标签：#interview

A Go interview is rarely about syntax alone. Yes, you should know how slices work, how goroutines...

Java LLD: Designing Snakes and Ladders with O(1) Move Resolution Designing Snakes and Ladders is a classic LLD (Low-Level Design) interview question that tests your ability to write clean, maintainable, and highly performant code. While the rules are simple, naive implementations quickly fall apart under scale, concurrency, or changing business requirements. Want to go deeper? javalld.com — machine coding interview problems with working Java code and full execution traces. The Mistake Most Candidates Make Expensive Runtime Scans : Iterating through lists of snakes and ladders on every single move, turning an $O(1)$ lookup into a slow $O(N)$ search. Violating SRP : Hardcoding board mechanics, game loops, and dice rolling logic inside a single monolithic class. Tight Coupling : Binding player movement directly to the dice, making it incredibly difficult to introduce custom game rules (e.g., crooked dice or extra turns). The Right Approach Core mental model : Treat the board as a flat, pre-computed $O(1)$ lookup array where each index represents a cell and its value represents the final destination. Key entities/classes : Board , Jump (representing Snakes/Ladders), Player , Dice , Game , and MovementStrategy . Why it beats the naive approach : It decouples board setup from game loop execution, turning expensive runtime lookups into instantaneous array access. The Key Insight (Code) public class Board { private final int [] board ; // Pre-computed jump destinations public Board ( int size , List < Jump > jumps ) { this . board = IntStream . range ( 0 , size + 1 ). toArray (); jumps . forEach ( j -> board [ j . start ()] = j . end ()); // Precompute O(1) lookups } public int resolvePosition ( int current , int roll ) { int next = current + roll ; return next < board . length ? board [ next ] : current ; } } Key Takeaways DP-Style Precomputation : Pre-populating a lookup array transforms runtime search complexity from $O(N)$ to $O(1)$ time complexity per turn. Open-Closed

When designing systems like Facebook, WhatsApp, Netflix, Amazon, or Instagram, one of the first questions a system designer asks is: Can a single server handle the traffic? How much storage will be needed? Do we need caching? How much RAM should our cache have? How many servers should we deploy? Before discussing databases, load balancers, microservices, or caching layers, we need a rough understanding of the scale. This is where Back-of-the-Envelope Calculations come into the picture. Why Do We Need Back-of-the-Envelope Calculations? Imagine you're asked to design Facebook. If you immediately start drawing: Load Balancer ↓ Application Servers ↓ Redis Cache ↓ Database without knowing the expected traffic, you're designing blindly. System design is fundamentally about making trade-offs. To make those trade-offs, we first need estimates. Back-of-the-envelope calculations help us answer: How much traffic will the system receive? How much data will be generated? How much cache memory is required? How many servers are needed? The numbers don't need to be perfect. They only need to be close enough to make architectural decisions. What Exactly Is a Back-of-the-Envelope Calculation? A quick estimation technique used to approximate: Traffic Storage Memory Server Capacity using rough assumptions. Think of it as: "Getting the order of magnitude correct rather than getting the exact number correct." A system designer rarely needs perfect accuracy during interviews. They need reasonable estimates. The Standard Estimation Flow Whenever you get a System Design question: Users ↓ Traffic ↓ Storage ↓ RAM / Cache ↓ Number of Servers ↓ Architecture Design Always estimate first. Design later. The Ultimate Estimation Cheat Sheet Storage Units Unit Value 1 KB 10³ Bytes 1 MB 10⁶ Bytes 1 GB 10⁹ Bytes 1 TB 10¹² Bytes 1 PB 10¹⁵ Bytes Time Units Unit Value 1 Minute 60 Seconds 1 Hour 3600 Seconds 1 Day 86,400 Seconds Common Assumptions Metric Approximation Peak Traffic 3× Average Traffic Active

I got a take-home assignment last year from a company I was genuinely excited about. "Should take about four hours," the recruiter said. Build an ingestion pipeline, model the data, write tests, document your design decisions, and prepare a 15-minute presentation walkthrough for the panel. Four hours. I laughed, closed my laptop, and started on it the next morning like it was a sprint. Sixteen hours later I had something I was proud of. Clean pipeline, solid tests, real documentation. I submitted it on a Sunday night. Monday I got a form rejection. No notes. No feedback. Not even which stage I failed. Just "we've decided to move forward with other candidates" and a link to their Glassdoor page. That was the moment I stopped pretending take-homes are assessments. They're consulting gigs. Unpaid ones. The Scope Creep Nobody Talks About Five years ago, a data engineering take-home was a focused exercise. Model this dataset into a star schema. Write a few SQL transforms. Maybe a short README. Two to four hours, tops. Bounded, reasonable, and actually useful for evaluating how someone thinks about data. That version is dead. Today, 68% of companies use take-home tests, up 12% year over year. And the scope has quietly ballooned into something unrecognizable. Full pipeline implementations. Test suites with coverage thresholds. Documentation that reads like a design doc. A presentation follow-up where you defend your architecture to a panel. We're talking 10 to 20 hours of work, routinely, for a role you haven't been offered. Industry best practice caps take-homes at 90 minutes of expected effort. The reality? Candidates consistently take 2x longer than company estimates to reach submission quality. That "four-hour" assignment is an eight-hour assignment. That "weekend project" is a week of evenings. And 25% of companies are still handing these out like they're reasonable asks. Here's the part that makes my eye twitch: 71% of engineering leaders openly say take-homes no lon

President Trump probably can’t get rid of her yet, but FCC commissioner Anna Gomez still checks her email every day to see if he has. Until then, she wants to stand up for the First Amendment.

