Advanced Technical Round Questions

Advanced Technical Round Questions for Experienced Candidates

In any comprehensive hiring process, understanding the expectations of  Advanced Technical Round Questions is essential for candidates aiming to secure technical roles. The advanced technical round typically focuses on challenging problems that test deep technical knowledge, problem-solving skills, system architecture understanding, and coding proficiency.

This guide emphasizes preparing for the Advanced Technical Round Questions by presenting over 30 recent and frequently asked questions. These questions cover algorithms, data structures, system design, concurrency, and language-specific challenges. Mastering these questions will help you confidently tackle the advanced technical interview phase and impress your interviewers.

1. How do you find the longest substring without repeating characters?

Use the sliding window technique with two pointers and a hash map to track characters. Expand the right pointer while characters are unique and move the left pointer when duplicates occur. Keep track of the maximum window size.

2. Explain the difference between a process and a thread.

A process is an independent executing program with its own memory space, while a thread is a lightweight subunit of a process sharing the same memory. Threads allow concurrent execution within the same process, enabling efficient multitasking.

3. Write code to detect a cycle in a linked list.

Use Floyd’s Cycle Detection Algorithm (Tortoise and Hare). Use two pointers moving at different speeds; if they meet, a cycle exists.

4. Describe the differences between TCP and UDP protocols.

TCP is connection-oriented, reliable, and ensures ordered delivery, suitable for applications like HTTP. UDP is connectionless, faster, but does not guarantee delivery or order, used in streaming and gaming.

5. How would you implement a thread-safe singleton pattern?

Use double-checked locking with a volatile instance variable or initialize the singleton instance in a static initializer to ensure thread safety without performance overhead.

6. Explain how garbage collection works in managed languages like Java.

The garbage collector automatically frees memory occupied by objects no longer reachable. It uses algorithms like Mark-and-Sweep, Generational collection, and can run concurrently or stop-the-world based on JVM implementation.

7. How do you handle deadlocks in concurrent systems?

Prevent deadlocks by avoiding circular wait, using lock ordering, applying timeouts on locks, or employing deadlock detection algorithms to recover or roll back transactions.

8. Implement an LRU Cache and explain its time complexity.

Use a combination of a doubly linked list and a hash map. The linked list maintains order of usage, and the map provides O(1) access. Insert and retrieval both run in constant time.

9. What is the difference between optimistic and pessimistic locking?

Pessimistic locking assumes conflicts happen and locks resources immediately, blocking others. Optimistic locking assumes conflicts are rare and checks for conflicts before commit, retrying if necessary.

10. How do you design a concurrent producer-consumer queue?

Use thread-safe data structures or implement synchronization with condition variables or semaphores to coordinate producers and consumers without data races.

11. What is memoization and how is it used to optimize recursive algorithms?

Memoization caches the results of expensive function calls and returns cached results for repeated inputs, significantly improving recursive algorithm efficiency, such as in Fibonacci number calculations.

12. Explain CAP theorem and its relevance in distributed systems.

The CAP theorem states that a distributed system can simultaneously provide only two of three guarantees: Consistency, Availability, and Partition tolerance. Design choices depend on which guarantees are prioritized.

13. Write a function to serialize and deserialize a binary tree.

Use preorder traversal for serialization, encoding null nodes explicitly, and during deserialization, reconstruct the tree by reading values in order.

14. Describe how you would implement a deadlock detection algorithm.

Model resource allocation as a wait-for graph and detect cycles using graph traversal algorithms like DFS. When cycles are found, deadlocks exist.

15. How do you ensure thread safety when updating shared data?

Use synchronization primitives like mutexes, locks, atomic operations, or higher-level abstractions such as concurrent collections to prevent race conditions.

16. Implement an algorithm to find the median of two sorted arrays.

Use a binary search approach to partition arrays, ensuring logarithmic time complexity.

17. What are the pros and cons of monolithic vs microservices architecture?

Monolithic architectures are simpler to develop but harder to scale and maintain. Microservices enable modular development and scaling but introduce complexity in deployment and inter-service communication.

18. How does garbage collection impact application performance?

Garbage collection can introduce latency pauses, especially in stop-the-world collectors. Modern collectors minimize this with concurrent and incremental techniques but tuning is often necessary.

19. How do you implement a thread pool? What are its advantages?

A thread pool maintains a fixed number of threads to execute tasks, reusing threads to reduce overhead. It improves resource management and system throughput.

20. Explain how you would secure a REST API.

Use HTTPS, authentication (OAuth, JWT), input validation, rate limiting, logging, and apply the principle of least privilege to safeguard endpoints.

21. What is a race condition and how can you prevent it?

A race condition occurs when multiple threads access shared data concurrently without synchronization. Prevent it by using locks, atomic operations, or immutable data.

22. Describe the difference between synchronous and asynchronous programming.

Synchronous programming waits for tasks to complete sequentially, potentially blocking. Asynchronous programming allows other tasks to proceed without waiting, improving resource utilization and responsiveness.

23. How would you implement a priority queue?

Use a binary heap (min-heap or max-heap) to achieve O(log n) insertion and deletion of highest or lowest priority elements.

24. Explain the producer-consumer problem and provide a solution outline.

It involves synchronizing producer and consumer threads sharing a buffer. Use semaphores or mutexes to ensure producers don’t overflow and consumers don’t consume empty buffers.

25. Write code to reverse a linked list both iteratively and recursively.

Iterative: Use three pointers (prev, current, next). Recursive: Reverse the rest of the list and fix links accordingly.

26. What is a deadlock and how do you avoid it?

Deadlock occurs when processes wait indefinitely for each other’s resources. Avoid it by ensuring resource ordering, using timeout locks, or avoiding hold-and-wait conditions.

27. How do you design a scalable notification service?

Use asynchronous message queues, support multiple notification channels, implement user preferences, and apply rate limiting.

28. What is the difference between optimistic and pessimistic concurrency control?

Optimistic concurrency assumes low conflict and verifies changes before commit. Pessimistic concurrency locks resources upfront to prevent conflicts.

29. How would you design a high-throughput logging system?

Use append-only log storage, distributed brokers like Kafka, batch writes, and partition data to avoid bottlenecks.

30. Explain how load balancing works and list some algorithms used.

Load balancers distribute client requests across servers to optimize resource use. Algorithms include Round Robin, Least Connections, IP Hash, and Weighted Distribution.

31. How do you debug a multi-threaded application?

Use thread dumps, logging with thread IDs, specialized debuggers supporting concurrency, and look for deadlocks or race conditions.

Final Tips for By Interview Round Advanced Technical Round Questions

Preparing for the By Interview Round Advanced Technical Round Questions requires consistent practice, clear understanding of fundamentals, and effective communication of your thought process. Focus on problem-solving patterns, system design principles, and concurrency concepts, as these are often emphasized in senior-level interviews. Furthermore, explaining your code and design decisions confidently will distinguish you from other candidates and increase your chances of success.