Complete textbooks — not summaries — written from courses actually taught, and released free in both English and Indonesian. Each title covers a full semester: chapter by chapter, with worked problem sets placed at the checkpoints where they matter.

• 2026 M.M. Irfan Subakti (2026) AI Programming Tutorial: From Zero to Building 100 Applications with Python. profitina.com.

  A hands-on journey through one hundred complete Python applications, from a first chatbot and spreadsheet cleaner to everyday machine-learning tools — price and demand forecasting, document and image classification, recommendation, speech, computer vision and retrieval-augmented assistants built on local models — each explained step by step, running, tested and ready to adapt to your own work, so that by the last chapter you can build real AI products rather than toy demos. Read more →

• 2026 M.M. Irfan Subakti (2026) Framework-Based Programming: ASP.NET Core, Laravel and Spring Boot, from First Route to Deployed App. profitina.com.

  Sixteen chapters that take one real business application — Profitina Laundry — through the three frameworks the industry actually uses: routing, controllers and views, ORMs and migrations, validation, authentication and authorization, REST API design, testing and deployment in ASP.NET Core, Laravel and Spring Boot, side by side, with four Evaluation-and-Discussion chapters, sixteen lectures and a hundred-question bank, so you learn the patterns behind every framework, not just one framework’s syntax. Read more →

• 2026 M.M. Irfan Subakti (2026) Fundamental Programming with C, C++ and Python. profitina.com.

  The first programming course, told from the very beginning: how a computer runs a program, then variables, decisions and loops, functions and recursion, arrays, pointers, strings, structures, files, and finally C++ classes — every program given in C or C++ and again in Python with identical output, grown around a small laundry’s cashier system, with sixteen lectures, a hundred worked questions and four chapters that solve complete problems the way an expert would. Read more →

• 2026 M.M. Irfan Subakti (2026) Human-Computer Interaction: Designing Usable, Accessible and AI-Ready Interfaces, with Java and Python. profitina.com.

  A completely renewed guide to designing interfaces people love, current to 2026: human perception and memory, design principles, user research, prototyping, usability testing with SUS and A/B experiments, design systems, mobile and voice interaction, accessibility under WCAG 2.2 and new regulations, ethical and privacy-respecting UX, designing chat, copilot and agent interfaces, analytics, and spatial and wearable computing — with Java and Python tools, sixteen lectures and a hundred-question bank. Read more →

• 2026 M.M. Irfan Subakti (2026) Numerical Methods: From Error Analysis to Machine Learning, with Java and Python. profitina.com.

  Sixteen chapters that show how computers actually compute: floating-point errors, root finding, linear systems and matrix decompositions, interpolation and curve fitting, differentiation and integration, differential equations, eigenvalues, optimization and the numerical heart of machine learning, ending with fast parallel computation and a complete simulation — every method derived, hand-worked on everyday problems, programmed in Java and Python, checked against NumPy and SciPy, and accompanied by sixteen lectures and a hundred-question bank. Read more →

• 2026 M.M. Irfan Subakti (2026) Intelligent Systems: Building Smart Applications for Everyday Life, from Zero. profitina.com.

  Fifteen chapters that turn the classic ideas of artificial intelligence into useful everyday applications anyone can follow — rule-based advisors, forward and backward chaining, confidence factors, Ripple Down Rules, fuzzy logic, genetic algorithms and a local-LLM shop assistant — each built step by step in both Java and Python for real situations such as a street vendor’s restock plan, a first-aid guide, a durian orchard advisor, fair pricing and delivery routes. Read more →

• 2026 M.M. Irfan Subakti (2026) Variable-Centered Intelligent Rule System: Building Expert Systems That Learn, from Zero to Real Applications. profitina.com.