I bombed a system design interview last year — not because I didn't know the architecture, but because I spent the first 5 minutes fighting Excalidraw. So I built SystemDesignBoard — a free, keyboard-first whiteboard specifically for system design interviews. What it does You open it, press a key, and start drawing. No account, no onboarding, no drag-from-a-sidebar friction. R → place a Service node C → place a Database/Cache/Queue A → connect two nodes N → open the scratchpad for scale math The features I'm most proud of Animated connectors that show communication type Instead of just drawing arrows, connectors visually encode how services talk: ⇄ sync — paired dashes (request + ACK) ≋ stream — near-solid fast line with glow (continuous pipeline) This matters in interviews — your interviewer can glance at your diagram and immediately understand the communication pattern. Cloud provider badges Tag any node as AWS (EC2, Lambda, RDS, S3), GCP (GKE, Cloud Run, Firestore), or Azure. Each subtype has its own icon. Trade-off logging Right-click any node → Log Trade-offs → attach your CAP theorem stance, consistency level, and scaling strategy directly to the component. Diagram-as-Code Type: [Mobile App] -> [API Gateway] [API Gateway] -> [Auth Service] [Auth Service] -> [Users DB] [Feed Service] -> [Posts DB x3] [Feed Service] -> [Redis Cache] Hit Apply — it auto-lays out the whole architecture in seconds. Export to animated GIF Export your diagram as a GIF that shows live traffic flow animations. Great for sharing after an interview or in a design doc. Tech stack React + TypeScript + Vite @xyflow/react (ReactFlow v12) for the canvas Zustand + Immer for state with full undo/redo html-to-image + gifshot for PNG/GIF export It's free and open No signup required. Works entirely in the browser. Free during beta. 👉 systemdesignboard.com Would love feedback — especially from anyone who's done system design interviews recently. What's missing? What's annoying? Drop a comment below

Stefan Paul Goetsch, better known as Hainbach, is a German experimental composer, artist, and YouTuber who is perhaps most famous for making music with laboratory equipment and scientific instruments. He describes it as being like the "Dark Souls of synthesis." Despite using "hard mode" production techniques that often rely on telephone line testing equipment and […]

When Colin Farrell was doing press for the first season of the detective series Sugar, he had to be very careful with how he spoke. Sugar is a story about a quirky private detective, but it's also secretly a work of science fiction, something that doesn't become clear until halfway through the season. "I knew […]

One of the most common system design interview questions is: "How would you scale a web application from 100 users to 100 million users?" The answer is rarely a single technology. Instead, systems evolve through multiple stages, with each stage solving a specific bottleneck. This article walks through the typical evolution of a scalable system and explains why , how , and when each component is introduced. 1. Single Server Why Start Here? Every application starts simple. In the beginning: Traffic is low Development speed matters more than scalability Infrastructure costs should be minimal What Is It? A single machine handles everything: Frontend Backend Database Users | v Single Server ├── Application └── Database How Does It Work? User sends request. Application processes request. Database stores and retrieves data. Response is returned. Everything happens on one machine. Problem As traffic grows: CPU becomes overloaded Memory becomes insufficient Database competes with application for resources A single server becomes a bottleneck. Interview One-Liner A single server architecture is simple and cost-effective but becomes a bottleneck as traffic and resource usage increase. 2. Application and Database Separation Why Do We Need It? The application and database have different workloads. Application Server: Uses CPU Handles business logic Database Server: Uses memory and storage Handles queries Keeping them together causes resource contention. How Does It Work? Move the database to a separate machine. Users | v Application Server | v Database Server Benefits Independent scaling Better resource utilization Improved performance Example Suppose an e-commerce website receives thousands of requests. The application handles: Authentication Order processing API responses The database handles: Product data Orders User information Separating them prevents one workload from affecting the other. Interview One-Liner Separating the application and database allows each layer to scal

Infowars’ would-be creative director talks Sandy Hook, comedy’s MAGA turn, and why the future of satire may look more like a streaming startup than a late-night show.

