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How to Decompose a Legacy Java Monolith Without Disrupting Business Operations The Java monolithic applications have been supporting businesses for years. In these applications, the entire business logic, presentation layer, and data access layer are bundled into a single unit. These architectures are functional but hard to scale, maintain, and improve due to changing business needs. An expert Java app development company helps growing organizations in addressing this issue through Java modernization services. Instead of developing a whole software application from scratch, firms can transform their software in stages with the right boundaries. The biggest challenge here is to determine where to make those cuts in a bundle. Poorly chosen service boundaries create operational complexity issues and long-term maintenance problems. Understanding how to identify seams in the monolith application helps in achieving modernization successfully. Let's take a look at what contributes to the success of monolith decomposing and how organizations can approach it wisely. Why Organizations Are Modernizing Legacy Java Monoliths The legacy Java monolith applications were built during a time when monolithic architecture was common. They were optimized for easy deployment and centralized management. But today, businesses require flexibility. This is due to challenges such as Slow release cycles Increasing maintenance costs Limited scalability Complex dependency management Difficult onboarding new developers Growing technical debt These issues have increased the demand for software architecture modernization in business sectors. Modern architecture gives the following advantages to the teams: Deploy features independently Scale services individually Improve system resilience Accelerate development cycles Support cloud-native environments The objective of architecture modernization is to create a technical foundation that supports future business growth. Understanding business goals of

After a full week of intensive Bitcoin programming training, the developers at Zone01 Kisumu moved into the most exciting phase of the bootcamp: building real-world solutions powered by Bitcoin, the Lightning Network, and LND. One thing I learned throughout the experience is that the human mind is truly fascinating. The room was filled with innovative ideas, each attempting to solve a different problem. As the saying goes, no idea is a bad idea—every concept had the potential to make an impact. A total of 17 teams were formed, and each team embarked on a 24-hour hackathon journey to transform their ideas into working products. After an intense day of development came the presentation phase, where we had the privilege of showcasing what we had built. Our team developed Kasi , a WhatsApp chatbot that enables Bitcoin transactions directly through WhatsApp. The goal was to make Bitcoin payments more accessible by leveraging a platform that millions of people already use daily. To build Kasi, we integrated the Twilio API for WhatsApp communication and utilized the Bitnob platform to facilitate Bitcoin transactions. Python was used throughout the development process. The project was brought to life by six developers: Claire, Lamka, Ijay, Dishon, Talo, and myself. Beyond the technical implementation, the hackathon strengthened our understanding of collaborative software development. We practiced Git workflows, team coordination, version control, task management, and effective communication under tight deadlines—skills that are just as valuable as writing code. Although we did not finish at the top of the leaderboard, the experience was incredibly rewarding. Every team brought something unique to the table, and the winners fully deserved their recognition. Congratulations to all the teams that participated and showcased their creativity, determination, and technical skills. One moment from the presentation will stay with me for a long time. As we were demonstrating Kasi to

A smart contract does not need an overflow, reentrancy bug, or broken access-control check to lose money. Sometimes, the exploit is hidden inside an ordinary division: uint256 result = amount * rate / SCALE; The expression looks harmless. It may even produce the expected answer in every unit test. But financial smart contracts operate with integer arithmetic. Fractions are discarded, rounding direction changes who receives value, and an error of one unit can be repeated across thousands of transactions. In a financial protocol, rounding is not merely a mathematical implementation detail. Rounding is a value-transfer policy. Every division should therefore answer three questions: Which direction does the calculation round? Which party benefits from that direction? Can the rounding advantage be repeated or amplified? This article examines the most dangerous precision problems in Solidity and the engineering patterns used to prevent them. Solidity Does Not Have Native Fixed-Point Arithmetic Most financial formulas use fractions: interest = principal × rate × time fee = amount × fee percentage shares = assets × total shares ÷ total assets collateral value = token amount × oracle price Solidity primarily performs these calculations with integers. For unsigned integers: uint256 result = 5 / 2; The result is: 2 The fractional component is discarded. For positive values, this behaves like rounding down: 2.5 → 2 This appears insignificant until the result represents: vault shares; debt; collateral; protocol fees; interest; rewards; liquidation bonuses; exchange rates; token prices. The lost fraction does not disappear economically. One party receives less value, while another party retains the remainder. Precision Loss Is Not Always Small Consider a protocol calculating a percentage: function calculateFee( uint256 amount, uint256 feeBps ) public pure returns (uint256) { return amount * feeBps / 10_000; } For a 0.3% fee: amount = 100 feeBps = 30 fee = 100 × 30 ÷ 10,000 fee =

