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After covering the foundational building blocks in Session 1, the next step is one of the most important problem-solving techniques in all of programming: recursion . And once recursion feels comfortable, it unlocks a powerful search strategy called backtracking . These two concepts appear everywhere in competitive programming — Fibonacci, binary search, tree traversal, merge sort, dynamic programming, N-Queens, and more. They deserve their own spotlight. 🌟 What Is Recursion? A function is recursive if it calls itself. Instead of solving a problem in one go, a recursive function breaks it into a smaller version of the same problem, solves that, and repeats — until the problem becomes simple enough to answer directly. Three things define every recursive solution: The problem is expressed in terms of a smaller instance of itself Each call reduces the problem size There is a point where the problem becomes trivial and no further calls are needed — this is the base case The Nested Box Analogy Think of recursion like opening nested boxes. A big box contains a smaller box, which contains another, and so on. Eventually you find the item you were looking for. That innermost box is the base case. Without it, you would keep opening boxes forever — which is how you get a stack overflow, not a solution. Base Case and Recursive Case Every recursive function has exactly two parts: Recursive case — the problem is reduced in size and the function calls itself again. Base case — the terminating condition. No further recursive call is made. The function returns a direct answer. Both are non-negotiable. A function without a base case will keep calling itself, consuming stack memory until the program crashes. Example: Factorial 5! = 5 × 4! 4! = 4 × 3! 3! = 3 × 2! 2! = 2 × 1! 1! = 1 ← base case Each step reduces the problem by one. When the function hits 1! = 1 , it stops, and the results unwind back up the call stack. In pseudocode: function factorial(n): if n == 1: return 1 # base cas

AI Fluency for Software Engineers: A Practical Playbook Beyond Prompting A few years ago, being productive with AI mostly meant knowing which tool to open and what question to ask. Today, that is not enough. For software engineers, AI is no longer just a chatbot sitting outside the workflow. It is becoming a thinking partner for architecture decisions, code reviews, production incidents, documentation, test planning, onboarding, and product discovery. But there is a problem: many teams are using powerful AI tools with weak operating habits. They ask vague questions. They paste too much context. They trust the first answer. They forget privacy boundaries. They use AI for speed, but not always for better engineering judgment. That is where AI fluency matters. AI fluency is not just prompt engineering. It is the ability to work with AI clearly, safely, and practically while staying in control of quality, reasoning, and responsibility. Here is a practical playbook I would recommend for software engineers and engineering teams. 1. Start with clarity, not clever prompts A weak prompt sounds like this: “Review this design and tell me if it is good.” The AI can answer, but the answer will likely be generic. A stronger prompt gives the AI a clear role, context, constraints, and output format: You are a senior backend architect. Review this proposed API design for a high-traffic order processing system. Evaluate: - correctness - scalability - failure handling - observability - backward compatibility - operational complexity Do not rewrite the whole design unless required. Separate critical risks from optional improvements. Output format: - Executive summary - Key risks - Recommended changes - Open questions - Final decision recommendation The difference is not word count. The difference is control. A fluent AI user does not hope the AI understands the task. They make the task hard to misunderstand. 2. Give enough context, but not everything AI output quality depends heavily o

Competitive programming often looks like a race to write code as fast as possible. But the real secret is simpler: the best competitive programmers are not just faster typists — they are better at choosing the right data structure, the right algorithm, and the right complexity level for the job. Before we jump into recursion, dynamic programming, graphs, or those problems that make your brain do backflips, we need a solid base. This first session is exactly that. Let's begin. 🚀 1. Data Types: What Kind of Data Are You Storing? A data type tells a programming language what kind of value a variable holds and what operations are valid on it. Primitive Data Types The basic building blocks provided by the language itself: Integer — whole numbers: 5 , 100 , -3 Float / Double — decimal values: 3.14 , 99.5 Character — a single symbol: 'A' , 'z' Boolean — true or false User-Defined Data Types When primitive types are not enough, programmers define their own: Structs — group related fields under one name Classes — structs with behaviour (methods) attached Enums — a fixed set of named constants Typedefs / Aliases — rename existing types for clarity A Real-World Example Imagine building a food delivery app: An integer stores the number of items in the cart A float stores the total bill amount A boolean tracks whether the order has been delivered A class represents an entire Order — customer name, address, items, payment status Data types are essentially the labels on your containers. Without them, chaos begins early. 2. Data Structures: How Do You Organise Data? If data types answer what a value is, data structures answer how to organise many values efficiently. This is where competitive programming starts to get interesting. Linear Data Structures Elements arranged one after another, like people queuing at a ticket counter: Arrays — fixed-size, indexed, fast random access Linked Lists — dynamic size, efficient insertions and deletions Stacks — last in, first out (LIFO) Queues

