Coding Interview Q&A

What is the difference between an Array and a Linked List?

What is a Stack and where is it used?

Explain the difference between a Queue and a Deque.

What is a Binary Search Tree (BST)? What are its time complexities?

What is a Hash Table? How does it handle collisions?

What is a Heap? Explain Min-Heap and Max-Heap.

What is the difference between BFS and DFS graph traversal?

What is a Trie (Prefix Tree) and when would you use it?

What is a Graph? Explain adjacency matrix vs adjacency list.

What is a Balanced Binary Tree? Name some self-balancing trees.

Compare Merge Sort and Quick Sort.

What is Binary Search? What are its prerequisites?

What is Dynamic Programming? Explain with an example.

What is a Greedy Algorithm? When does it fail?

Explain Dijkstra's Shortest Path Algorithm.

What is the Two-Pointer technique? Give an example.

What is the Sliding Window technique?

What is Topological Sort? When is it used?

What is the difference between Recursion and Iteration?

What is the Knapsack Problem? Explain 0/1 vs Fractional.

What is the difference between a Process and a Thread?

What is a Deadlock? What are the four necessary conditions?

Explain CPU scheduling algorithms: FCFS, SJF, Round Robin.

What is Virtual Memory? How does paging work?

What is a Semaphore? How does it differ from a Mutex?

What is Thrashing in operating systems?

What is the difference between Preemptive and Non-Preemptive scheduling?

What is a Context Switch?

Explain the Producer-Consumer problem.

What is the difference between internal and external fragmentation?

What are ACID properties in a database?

What is Normalization? Explain 1NF, 2NF, 3NF, BCNF.

What is the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL JOIN?

What is an Index? What are its types?

What is the difference between DELETE, TRUNCATE, and DROP?

What is a Transaction? Explain COMMIT and ROLLBACK.

What is the difference between SQL and NoSQL databases?

What is a View in SQL? What are its advantages?

What are aggregate functions in SQL? Give examples.

What is a Stored Procedure vs a Function in SQL?

What are the 7 layers of the OSI model?

What is the difference between TCP and UDP?

What happens when you type a URL in a browser?

What is subnetting? How do you calculate subnet masks?

What is the difference between HTTP and HTTPS?

What is DNS? How does DNS resolution work?

What is the difference between a Hub, Switch, and Router?

What is NAT (Network Address Translation)?

What is the TCP 3-way handshake?

What are common HTTP status codes?

What are the four pillars of OOP?

What are SOLID principles?

What is the Singleton design pattern?

What is the Observer design pattern?

What is the difference between Abstract Class and Interface?

What is the Factory design pattern?

What is method overloading vs method overriding?

What is Dependency Injection?

What is the difference between composition and inheritance?

What is the MVC design pattern?

What is a pointer? What is the difference between a pointer and a reference?

What is the difference between stack and heap memory allocation?

What is a virtual function? What is a vtable?

What is RAII (Resource Acquisition Is Initialization)?

What is the STL? Name important containers and their complexities.

What is the difference between struct and class in C++?

What are move semantics and rvalue references in C++11?

What is a memory leak? How do you detect and prevent it?

What is function overloading vs template functions?

What is the difference between `new`/`delete` and `malloc`/`free`?

What is the GIL (Global Interpreter Lock) in Python?

What is a decorator in Python? Write a timing decorator.

What is a generator in Python? How does it differ from a list?

What is the difference between `is` and `==` in Python?

What are *args and **kwargs in Python?

What is list comprehension? Compare with map/filter.

What is the difference between shallow copy and deep copy?

What is asyncio? When would you use it?

What are Python's mutable vs immutable types?

What is the difference between `__str__` and `__repr__`?

What is the CAP theorem?

What is horizontal vs vertical scaling?

What is a CDN (Content Delivery Network)?

What is database sharding?

What is a message queue? When would you use one?

What is caching? What are common caching strategies?

What is a load balancer? What algorithms does it use?

What is the difference between microservices and monolithic architecture?

How would you design a URL shortener (like bit.ly)?

What is eventual consistency vs strong consistency?

What is the memory hierarchy? Why does it exist?

What is CPU pipelining? What is a pipeline hazard?

What is the difference between RISC and CISC architectures?

What is cache coherence in multiprocessor systems?

What is branch prediction? Why is it important?

What is the difference between little-endian and big-endian?

What is DMA (Direct Memory Access)?

What is the difference between synchronous and asynchronous I/O?

What is a TLB (Translation Lookaside Buffer)?

What is Amdahl's Law?