The crypto platform claims you can “pay anyone to do anything,” from quitting a job on camera to getting a memecoin-themed tattoo. But it mostly seems like people trying to scam each other.

You've heard of Bitcoin. You've maybe heard of the Lightning Network. But what exactly is LND, and why should developers care? Let's break it down — technically, but from the ground up. The Problem: Bitcoin is Superb but Slow Bitcoin's base layer — the blockchain itself — is intentionally slow. Every transaction must be broadcast to thousands of nodes, verified, and bundled into a block that gets mined roughly every 10 minutes . The network handles about 7 transactions per second (TPS). Compare that to Visa's ~24,000 TPS and you quickly see the problem. Bitcoin in its raw form isn't built for buying coffee, splitting a bill, or paying a freelancer in real time. But there's a solution — and it lives on top of Bitcoin. Enter the Lightning Network The Lightning Network is a Layer 2 (L2) payment protocol built on top of Bitcoin. Instead of recording every single payment on the blockchain, it lets two parties open a private payment channel, transact off-chain as many times as they want, and only settle the final balance on-chain when they're done. Think of it like running a tab at a bar: Opening the tab = one blockchain transaction Each round of drinks = instant off-chain payment Closing the tab = one final blockchain transaction The result? Near-instant payments, near-zero fees, and massive throughput — without sacrificing Bitcoin's security. What is LND ? LND stands for Lightning Network Daemon. It's the most widely used implementation of the Lightning Network protocol, built and maintained by Lightning Labs. Key facts for developers: Written in Go 🐹 Exposes a gRPC API (port 10009) and a REST API (port 8080) Controlled via a CLI called lncli Uses macaroons for authentication (think JWT, but for Lightning) Connects to a Bitcoin node (bitcoind or btcd) as its source of truth Other Lightning implementations exist — like Core Lightning (CLN) and Eclair — but LND has the largest developer ecosystem and is the best entry point. How LND Fits Into the Stack Here's the architec

After failing 3 coding interviews, I realized the problem wasn't practice it was how I was practicing. I spent 6 months grinding LeetCode before my first FAANG interview. 400+ problems solved. Every "Blind 75" problem is memorized. I felt ready. Then the interviewer asked a sliding window variation I hadn't seen before. I froze. Drew a blank. Bombed the interview. The problem wasn't that I hadn't practiced enough. The problem was that I had practiced incorrectly. I memorized solutions instead of understanding patterns. I can recite code, but I struggle to adapt when problems change slightly. So I built something different. Introducing AlgoPatterns A pattern-first DSA learning platform with visualizations that actually show you how algorithms work. algopatterns.in What Makes It Different 1. Pattern-First, Not Problem-First Most platforms throw 2000+ problems at you and say, "Good Luck." AlgoPatterns organizes everything around 17 core patterns: Two Pointers Sliding Window Binary Search BFS/DFS Dynamic Programming Backtracking And 11 more... Master the patterns, and you can solve any variation. 2. Visualizations That Actually Help We have 50+ interactive visualizers that show algorithms step-by-step: Watch two pointers converge in real-time See the DP table fill cell by cell Trace BFS spreading level by level Visualize the call stack during recursion Reading code is one thing. Seeing it executed is completely different. 3. Curated, Not Overwhelming 315 hand-picked problems organized by pattern. Each problem includes: Company tags (Google, Amazon, Meta, etc.) Frequency indicators Pattern classification Difficulty rating No more random grinding. Practice the right problems in the right order. 4. Real Code Templates Every pattern comes with: Java templates (copy-paste ready) "When to use" indicators Common mistakes to avoid Key insights from each pattern Who It's For Interview preppers who want to learn patterns, not memorize solutions CS students who find textbook expla