The first message ever sent across the network that became the internet was not "Hello, world." It was not a grand declaration. It was two letters, transmitted by accident, before the system fell over: LO . That two-letter packet is the ancestor of every connected device, every IoT sensor, and every web request running today. The story of how it happened is also a surprisingly useful lesson for anyone building embedded systems and connected hardware right now. What actually happened on October 29, 1969 On the evening of October 29, 1969, a programmer named Charley Kline sat at a terminal in Leonard Kleinrock's lab at UCLA. His job was simple on paper: log in to a remote computer at the Stanford Research Institute (SRI), roughly 350 miles away, over a brand-new experimental network called ARPANET. The plan was to type the command LOGIN . The remote machine at SRI was set up to auto-complete the rest once it saw the first few characters, so Kline only needed to start typing. He had a colleague on the phone at the Stanford end to confirm each letter arrived. He typed L . Stanford confirmed: "Got the L." He typed O . Stanford confirmed: "Got the O." He typed G - and the SRI system crashed. So the first message ever transmitted over ARPANET was "LO." As Kleinrock later liked to point out, it was an accidental but fitting first word: "LO" as in "lo and behold." About an hour later they fixed the bug and completed the full login, but the historic first packet had already gone out, two letters at a time. Why a crash is the perfect origin story It is tempting to read this as a cute footnote. It is more than that. The very first thing the internet ever did was fail partway through a transaction - and the system was built well enough that the humans on both ends knew exactly how far it had gotten before it died. That is the entire discipline of networked systems in miniature. Connections drop. Remote machines crash mid-request. Packets arrive out of order, or not at all. The n

A short essay on why the developer community should invest as much effort as possible into LLMs that are free from corporations and states. ML researchers and hardware engineers both need to contribute here. The latter may even be more important, because whether users can run advanced LLMs on personal hardware depends on breaking NVIDIA's monopoly. This essay is highly political, especially in the opening sections. Keep that in mind. Corporate AI Will Be Closed and Unaccountable by Default The other day, almost at the same time as the release of Fable 5, Anthropic's Dario Amodei published an article called "Policy on the AI Exponential", where he discussed what the world should do with powerful AI-based systems. All sections except the first contain fairly reasonable proposals, or at least proposals worth discussing. I will not consider them here. The real core is in the first section. In that first section, he effectively proposes a system in which the state would be required to license advanced AI systems, measured by the amount of compute used, and even ban the release of models that are not considered safe for society. In practice, this repeats a story as old as the world: a large corporation wants to regulate the market so smaller companies do not interfere with its ability to earn mountains of money, all under noble-sounding pretexts. And the point is not that Amodei is some villain. He is simply an entrepreneur who wants to earn as much money as possible. Any large corporation would prefer not to let smaller companies near the feeding trough in its field. Anthropic is merely saying this openly, and that is all. In effect, AI Big Tech wants a future where all non-AI companies become its serfs, mortally dependent on intelligence delivered through Anthropic's API, or OpenAI's, or Google's, and so on. In practice, those AI companies would hold the revenue of all these other companies in their hands. Without them, the whole economy around those companies would cru

Strip the noise, Disrupt the bug. Discussion | Link

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The company made its heavily anticipated debut on Friday, trading higher than its initial $135 IPO price.

Find the odd tile before the clock runs out Discussion | Link

If you're thinking about upgrading your phone, "the best time was yesterday," according to Nothing CEO and co-founder Carl Pei, echoing a message we heard during MWC. As Android Authority reports, Pei said in a post on X that the RAM shortage has already impacted Nothing's less expensive mid-range phone: "For Phone 4A , memory […]

See the aircraft flying over you on a retro radar scope Discussion | Link

A SpaceX-Tesla merger seems inevitable.

