Algorithms & Data Structures

What it does

Algorithms with TypeScript is a free online textbook covering algorithms and data structures. The book spans 22 chapters across six parts, including sorting, dynamic programming, graph algorithms, trees, heaps, and hash tables. Each algorithm is implemented in idiomatic TypeScript 5 with complexity analysis, exercises, and a full test suite using Vitest. The content is available as a web-based book that can also be downloaded as a PDF.

Who it is for

The book targets two main audiences. Software engineers seeking to refresh or fill gaps in their understanding of algorithms and data structures, particularly those who want to learn using TypeScript rather than pseudocode or other languages. Computer Science students taking algorithms courses who benefit from seeing implementations they can run and modify. The book assumes basic familiarity with TypeScript or JavaScript but no prior algorithms knowledge; it starts from first principles and builds up through an MIT-equivalent curriculum.

Pricing

The book is free. The site does not display any pricing or premium tiers.

How it stands out

The primary differentiator is the TypeScript implementation focus. Most algorithms texts use pseudocode, Java, Python, or C++. By using TypeScript, the book appeals to the large population of web developers for whom algorithms often feel disconnected from daily work. The implementations are tested, idiomatic, and type-safe rather than academic translations. The author also took an unusual production approach: the first few chapters were written manually over a decade-long span, then abandoned. Recently, the remaining chapters were completed using AI assistance (Zenflow and Claude) under a spec-driven workflow. This hybrid human-AI authorship is disclosed openly.

What a founder should check

A founder considering a competing product should verify three things. First, the incumbent landscape: books like Cracking the Coding Interview, Introduction to Algorithms, and language-specific resources (like Python or JavaScript algorithm guides) already dominate. What pricing, positioning, or feature would displace them? Second, switching costs and reach. This book is free, which eliminates price-based competition but also revenue. If a paid alternative offered interactive coding environments, live feedback, or mentoring, would students pay? Third, the moat in completeness. The book claims equivalence to MIT's undergraduate algorithms courses and covers standard topics. Once freely available, incremental improvements (better explanations, more exercises, or interactivity) become the only advantage—and those are easy for others to copy. The quality of AI-assisted content and its long-term accuracy under maintenance should also be tested.