Token economics is not only about token price. It is about designing the rules, incentives, and long-term logic of a Web3 ecosystem. When people start building a Web3 project, they usually focus on the visible parts first. They think about the smart contract, the frontend, the wallet connection, the token launch, the whitepaper, and maybe the community. All of those are important. But there is one part that can decide whether the project survives or fails: Token economics. A project can have clean smart contracts, a nice UI, and strong marketing, but if the token economy is weak, the project can slowly collapse. Users may come only for rewards, early investors may dump, inflation may destroy value, and the token may lose its reason to exist. That is why token economics should not be treated as just a “crypto finance” topic. For developers and Web3 builders, token economics is closer to system design . It defines how value moves inside the ecosystem, how users are rewarded, how supply is controlled, how governance works, and how the project can grow without depending only on hype. What Is Token Economics? Token economics, often called tokenomics , means the design of how a token works inside a project. It answers questions like: Why does this token exist? Who receives the token? How is the token used? How many tokens will exist? How are rewards distributed? When can team and investor tokens unlock? How does the project treasury work? What creates real demand for the token? In simple words, token economics is the rule system behind a token. A token is not only something people buy and sell. In a real Web3 product, a token can be used for payments, staking, governance, access, rewards, collateral, or network fees. If the token has no clear role, it becomes only a speculative asset. That is dangerous because speculation can bring attention, but it cannot support a project forever. Why Developers Should Care Some developers think token economics is only for founders, eco

Dulu, nyari query yang bikin database spike itu bisa makan berhari-hari. Yang nyari capek, yang nge-fix juga capek. Sekarang? Hitungan jam — dan bonusnya, sambil belajar hal baru juga. Ceritanya begini. Kalau kamu pernah kerja di aplikasi yang pakai ORM (Object-Relational Mapping — semacam "penerjemah otomatis" antara code dan database), pasti familiar sama situasi ini: database tiba-tiba lambat, kamu dapet raw query yang jadi biang kerok, tapi di codebase kamu nulis pakai syntax ORM yang bentuknya beda jauh dari SQL mentah itu. Buat yang belum pernah deal sama ORM, bayangin gini: kamu nulis pesan dalam bahasa Indonesia, lalu ada "penerjemah otomatis" yang convert jadi bahasa Jepang sebelum dikirim ke penerima. Suatu hari ada masalah di pesan yang terkirim — tapi kamu cuma bisa lihat versi bahasa Jepang-nya. Nyari bagian mana dari tulisan Indonesia kamu yang bikin terjemahan-nya bermasalah? Itu effort-nya yang bikin pengen balik tidur aja. Sekarang dengan bantuan Kiro, cukup kasih raw query + akses ke codebase, dia otomatis nyari bagian mana di code yang nge-generate query bermasalah itu. Yang dulu butuh berhari-hari, sekarang bisa selesai dalam hitungan jam — dan itu baru tahap investigasi, belum termasuk fixing-nya. Ceritanya Kenapa Bisa Pakai Kiro Akhir-akhir ini lagi aktif pakai Kiro di tempat kerja. Awal tahun lalu kantor dapat credits melalui program Kiro for Startup , jadi ya sekalian dimaksimalkan. Selain buat debug dan explore query di MS SQL Server, kadang pakai Kiro juga buat analisa log AWS CloudWatch — sambil kasih context aplikasi yang running biar analisa-nya lebih akurat dan gak generic. Di tulisan kali ini, saya mau sharing gimana pakai Kiro sebagai partner beberapa minggu terakhir buat improve query performance di aplikasi .NET Core. Kenapa "partner"? Karena Kiro-nya gak boleh langsung akses ke database — jadi wajib melalui perantara saya. Kita discuss, kolaborasi, dan nge-solve bareng. Bukan AI yang dikasih tombol terus disuruh jalan sendiri. Wakt