Vulnerability in the Oracle-owned PeopleSoft software is about as critical as they come.

Section 702 of FISA to expire tonight, but certification lasts until March 2027.

When you build Shopify apps or integrations, pagination becomes important very quickly. A small test store may have a few products and orders. A real merchant store can have thousands of products, variants, orders, customers, inventory items, metafields, and fulfillment records. You cannot fetch all of that data in one Shopify GraphQL request. You need pagination. More importantly, you need pagination that performs well. Poor Shopify GraphQL pagination can create slow syncs, API throttling, timeout errors, duplicate processing, and incomplete exports. This post explains how Shopify GraphQL pagination works and how to handle large Shopify datasets in a practical way. What Shopify GraphQL Pagination Solves Pagination lets your app retrieve data in smaller chunks. Instead of asking Shopify for 50,000 products at once, your app asks for 100 or 250 products per request. Shopify returns the data and gives your app information about the next page. This protects your app from huge responses and protects Shopify from heavy requests. It also gives your integration more control over retries, progress tracking, and background processing. Shopify Uses Cursor-Based Pagination Shopify GraphQL uses cursor-based pagination. That means you do not request data using page numbers. You request the next page using a cursor from the previous response. A basic product pagination query looks like this: query GetProducts ( $cursor : String ) { products ( first : 100 , after : $cursor ) { nodes { id title handle updatedAt } pageInfo { hasNextPage endCursor } } } The first time you run this query, pass cursor as null. Shopify returns the first 100 products and gives you an endCursor . Use that endCursor as the after value in the next request. Keep doing this until hasNextPage is false. Why Cursors Work Better Than Page Numbers Offset pagination usually works like this: page=1 page=2 page=3 or: offset=5000&limit=100 This approach becomes inefficient when datasets grow. The system may need to sk

JSON and GraphQL dominate modern web development, but XML (eXtensible Markup Language) is far from obsolete. Enterprise integrations, legacy systems, healthcare standards, and financial protocols still rely heavily on XML. If you work across diverse stacks, understanding XML is a skill that pays dividends. This guide covers the core syntax, validation techniques, parsing approaches, and best practices - with code you can put to work right away. Why XML Still Matters in 2026 XML has been around since 1996 and continues to thrive in specific domains. It handles deeply nested hierarchical data well, supports robust native schema validation, and manages mixed document-oriented content better than most alternatives. If you're dealing with SOAP APIs, Android layouts, SVG, DOCX/XLSX files, HL7 healthcare records, or FIX financial protocols, you're already in XML territory. The Core Building Blocks of an XML Document At its core, XML is a tree of nodes serialized as text. Every well-formed document starts with a declaration that tells the parser the version and character encoding - UTF-8 is the standard choice. From there, the document is composed of nested elements, attributes, and optionally text content. Elements - The Tree Nodes Elements are the primary structural unit in XML. They wrap your data in opening and closing tags. XML is case-sensitive, so a tag and a tag are treated as two completely different elements. Every opened element must have a corresponding closing tag to keep the document well-formed. Attributes - Metadata on Elements Attributes sit inside an opening tag and carry metadata about the element rather than the primary data itself. A good rule of thumb: use attributes for identifiers, types, or units (like currency), and use child elements for the actual payload data. This separation keeps your parsers predictable and your document structure clean. Self-Closing Elements When an element has no content or child nodes, you can collapse the open and close t

A decision memo for anyone staring at their package.json and wondering. Most arguments for leaving your SPA framework center on the upgrade treadmill — the endless cycle of major-version migrations, dependency churn, and build-tool turnover. That argument is real but incomplete, and on its own it has never been decisive: every framework shop has learned to live with the treadmill. There's a stronger case, built on four pillars that compound with each other. First, total cost of ownership : vanilla JavaScript on the web platform has unusual TCO properties, dominated by a depreciation curve that is nearly flat. Code written against the platform does not rot, because its substrate does not change. Over long horizons, this single property outweighs almost every per-feature productivity argument in a framework's favor. Second, the labor market : the pool of people who can work on vanilla JavaScript is not a niche within the frontend market — it is the entire frontend market, plus most of the backend market. Every framework developer is, underneath, a JavaScript developer. The reverse is not true. If you hire for a specific framework, you're hiring from a subset while telling yourself you're hiring from the mainstream. Third, AI leverage : engineers now produce a growing share of code with AI assistance, and the economics of that assistance differ sharply by target. The web platform is a small, stable, exhaustively documented body of knowledge; a framework ecosystem is a large, fast-mutating one whose training data is perpetually stale. AI coding tools are measurably more reliable on the former. As AI-assisted development becomes the dominant mode of production, the substrate that AI handles best becomes the cheaper substrate — and the gap widens every year the platform stays still while frameworks move. Fourth, architecture : porting to Web Components is not a transliteration of the same design into different syntax. The platform pushes toward a genuinely different archi

