Designing a URL shortener
A step-by-step way to answer the classic system design question: requirements, API, short codes, storage, caching and scaling.
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Merge sort, step by step
How merge sort splits, sorts and merges; why it is O(n log n); and when to choose it.
Authentication and authorization in ASP.NET Core
Schemes, cookies vs tokens, CSRF, policies with handlers, Identity details and the mistakes interviewers ask about.
Grid problems: flood fill
How to walk a grid in four directions, stay inside the bounds, and count connected areas.
Merge sort, step by step
How merge sort splits, sorts and merges; why it is O(n log n); and when to choose it.
Making microservices resilient
Timeouts, retries with backoff, circuit breakers, idempotency and the outbox: how services survive each other's failures.
Dependency injection in ASP.NET Core
Why DI exists, how to register services, the three lifetimes, and the mistakes interviewers ask about.
Designing a URL shortener
A step-by-step way to answer the classic system design question: requirements, API, short codes, storage, caching and scaling.
Sorting cheat sheet
Costs, memory and stability of the common sorts, and what C#'s built-in sorts really do.
Concurrency in .NET: which tool when
A one-page map of .NET's concurrency tools, with the bugs each one prevents.
Monolith vs microservices
What each architecture is, the real trade-offs, and how to answer the classic interview question.
Designing a URL shortener
A step-by-step way to answer the classic system design question: requirements, API, short codes, storage, caching and scaling.
Dependency injection in ASP.NET Core
Why DI exists, how to register services, the three lifetimes, and the mistakes interviewers ask about.
Concurrency in .NET: which tool when
A one-page map of .NET's concurrency tools, with the bugs each one prevents.
Data structures: which one when?
A one-page cheat sheet: what each basic data structure is good at, what it costs, and the C# type to use.
Concurrency in .NET: which tool when
A one-page map of .NET's concurrency tools, with the bugs each one prevents.
Merge sort, step by step
How merge sort splits, sorts and merges; why it is O(n log n); and when to choose it.
Tree traversals
The four ways to visit a tree, when each one is useful, and how much memory they need.
Designing a URL shortener
A step-by-step way to answer the classic system design question: requirements, API, short codes, storage, caching and scaling.
Authentication and authorization in ASP.NET Core
Schemes, cookies vs tokens, CSRF, policies with handlers, Identity details and the mistakes interviewers ask about.