A few months ago, I didn't expect that I'd be spending my days debugging authentication flows, opening pull requests, analyzing backend architectures, and building a Bitcoin education platform during a hackathon. Yet here we are. What started as curiosity about Bitcoin turned into one of the most intense learning experiences I've had as a builder, and honestly, I wouldn't trade it for anything. This is the story of how I joined Hack4Freedom Lagos 2026, helped build BitPath, contributed to open source, discovered OpenCode, and learned that software engineering is often just solving one problem after another until things somehow start working. How I Ended Up Building in Bitcoin My interest in Bitcoin didn't start from price charts or trading. What attracted me was the builder ecosystem around it. I've contributed to open source before, so I already appreciated the value of collaborative software development. But what stood out about Bitcoin was how deeply open source is woven into the culture. In many ecosystems, open source feels like an option. In Bitcoin, it feels like a foundation. Everywhere I looked, people were building in public, contributing to projects, improving documentation, reviewing code, and helping newcomers find their footing. That environment made me want to participate more deeply. When the opportunity came to join the Hack4Freedom Lagos 2026 hackathon, I said yes. The Project: BitPath Our team worked on BitPath, an AI-powered learn-and-earn platform designed to make Bitcoin education more accessible. The idea was simple: Instead of overwhelming learners with technical concepts, BitPath uses conversational learning experiences, AI tutoring, quizzes, progress tracking, and rewards to help users learn Bitcoin and financial literacy in a more engaging way. Our stack looked something like this: Frontend Next.js TypeScript Tailwind CSS Zustand Backend NestJS PostgreSQL Redis Queue processing Additional Services Google OAuth OpenAI APIs Lightning Network

本記事は、AtCoder Beginner Contest 462 (ABC462) に参加した際の、A〜E問題の復習と解答の備忘録です。コンテスト中に考えた解法の方針や、提出したPythonのコードについて整理しています。 A - Secret Numbers / 実行時間制限: 2 sec / メモリ制限: 1024 MiB / Difficulty: None 配点 : 100 点 問題文 英小文字と数字のみからなる文字列 $S$ が与えられます。 $S$ から数字である文字だけを取り出し、元の順序のまま並べた文字列を求めてください。 制約 $S$ は英小文字と数字のみからなる長さ 1 以上 50 以下の文字列 自分の解答の方針 一文字づつ数字かどうかを判定し、数字のみを配列に入れて出力する。 提出の時には数字かどうかの判定は0-9のどれかに含まれているかを調べたが、解説ではPythonは isdigit() で数値かどうかを調べられるらしい。 提出したコード S = list ( input ()) T = [] for i in range ( len ( S )): if S [ i ] in [ " 1 " , " 2 " , " 3 " , " 4 " , " 5 " , " 6 " , " 7 " , " 8 " , " 9 " , " 0 " ]: T . append ( S [ i ]) print ( "" . join ( T )) B - Gift / 実行時間制限: 2 sec / メモリ制限: 1024 MiB / Difficulty: None 配点 : 200 点 問題文 人 1 から人 $N$ の $N$ 人がギフトを送り合いました。 人 $i$ は人 $A_{i,1}, A_{i,2}, \dots, A_{i,K_i}$ の $K_i$ 人にギフトを送りました。 $i=1,2,\dots,N$ に対し、人 $i$ にギフトを送った人を全て求めてください。 制約 $2 \le N \le 100$ $1 \le K_i \le N-1$ $1 \le A_{i,1} < A_{i,2} < \dots < A_{i,K_i} \le N$ $A_{i,j} \neq i$ 入力される値は全て整数 自分の解答の方針 辞書に人 $i$ と、その人にギフトを送った人の番号をリストとして持つことを考える。 入力で受け取った、ギフトを送った人と送られた人すべてに対して辞書に登録し、結果を出力する。 提出したコード N = int ( input ()) dct = dict () for i in range ( N ): dct [ i + 1 ] = [] for i in range ( N ): A = list ( map ( int , input (). split ())) for j in range ( 1 , A [ 0 ] + 1 ): dct [ A [ j ]]. append ( i + 1 ) for i in range ( N ): print ( " " . join ([ str ( len ( dct [ i + 1 ]))] + list ( map ( str , dct [ i + 1 ])))) C - Not Covered Points / 実行時間制限: 2 sec / メモリ制限: 1024 MiB / Difficulty: None 配点 : 300 点 問題文 2 次元平面上に点 1 から点 $N$ の $N$ 個の点があります。点 $i$ $(1 \le i \le N)$ の座標は $(X_i, Y_i)$ です。ここで、 $X, Y$ はそれぞれ $(1,2,\dots,N)$ の順列であることが保証されます。 左下の頂点を $(0,0)$ 、右上の頂点を $(X_i, Y_i)$ とする $x$ 軸に平行な辺と $y$ 軸に平行な辺のみからなる長方形の内部（辺上を含まない）に点 1 から点 $N$ までの $N$ 個の点をどれも含まないような $i$ の個数を求めてください。 制約 $1 \le N \le 3 \times 10^5$ $1 \le X_i, Y_i \le N$ $X, Y$ はそれぞれ $(1,2,\dots,N)$ の順列 入力される値は全て整数 自分の解答の方針 端から考えたいので、初めに $X$ についてソートする。 $X$ が小さい順に見ていっ​​たとき、現在の点が作る長方形の内部にほかの点が含まれるかどうかは、、これまでに走査した（$X$座標が自身より小さい）点の中に、自身より $Y$ 座標

