do you implement dependency injection in ASP.NET Core?
   By registering services in Startup.cs with AddTransient, AddScoped, or AddSingleton methods.
2. What is the difference between SQL Server and Azure SQL Database?
   SQL Server is an on-premise solution, while Azure SQL is a managed cloud service with built-in scaling and security.
3. How do you debug a memory leak in a .NET application?
   By using tools like Visual Studio Profiler or dotMemory to analyze heap allocations and uncollected objects.
4. How would you handle real-time data streaming in Azure?
   By using Azure Event Hubs, Stream Analytics, and Azure Functions for ingestion, processing, and storage.
5. What is the difference between Azure Functions and Azure Logic Apps?
   Azure Functions focus on serverless code execution, while Logic Apps focus on workflow automation with minimal coding.

Data / Business Analyst Roles

1. How would you optimize a slow-running SQL query?
   Check indexes, reduce nested queries, and review query execution plans for bottlenecks.
2. What is the difference between OLTP and OLAP systems?
   OLTP handles day-to-day transactions, while OLAP is used for analytical processing and reporting.
3. How would you validate data quality in a reporting system?
   By using constraints, profiling tools, and reconciliation against source data.

Program / Project Manager Roles

1. How do you prioritize conflicting tasks across multiple teams?
   By assessing impact, urgency, dependencies, and aligning decisions with business goals.
2. How do you apply Agile methodology in managing projects?
   By using sprints, backlog grooming, daily stand-ups, and iterative delivery of features.
3. What metrics would you track in a large software project?
   Velocity, defect density, cycle time, customer satisfaction, and system uptime.
4. How do you handle disagreements between developers on a technical approach?
   Encourage open discussion, evaluate trade-offs, and make data-driven decisions while maintaining team cohesion.

1. Tell me about a time you had to resolve a conflict in your team.
   Discuss how you listened to both sides, mediated effectively, and ensured the project continued smoothly.
2. How do you handle working under tight deadlines?
   Share examples where you prioritized tasks, stayed organized, and communicated clearly to deliver results on time.
3. Describe a situation where you took ownership of a project.
   Explain how you identified gaps, proposed solutions, and led execution while keeping stakeholders informed.
4. Give an example of when you received critical feedback. How did you handle it?
   Show that you accepted the feedback positively, applied improvements, and demonstrated growth in your next task.
5. How do you ensure effective collaboration in a cross-functional team?
   Mention practices like open communication, regular updates, shared goals, and respecting diverse perspectives.
6. Tell me about a time when a project did not go as planned. What did you do?
   Highlight how you identified issues early, adapted the approach, and minimized impact while keeping stakeholders aligned.
7. How do you stay aligned with Microsoft’s values of innovation and inclusion?
   Describe how you foster creativity, support diverse perspectives, and ensure your work has a positive impact.
8. Why do you want to work at Microsoft, and how do you see yourself contributing?
   Focus on Microsoft’s culture of innovation, opportunities for growth, and how your skills align with their mission.

Candidate Background

Fresher from a tier-3 engineering college, passionate about software development. Applied via Microsoft Careers after finding the off-campus internship opening on LinkedIn.

Interview Process They Faced

• Written Test: 2-hour online assessment with 4 DSA problems (graphs, DP, arrays). Solved 3 fully, 4th partially.
• Round 1 (Technical Interview): Included self-introduction, project discussion, and coding problems. Asked to implement queue operations using arrays, linked list, and circular linked list.

Questions Asked

• Self-introduction, favorite subject, project explanation.
• Queue implementation (array, linked list, circular linked list).
• Follow-up: difference between arrays and linked lists.
• Edge case handling and reasoning for conditions.

Outcome & Difficulty Level

Despite performing well in the written and technical round, final status showed “Not Selected”. Difficulty level: Moderate, with strong focus on DSA and project explanation.

Candidate Background

Experienced software engineer with a B.Tech in CSE from Institute of Aeronautical Engineering, Hyderabad. Worked with C/C++, Python, Bash, and YANG, with hands-on project experience in networking systems.

Interview Process They Faced

• Round 1 (Online Coding): Codility test with easy-to-medium coding challenges.
• Round 2 (Technical Interview): Coding problems on linked lists and arrays.
• Round 3 (Low-Level Design): Implementing a logging framework with dynamic log levels and appenders.
• Round 4 (High-Level Design): Designing the classic Snake game.
• Round 5 (Hiring Manager): Mix of coding, resume-based project discussions, and behavioral questions.

Questions Asked

• Reverse a linked list in groups of K nodes.
• Find the majority element (appearing more than n/2 times).
• Implement a logging framework (support levels, appenders, dynamic changes).
• Design Snake game (system design).
• Word chaining problem: last three characters of a word must match first three of the next.
• Resume-based project deep dive + HR questions.

Outcome & Difficulty Level

Successfully cleared all rounds and was offered the Microsoft SDE role. Difficulty level: Moderate to Hard, with balanced focus on coding, design, and behavioral skills.