  The author’s own research method, made practical: an expert system that learns case by case, weighs its variables and rules by how they are used, and generates new rules on its own — explained from zero and built into fifteen real applications, from a Wi-Fi troubleshooter and a study-program advisor to a clinic triage knowledge base, a web app with a database, rules learned from data and a local-LLM front end, all running on one shared engine in Java and Python. Read more →

• 2026 M.M. Irfan Subakti (2026) Competitive Programming with SPOJ. profitina.com.

  Fourteen chapters that take you from your very first submission to a steady stream of “Accepted”: reading a problem the way the judge does, picking an algorithm from the constraints, fast I/O, compiler flags, memory budgets, and the classic traps behind Wrong Answer, then dynamic programming, greedy proofs, binary search on the answer, graphs, number theory, geometry and strings — every idea proven on real SPOJ problems with fresh, stress-tested C++17 and Python code. Read more →

• 2026 M.M. Irfan Subakti (2026) Informatics Olympiad (OSN): Road to National Champion — 15 SPOJ Case Studies. profitina.com.

  Fifteen chapters of olympiad training for students who already know the basics and aim to become a national champion — a medal, an honourable mention or a place in the final: each session dissects a contest-grade problem end to end — breakdown, complexity, the full algorithm — and hands half of the code to you, so that training becomes the execution discipline that actually wins medals. Read more →

• 2026 M.M. Irfan Subakti (2026) Data Structure. profitina.com.

  Sixteen chapters that make memory visible — arrays, searching and sorting, stacks and queues, pointers, singly, doubly and circular linked lists, recursion, trees and binary search trees, graphs, heaps and hash tables — each drawn state by state, every program given in C++, Java, and Python with identical output, and four Evaluation-and-Discussion chapters that solve full problems the way an expert would. Read more →

• 2026 M.M. Irfan Subakti and Rully Soelaiman (2026) Design and Analysis of Algorithms. profitina.com.

  The theoretical backbone of computer science in sixteen chapters: modelling a problem precisely, designing an algorithm, proving it correct and measuring how its cost grows — from asymptotics and recurrences through divide and conquer, dynamic programming, greedy methods, graph algorithms, shortest paths and flows to NP-completeness, with every idea implemented and verified in C++. Read more →

• 2026 M.M. Irfan Subakti (2026) Object-Oriented Programming. profitina.com.

  Sixteen chapters that turn “writing code” into “designing software”: classes and objects, encapsulation, inheritance, polymorphism, interfaces, generics, exceptions, collections, files, GUIs, design patterns and testing — one running system grown chapter by chapter, with every program in Java and Python and four chapters of fully worked evaluation problems. Read more →

• 2026 M.M. Irfan Subakti (2026) Profitina: Building an AI Visibility Platform in the Open. profitina.com.

  The public engineering story of Profitina, an AI-visibility (GEO) platform: why brands must now be found by ChatGPT, Gemini and Perplexity, and how such a platform is designed, built, measured and operated — architecture, data pipelines, measurement, product and business decisions — written openly so students and founders can learn from a real product in the making. Read more →

• 2026 M.M. Irfan Subakti (2026) Profitina Laundry. profitina.com.

  One small laundry business, built for real, end to end: customers, orders, services, receipts, payments, reports and a JSON API — the same complete application developed side by side in PHP, Java, Python and ASP.NET Core, so you see how a real business system is modelled, coded, tested and shipped in every major stack. Read more →

• 2026 M.M. Irfan Subakti (2026) Web Programming. profitina.com.

  Sixteen chapters on how the web really works, from the moment you press Enter: HTML, CSS and JavaScript, PHP with MySQL, XML and JSON, Java Server Pages and ASP.NET Core — each feature built three or four ways side by side, growing one complete Profitina Laundry web app with login, orders, payments, dashboards and an API. Read more →

• 2018 M.M. Irfan Subakti (2018) Sistem Cerdas. profitina.com.

  The 2018 edition of the intelligent-systems text: expert systems, forward and backward chaining, certainty factors, Ripple Down Rules, fuzzy logic and genetic algorithms — the foundation of the brand-new 2026 edition that turns each method into a practical everyday application in Java and Python. Read more →