Interview Prep
Real questions for real interviews. C#, Python, Go. Junior → System Design.
Quiz me →C# / .NET
Mid-level
- How does async/await work under the hood in C#? What is the state machine?
- Implement a generic LRU Cache with O(1) get and put operations
- What is the difference between IEnumerable<T> and IQueryable<T>?
- What is dependency injection (DI) and how does ASP.NET Core's built-in container work?
- Explain delegates, Func, Action, and events in C# — when do you use each?
- Merge overlapping intervals from a list of [start, end] pairs
- Tell me about a time you significantly improved the performance of a system
- What is middleware in ASP.NET Core and how is the pipeline composed?
Python
Mid-level
- What is the GIL in CPython and when does it limit performance?
- Implement a memoization decorator in Python
- What are context managers in Python and how do you implement one with __enter__ and __exit__?
- Implement a retry decorator with configurable attempts and exponential backoff
- Tell me about a time you optimised a slow Python service in production
- Design a Python service for processing real-time user activity events with rate limiting
Go
Mid-level
- Explain Go's error handling pattern. When should you use panic and recover?
- Implement a concurrent worker pool in Go
- Tell me about a time you improved the reliability or performance of a production system
- What is the context package in Go and how do you use it for cancellation and deadlines?
- Explain the select statement in Go — how does it multiplex channels?
- Implement a context-aware system design for a real production challenge you've faced