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

Blazor SSR Gets Client-Side Validation in .NET 11 Preview 5 If you've built Blazor Server-Side Rendering (SSR) forms, you know the pain: a user fills out a form, hits submit, the form posts to the server, the server runs validation, and only then does the user see the "This field is required" message next to the empty email field. That round-trip latency adds up. It breaks the immediacy users expect from modern web apps. .NET 11 Preview 5 fixes this. Blazor SSR forms now get instant, in-browser validation feedback — no server required. The server renders your validation rules as metadata, and Blazor's JavaScript enforces them client-side. Same DataAnnotationsValidator component you already use. Zero code changes needed. Let's break down how it works. Before .NET 11: The SSR Validation Gap In .NET 8 and 9, Blazor SSR rendered HTML on the server and sent it down. Validation only ran server-side — on form submission. If a field was invalid, the whole form posted to the server, came back with validation messages, and re-rendered. Interactive Blazor modes (Server, WebAssembly, Auto) had instant client-side validation because an active SignalR circuit or WASM runtime ran the validation logic locally. But SSR mode — the simplest, most performant option — was left out. The result? Developers who chose SSR Blazor for its simplicity had to choose between: Accepting the laggy validation UX Adding a second JavaScript validation library (and maintaining two validation rulesets) Re-architecting to use an interactive render mode None of these are great options. What Changed in .NET 11 Preview 5 The .NET team shipped two PRs ( #66441 and #66420 ) that bring unobtrusive client-side validation to Blazor SSR forms. The key insight: The .NET model stays the single source of truth. On form render, the server serializes your DataAnnotations validation rules into HTML metadata attributes. Blazor's JavaScript reads those attributes and applies them client-side — the same approach ASP.NET M

https://dsa-life-simulator-frontend.vercel.app"I made a free tool to make DSA practice feel like an RPG — would like feedback from this community"Been grinding DSA for months and it never felt fun. So I built something. What it does: 🏟️ Real-time 1v1 Arena battles against other devs 🧪 Lab to create and publish your own challenges 🏘️ Community Hub to attempt others' challenges 📖 AI writes your weekly coding journey as a life story 🎮 XP, credits, levels, leaderboards Stack: React + Tailwind + Firebase + Node.js + Socket.IO + Groq AI Still early — would genuinely love feedback from people who've felt the pain of traditional DSA prep.