I use a form validation problem as a technical interview question. It's deceptively simple — and the solutions people reach for reveal a lot about how they think. Then I tried it on Claude, ChatGPT, and Gemini. The results were illuminating, but not for the reasons I expected. The Problem Many form libraries share a common convention: form data is represented as a plain nested object, and the validation function returns an object of the same shape containing the errors. You'll find this pattern in Formik and React Final Form in React, and — full disclosure — in Inglorious Web , my own framework, which ships form handling built in without any extra dependencies. const values = { productName : ' VR Visor ' , quantity : 1 , homeAddress : { street : ' Long St ' , zip : ' 00666 ' }, shippingAddress : { street : ' Short St ' , zip : ' 00777 ' , co : ' Inglorious Coderz ' }, billingAddress : { street : ' Wide Plaza ' , zip : ' 00888 ' , vat : ' 1142042 ' }, } The validation function should return an object containing all errors found. A starting example: function validate ( values ) { const errors = {} if ( ! values . productName ) { errors . productName = ' required ' } return errors } The ask: extend this to validate every field . Notice that the three address types aren't identical. shippingAddress requires a co field. billingAddress requires a vat . These differences matter — and how you handle them reveals a lot. Four Solutions, Four Instincts 1. The Flag — the average human The most common approach I see in interviews is a single validateAddress function with a type parameter: function validateAddress ( values = {}, type ) { const errors = {} if ( ! values . street ) errors . street = ' required ' if ( ! values . zip ) errors . zip = ' required ' if ( type === ' shipping ' && ! values . co ) errors . co = ' required ' if ( type === ' billing ' && ! values . vat ) errors . vat = ' required ' return errors } It works. But every new address type, every new special rule,

At 21, Speed has pushed the limits of streaming by transforming a distinctly solo format into a global group chat. His song for this year’s World Cup is becoming the tournament’s unofficial anthem.

Mike Rugnetta is a writer, podcast host, producer, audio engineer, educator, musician, sound designer, and father. In short, the man wears a lot of hats. He's the cocreator and host of the award-winning Never Post, an absolutely must-listen podcast about the internet, as well as Fun City, a TTRPG podcast where he's the GM. He's […]

A few months ago, while interviewing for a Cloud Solutions Architect role at Microsoft, one of the interviewers asked me a question that stuck with me long after the interview ended. Not because I couldn't answer it. But because I kept thinking about whether I had answered it well. The question was: "What's the hardest part about working on mainframe technology?" At the time, I was still relatively new to the world of mainframes. And by "relatively new," I mean embarrassingly new. Before joining my current company, I didn't even know something called a "mainframe" still existed. If you'd asked me what COBOL was, I probably would've guessed it was a Pokémon. Okay that is an exaggeration but you get what I mean. I still remember early on hearing terms like KT (Knowledge Transfer) being thrown around and quietly wondering if everyone had received some secret corporate dictionary except me. The good news is that I've never been particularly afraid of looking stupid. So my strategy is simple: Ask the question. Then ask the follow-up question. Then ask the question that reveals I didn't understand the previous answer either. Surprisingly, people were usually happy to explain. Anyway, after a few KT sessions and what I'd generously describe as a "bare minimum amount of research," my brain went where most developers' brains probably would've gone. The technology The age The tooling The learning curve The fact that some of these systems were designed before I was even born All perfectly reasonable answers. But while I was sitting there in the interview, another thought appeared: "This feels too obvious." Interviewers at that level usually aren't asking for the first answer that comes to mind. They're trying to understand how you think. And the more I reflected on that question afterwards, the more I realized something interesting. The hardest part isn't the technology itself. Before I started working around large enterprise systems, my mental model of old technology was pret

Websites are so back! Today's website worth visiting is The Pelley Minutes, a clever project that puts the career of longtime 60 Minutes correspondent Scott Pelley into perspective. The show may only be 60 minutes long, but Pelley racked up nearly 37,000 minutes in his 37-year long career, reporting on almost everything humanity has put […]

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

In 2019, Alex Vindman testified during President Trump’s first impeachment trial–a decision that ended his military career. Now he wants to challenge the president from the halls of Congress.

Benn Jordan may have initially gained notoriety for his music as Flashbulb and later, reviewing synths and effects pedals on YouTube under Benn and Gear. But about five years ago, Benn decided to take his YouTube channel in a different direction. He didn't stop covering music gear overnight, but as time progressed, his channel became […]

[While preparing for interviews, I realized I had a strange habit. I would solve a problem, get stuck, open the solution, understand it, and move on feeling productive. A few days later, I couldn’t solve a similar problem on my own. The issue wasn’t lack of practice. The issue was that I was consuming solutions faster than I was developing problem-solving skills. So I changed my approach. Instead of looking for answers, I started forcing myself to think longer, write down my ideas, identify where I was stuck, and only then seek guidance. That worked much better. But I couldn’t find a tool that supported this style of learning. Most platforms either: Give you the answer. Give you the editorial. Give you AI that writes the code for you. So I started building my own. The goal was simple: An AI coach that guides the thought process instead of generating the solution. Over time I added: DSA practice System Design preparation Low-Level Design preparation Company-wise interview questions Topic-wise strength and weakness analysis Personalized revision lists The interesting part wasn’t building it. The interesting part was realizing that interview preparation is less about collecting solutions and more about training how you think. What has helped you improve more during interview prep? Reading solutions? Or struggling with the problem first? Sde vault - https://sdevaultweb.onrender.com/

Back in 2015, the two-person studio Metanet released N++, a brutally hard 2D platformer that was a decade in the making, building off of previous releases dating back to the freeware Flash title N. At the time, cofounder Raigan Burns issued some famous last words: "We hope it's not another 10 years before we come […]