It isn't the only startup tackling physical AI, but it's one of the best-funded.

TL;DR: HTML-first means shipping real, server-rendered content before any JavaScript runs, then adding scripts only where they earn their place. In 2026 this approach is winning again, not out of nostalgia, but because the median mobile page now ships around 646 KB of JavaScript, fewer than half of mobile sites pass Core Web Vitals, and the browser already does natively what many sites still pull in libraries for. For most business websites, progressive enhancement is faster to ship, cheaper to run, and easier to keep alive. Sometime in 2026, "just use HTML" stopped being a contrarian take. I noticed it first in my own client work, not in a conference talk. The sites that start close to the platform, plain HTML, forms, links, server rendering, and add JavaScript only where it genuinely helps, are the ones that launch faster, load cleaner, and generate fewer confused support messages two months later. This is not anti-JavaScript. It is a reaction to a decade of reaching for a framework before asking whether the project needed one. The pendulum is swinging back toward the browser, and the numbers explain why. What HTML-first actually means (and why it is not 2009 web design) The fastest way to misunderstand this is to picture table layouts and inline styles. That is not it. HTML-first is an order of operations. You build a page that is complete and usable as server-rendered HTML, then you enhance it. The content is readable before a single script loads. The form submits even if JavaScript never arrives. This is the old idea of progressive enhancement , applied deliberately with modern tools instead of by accident. There is a small but real movement around this now. The HTML First community manifesto argues, fairly, that the platform has far more capability than most teams use. You do not have to agree with every line of it to notice the shift. The point is not to ban JavaScript. The point is to stop treating it as the default starting material for every page. The 2026

Há alguns meses, pagando $7/mês por um servidor de 512MB no Render pra hospedar uma API de um projeto da escola, decidi entender como esse tipo de infraestrutura funciona por baixo — e construir a minha própria versão. O resultado é o Arctis Deploy : uma plataforma de deploy contínuo via Git, com Docker isolado por projeto. Esse post é sobre como ela funciona por dentro. Arquitetura geral Frontend (Next.js) │ ▼ Backend (Go + Fiber) — Clean Architecture │ ├──► Deploy-Agent (roda em cada servidor) → Docker └──► Database-Agent (provisiona MySQL/Postgres) em desenvolvimento, ainda não disponível para usuários Cada servidor de produção roda um deploy-agent próprio. O backend central envia comandos via HTTPs autenticado e o agent executa o que for necessário — clone, build, container, métricas. O pipeline de deploy Todo deploy passa por 5 etapas sequenciais: clone — git clone --depth 1 , otimizado pra trazer só o necessário analyze — detecta o framework automaticamente lendo package.json , requirements.txt , go.mod , etc. build — gera um Dockerfile multi-stage específico pro framework detectado (timeout: 15min) deploy — sobe o container na porta alocada, com limites de CPU/RAM aplicados health check — faz requisições até o container responder, com rollback automático em caso de falha Cada etapa emite logs estruturados ( info / warn / error ), transmitidos via WebSocket em tempo real pro frontend. Detecção automática de framework Next.js, React, Vue, Node.js, e sites estáticos. A detecção é baseada nos arquivos do repositório — o usuário só conecta o Git e dá push. Outros detalhes Pool de recursos : cada plano define um total de Projetos/CPU/RAM/disco que o usuário distribui livremente entre seus projetos Auto-sleep : no free, containers sem tráfego são pausados ( docker pause ) — não destruídos — e despertam automaticamente na próxima requisição Domínios : subdomínio automático ou domínio próprio, com SSL via Cloudflare Pagamentos : MercadoPago integrado, planos em real V