Problem Link - https://leetcode.com/problems/delete-node-in-a-linked-list/ This is one of those interview questions that looks impossible at first. Normally, to delete a node from a Linked List, we need access to the previous node. But in this problem, we're only given the node that needs to be deleted. No head. No previous pointer. So how do we remove it? Let's understand the trick. Problem Statement Write a function to delete a node in a singly linked list. You are not given the head of the list. Instead, you are given only the node that needs to be deleted. Example Input: 4 -> 5 -> 1 -> 9 node = 5 Output: 4 -> 1 -> 9 Initial Thought Normally we delete a node like this: prev.next = node.next But here: We don't have prev We don't have head So the usual deletion approach is impossible. Key Observation Although we cannot delete the current node directly, we can make it look like it never existed. Consider: 4 -> 5 -> 1 -> 9 We need to delete: 5 Instead of removing node 5 , copy the value of the next node into it. 4 -> 1 -> 1 -> 9 Now remove the next node. 4 -> 1 -> 9 The original value 5 has disappeared. Mission accomplished. Intuition Copy the next node's value into the current node. Skip the next node. The current node now behaves as if it was deleted. Since the problem guarantees that the given node is not the tail node, a next node will always exist. Dry Run Input 4 -> 5 -> 1 -> 9 node = 5 Current node: 5 Next node: 1 Step 1 Copy next node value. node.val = node.next.val List becomes: 4 -> 1 -> 1 -> 9 Step 2 Skip next node. node.next = node.next.next List becomes: 4 -> 1 -> 9 Done. Optimal Java Solution class Solution { public void deleteNode ( ListNode node ) { ListNode cur = node . next ; node . val = cur . val ; node . next = cur . next ; } } Even Shorter Version class Solution { public void deleteNode ( ListNode node ) { node . val = node . next . val ; node . next = node . next . next ; } } Complexity Analysis Metric Complexity Time Complexity O(1) Space Comp

This is a submission for the GitHub Finish-Up-A-Thon Challenge What I Built After being abandoned for several months, I have come back to build and complete Claude with LeetCode, which is a DSA learning system that automates daily algorithm education with Claude code directly inside GitHub repo. Every time I submit an accepted solution on Leetcode, the Github workflow fetches my Leetcode account data and commit the problem with the solution to the repo. Claude will then run on a fixed schedule and automatically generates a full structured lecture, covering the DSA topic, brute force through optimal solutions in Python, complexity analysis, and a YouTube video packaged in a GitHub Issue. This project means a lot to me because it merges two things I care about daily: now not only can I solve Leetcode problem, my solution is automatically analyzed by a powerful AI agent mentor. Demo Link to my project: https://github.com/Stewie-pixel/claude-with-leetcode.git Link to my application walkthrough: https://youtu.be/ClWdW3v9JJ0 The Comeback Story At first this was only a project to store the Leetcode questions I have solved. The process required manual pushing the problem to the repo and nothing special. Later I have added the automation workflow to fetch data from my Leetcode account, Claude will be prompted like an experienced dsa mentor from Claude and skill.md file to give a thorough analysis on that problem. And at the end of the day, Github Copilot workflow will give a daily summary report to cover my daily progress. My Experience with GitHub Copilot I built a DSA Mentor skill that gives Copilot the full context of what a lecture should contain: topic identification, the brute force to optimal approach structure, complexity analysis requirements, and the YouTube search step. Without Copilot, writing the dsaMentor.js orchestration logic and getting the agent to consistently produce structured markdown output would have taken significantly longer. I then use Copilot cli

