GitHub Repos That Helped You Clear the Exams: A Curated Study Stack
The coding exams and technical interviews that matter are won before you sit down. These are the open-source study repos that do the heavy lifting.
Ask any engineer what actually got them through their exams or technical interviews, and the answer is rarely a single textbook. It is a repository—curated, opinionated, and often more current than any syllabus. Here are the GitHub repos that show up again and again when people clear the hardest CS exams, certification rounds, and FAANG-style interviews.
1. The structured grind: coding-interview-university
John Washam's [coding-interview-university](https://github.com/jwasham/coding-interview-university) is a full computer science curriculum compressed into a daily study plan. It covers data structures, algorithms, operating systems, networking, and interview behavior. The repo works because it forces you to treat preparation as a program, not a mood.
2. The algorithm library: The Algorithms
[The Algorithms](https://github.com/TheAlgorithms) is a collection of implementations across Python, Java, C++, Go, and more. It is not a place to copy-paste. It is a reference for seeing how a binary search, segment tree, or dynamic programming pattern looks in idiomatic code. Use it after you have attempted the problem yourself.
3. The systems primer: system-design-primer
Donne Martin's [system-design-primer](https://github.com/donnemartin/system-design-primer) is the closest thing to a systems design textbook on GitHub. It includes a study guide, flashcards, real-world architecture diagrams, and a framework for discussing tradeoffs. This is essential for design rounds and advanced software engineering exams.
4. The interview handbook: tech-interview-handbook
Yangshun's [tech-interview-handbook](https://github.com/yangshun/tech-interview-handbook) is a practical companion for the final stretch. It has cheat sheets, behavioral question templates, resume guidance, and a curated problem list. It is more about execution than deep theory.
5. The dense notes: CS-Notes
[CS-Notes](https://github.com/CyC2018/CS-Notes) by CyC2018 is a dense, well-organized set of notes on algorithms, operating systems, networks, databases, and Java. It reads like a distilled exam syllabus and is particularly strong for CS fundamentals.
6. The pattern finder: leetcode-patterns
Sean Prashad's [leetcode-patterns](https://github.com/SeanPrashad/leetcode-patterns) groups LeetCode problems by underlying pattern: sliding window, two pointers, dynamic programming, graph traversal. Recognizing the pattern is more valuable than memorizing the problem.
7. The visual learner: hello-algo
[hello-algo](https://github.com/krahets/hello-algo) is an open-source, illustrated data structures and algorithms book. The diagrams and animations make abstract topics concrete. It is especially useful for visual learners and for revisiting fundamentals without friction.
8. The builder's route: build-your-own-x
[build-your-own-x](https://github.com/codecrafters-io/build-your-own-x) curates tutorials for building small versions of real tools: databases, shells, compilers, network protocols. The act of building is the fastest way to internalize systems knowledge and produce something examiners can see.
How to use these repos without drowning
Pick one structured plan as your spine. Use The Algorithms and CS-Notes as references. Track problem patterns from leetcode-patterns. Revisit system-design-primer weekly. Build one small project from build-your-own-x for each major subject. The goal is not to collect stars—it is to convert open-source knowledge into your own working memory.
At Sapior, we think the best developer tools and the best study repos share a core trait: they remove friction before it becomes procrastination.