Bitcoin can look simple from the outside: paste an address, choose an amount, send. Under that simple interface are several concepts that are useful for developers and technical beginners to understand. This post is not trading advice and does not discuss price. It is a practical mental model for what is happening when someone sends Bitcoin. 1. A wallet does not "hold coins" the way an app balance does Many beginners imagine a wallet as a container full of coins. That is close enough for casual conversation, but it can be misleading. A Bitcoin wallet manages keys and helps create transactions. The Bitcoin network tracks spendable outputs on the ledger. When you send BTC, the wallet constructs a transaction that spends previous outputs and creates new outputs. You do not need to master every detail on day one, but the high-level idea matters: control of keys controls the ability to spend. 2. An address is a destination, not an identity A Bitcoin address is where funds can be sent. It is not a username and it is not automatically tied to a person in the way a social profile is. Before sending, beginners should check the address carefully. A small copy-paste mistake can be permanent. Malware can also replace clipboard contents, so visually checking the beginning and ending characters is a useful habit. For larger transfers, a tiny test transaction can reduce risk. 3. Fees are about block space Bitcoin transactions compete for limited block space. A fee is not a tip to a company. It is part of the transaction economics that helps miners decide which transactions to include. When the network is busy, low-fee transactions may wait longer. When the network is quieter, confirmations may happen faster. The beginner lesson is simple: do not assume "sent" means "fully settled." Check confirmations and understand that fee choice can affect waiting time. 4. The mempool is a waiting area Before a transaction is confirmed in a block, it may sit in the mempool, which is a pool of u

Leetcode 27: Remove Element Leetcode 27 asks us to remove a specific value from an array. The value to be removed is passed in as a parameter to the function along with the array. Just as we did in Day 1, we will cover a naive approach and an optimized approach and discuss the trade-offs between them. I think in the end there's a pretty clear winner. Let's get started. For both approaches we will use the following values: nums = [1, 3, 3, 2, 4] val = 3 Approach 1: Naive (For Loop + Splice) This approach uses a for loop and leverages .splice() for removals. Solution: var removeElement = function ( nums , val ) { let k = 0 ; for ( let i = 0 ; i < nums . length ; i ++ ) { if ( nums [ i ] === val ) { nums . splice ( i , 1 ); i -- ; } else { k ++ ; } } return k ; }; We begin by initializing a variable k to 0. We then enter the for loop. The condition is standard: create a variable i initialized to 0, continue looping while i is less than nums.length to avoid going past the end of the array, and increment by 1 each time through. Each iteration checks one condition: whether nums[i] is equal to val . If true, we call .splice() on the array. The arguments we pass to splice are i and 1 . i is the index at which we want to start removing, and 1 tells splice to remove only that one element. We then decrement i . The reason for this took me some time to wrap my brain around, so I have included a visual below to make it concrete. The core issue is this: when splice removes an element, every element to the right shifts one index to the left. Without i-- , the loop would increment i on the next iteration and skip right over the element that just shifted in. i-- counteracts that by stepping i back, so after the loop increments it, i lands exactly where the shifted element now sits. If nums[i] !== val , we skip the splice and increment k instead. At the end we return k , which holds the count of elements remaining after all occurrences of val have been removed. Time complexity: O(n²)

What can I say. Anyone claiming that F# is good mostly for finance and data processing and C# for everything else, has probably never written a single line of practical F# code. In previous two parts of the article, I tried to demonstrate that with F# you can achieve the same goals as with C#, but with less verbose, repetitive, structural code. How it started. At some point, developers realized that global state with unrestricted data access causes many side effects, producing insecure, error-prone, and hard-to-maintain code as software grows larger. That is when the idea emerged to bring data and the code operating on it together into a single unit, restricting direct access to the unit’s internal state and making software more secure and predictable. This is how data encapsulation was born. Alongside encapsulation, abstraction was introduced — the process of hiding how behavior works. Encapsulation ( hiding data ) and abstraction ( hiding behavior ) remain two foundational pillars of Object-Oriented Programming. And that is how OOP has worked ever since — developers bring data and behavior together ( classes ) and define abstractions for them ( interfaces ). For example, for C# developers — including myself — this has become a daily routine. And we rarely question it, because OOP languages like C# leave us little choice but to structure code this way. But if you ask yourself whether this repetitive routine is always necessary, the answer is — no. You don’t need OOP concepts to build stateless, streamlined request–response, data-processing pipelines, because in such systems there is no long-lived state to hide and protect. You have a request, and almost immediately you have a response. After that, everything is gone. That is what I tried to demonstrate in the first two parts of this article by applying FP concepts. And even if you have a classical desktop application, you don’t always need to approach it in an OOP way. Functional programming handles side effects no

There's been no shortage of debate lately about whether grinding Leetcode still makes sense in the age of AI. I think it does. AI is a powerful tool, but it was built by humans; which means it inherited our strengths, our blind spots, and our biases. Leaning on it entirely without understanding what's happening under the hood is a risk. A mentor once told me: those who refuse to use AI are not hireable. But neither are those who rely on it entirely. Learning deeply is how you stay on the right side of that line. This is my journey into just that - learning deeply. Day 1 Leetcode 88: Merge Sorted Array This is an interesting problem. You begin with 4 pieces of data — 2 arrays and 2 integers: nums1 : a sorted array whose length equals nums1.length + nums2.length . The first m elements are valid numbers; the remaining indexes hold 0 s as placeholders. nums2 : a sorted array containing only valid numbers, with a length of n . m : the count of valid numbers in nums1. n : the count of valid numbers in nums2. The objective is to merge both arrays into sorted order in place . Since nums1 is already sized to hold every valid element from both arrays, it's where the final sorted result will live. Approach 1: Naive (Splice + Sort) This solution is 2 lines of code. That's it. It's a testament to how much ES6 advanced JavaScript. nums1 . splice ( m , n , ... nums2 ); nums1 . sort (( a , b ) => a - b ); Here's how it works. We start by calling .splice() on nums1. While .splice() has many use cases, here's what each argument is doing in this context: m : the index where we start deleting elements. Since m is the count of valid numbers in nums1, starting at index m puts us right at the first placeholder 0 — exactly where we want to be. n : the number of elements to delete. Since n equals the length of nums2, we're deleting exactly as many placeholders as we have values to insert. ...nums2 : the values we want to insert in place of the deleted elements. The ... is the spread operato

🏦 Day 6 of 7: Building a Mini Uniswap in 80 Lines of Solidity Imagine a vending machine. It has 1,000 coffee beans and 1,000 coins. No menu, no cashier — just one iron rule: the product of the two numbers inside must never decrease. That's it! This is how Uniswap works — and this is what I built on Day 6, coming from .NET. Here's how, why it's elegant, and where you can step on a rake. Why an Order Book Doesn't Work on a Blockchain Traditional exchanges — Binance, NYSE, any CEX — run on an order book . Market makers post bids and asks. A matching engine pairs them. Millions of updates per second, all in a centralised database. In a blockchain, this is impossible. Transactions take 12 seconds. Every state change costs gas. Storing millions of constantly changing orders would eat all the profit before a single trade completes. Uniswap's solution: replace the order book with a liquidity pool — a smart contract holding two tokens — and replace the matching engine with pure math. Just a formula — below. x · y = k — The Formula That Broke Finance The Constant Product Invariant : x · y = k Where x is the reserve of Token0, y is the reserve of Token1, and k is a constant that must never decrease during swaps. When a trader sells Token0 into the pool, x increases. To keep k constant, y must decrease — the contract sends out Token1. The price is determined automatically by the ratio of reserves. Live example with numbers: Pool: 1,000 Token0, 1,000 Token1. k = 1,000,000. Trader sells 100 Token0: amountOut = (reserveOut × amountIn) / (reserveIn + amountIn) amountOut = (1000 × 100) / (1000 + 100) amountOut = 100,000 / 1,100 amountOut ≈ 90.9 Token1 The trader gets ~90.9, not 100. That gap is slippage — and it's not a bug. It's the formula protecting the pool. The more you buy relative to pool size, the worse your price gets. Naturally. Mathematically. After the swap: pool has 1,100 Token0 and ~909.1 Token1. k ≈ 1,000,000. Invariant holds. The Contract: SimpleAMM Three functions.