Interview Prep
Most interview lists give you a question and a one-line answer that falls apart the moment someone asks "why". These sets explain the reasoning, so you can handle the follow-up instead of memorising a script.
By language
- Design Patterns: The Five You Will Actually Meet Design patterns are names for solutions people kept reinventing. Learning them as a catalogue to apply is how codebases get worse; learning them as names for things you already do is how they help. Tutorial · 10 min read · August 20, 2026
- How Java Actually Runs: The JVM, Bytecode and Two Surprising == Results Java's promise was write once, run anywhere, and the JVM is how that works. Two of its optimisations also produce the most confusing == results a beginner will meet. Tutorial · 9 min read · August 19, 2026
- Java Exception Handling: Checked, Unchecked, and What Not to Do Java is one of the few languages that forces you to deal with certain exceptions. That design is debated, but the practical consequence is a set of habits worth getting right early. Tutorial · 9 min read · August 19, 2026
- OOP in Python Explained with Code You Can Actually Run Object-oriented programming is usually taught with cars and animals that never appear in real code. Here it is with programs you can paste into a file and run, including the one mistake that bites almost every beginner. Tutorial · 11 min read · August 15, 2026
- Modern JavaScript Features You Should Actually Be Using Modern JavaScript is mostly a set of shortcuts that make ordinary code shorter and safer. A few of them also fix genuine bugs that older syntax made easy to write. Tutorial · 9 min read · August 14, 2026
- String Problems That Keep Coming Up in Interviews Most string interview questions are four patterns wearing different clothes. Learn the patterns and the individual problems stop needing to be memorised. Tutorial · 9 min read · August 11, 2026
- Linked Lists in Python: Building One and Understanding Why Python has lists built in, so why build a linked list? Because the interview asks, and because the reversal problem teaches a pointer technique you will meet again and again. Tutorial · 9 min read · August 11, 2026
- Binary Search Trees: Fast Lookup Until Your Data Arrives Sorted A binary search tree gives you logarithmic lookup from one simple rule. The same rule is why inserting already-sorted data destroys its performance entirely. Tutorial · 9 min read · August 10, 2026
- Dijkstra's Algorithm: Shortest Paths, Step by Step Dijkstra answers the question every maps application asks: what is the cheapest route from here to everywhere? The algorithm is short, and the reason it fails on negative weights is worth understanding. Tutorial · 9 min read · August 10, 2026
- Greedy Algorithms: When Taking the Best Option Now Actually Works A greedy algorithm takes the best-looking option at every step and never reconsiders. Sometimes that is provably optimal. Sometimes it is confidently wrong, and the same code cannot tell the difference. Tutorial · 9 min read · August 10, 2026
- Bit Manipulation: The Tricks That Keep Appearing in Interviews Bit manipulation looks like a party trick until you meet the problems it solves in one line. A handful of patterns cover almost everything that gets asked. Tutorial · 8 min read · August 10, 2026
- Tries: How Autocomplete Finds Every Word Starting With 'ca' A hash set can tell you whether a word exists. It cannot tell you which words start with 'ca' without checking all of them. That gap is what a trie fills. Tutorial · 8 min read · August 10, 2026
- Union-Find: Answering 'Are These Two Connected?' Almost Instantly Union-find does two things: merge two groups, and check whether two items are in the same group. With two small optimisations, both become effectively constant time. Tutorial · 8 min read · August 10, 2026
- Topological Sort: Ordering Things That Depend on Each Other Course prerequisites, build systems and task schedulers all ask the same question: given what depends on what, in what order should these run? Topological sort answers it, and tells you when no answer exists. Tutorial · 8 min read · August 10, 2026
- Recursion in Python: How to Stop Being Confused by It Recursion stops being confusing the moment you stop trying to trace it in your head. Trust the base case, trust the smaller call, and the rest follows. Tutorial · 9 min read · August 10, 2026
- Java Threads: The Race Conditions You Cannot See count++ is three machine operations, not one. That single fact explains lost updates, why volatile does not fix them, and why the bug never reproduces on your laptop. Tutorial · 13 min read · August 6, 2026
- Java Generics: Type Erasure and What It Breaks A list declared to hold Strings can genuinely contain an Integer, and the ClassCastException fires nowhere near the line that put it there. Erasure explains why. Tutorial · 13 min read · August 6, 2026
- JavaScript Prototypes Explained: The Chain Behind class Only functions have a prototype property. Objects have a hidden link called __proto__. Confusing the two costs most beginners an hour, and costs candidates the interview. Tutorial · 11 min read · August 6, 2026
- JavaScript Interview Questions for Freshers (With Answers) The list is shorter than you think. Interviewers reuse about fifteen questions, and they are checking whether you understand the mechanism or memorised a definition. Career · 12 min read · August 6, 2026
- Python Interview Questions for Freshers (With Answers) Interviewers probe the same handful of Python topics. Knowing why mutable defaults break is worth more than listing twenty built-in functions. Career · 12 min read · August 6, 2026
- React Interview Questions and Answers for Beginners React interviews test whether you understand rendering, not whether you can list hooks. The state-batching question catches most candidates. Career · 12 min read · August 6, 2026
- OOP Interview Questions and Answers (Java, Python, C++) Every placement asks about the four pillars. The answers that stand out give a reason for each concept rather than a textbook definition. Career · 12 min read · August 6, 2026
- Java NullPointerException: Causes and How to Prevent It Called a billion-dollar mistake by the man who invented null. Reading the newer error messages properly turns most of these into thirty-second fixes. Tutorial · 10 min read · August 6, 2026
- The JavaScript this Keyword, Finally Explained this is not decided by where a function is written. It is decided by how the function is called — which is why the same function behaves differently in two places. Tutorial · 10 min read · August 5, 2026
- JavaScript Hoisting Explained: var, let, const and Functions Nothing is physically moved to the top of the file. Understanding what actually happens explains why var returns undefined while let throws. Tutorial · 9 min read · August 5, 2026
- The JavaScript Event Loop Explained With Examples JavaScript runs on one thread and still handles thousands of things at once. The event loop is how — and it explains every async ordering puzzle you have hit. Tutorial · 10 min read · August 5, 2026
- OOP Concepts in Java Explained with Examples The four pillars of OOP in Java, made simple. See encapsulation, inheritance, polymorphism and abstraction with tiny code examples and interview notes. Tutorial · 9 min read · July 22, 2026
Computer-science fundamentals
- TCP/IP Explained: What Happens When You Open a Website "What happens when you type a URL and press enter" is asked in interviews because a good answer touches every layer of the stack. Here is that journey, in order. Tutorial · 9 min read · August 18, 2026
- Deadlock: Why Two Threads Can Wait Forever A deadlocked program does not crash. It sits there, using no CPU, responding to nothing, looking almost like it is working — which is why it is one of the more unpleasant bugs to meet in production. Tutorial · 8 min read · August 17, 2026
- Process vs Thread: The Difference, and Why It Matters The textbook answer is that a process is a program in execution and a thread is a lightweight process. That is true and useless. The real difference is what they share, and it explains everything else. Tutorial · 8 min read · August 16, 2026
- SQL Views and Triggers: Saved Queries and Automatic Reactions A view is a saved query that always reflects current data. A trigger runs code automatically when data changes — which is powerful, and the reason some bugs are impossible to find by reading the application. Tutorial · 8 min read · August 12, 2026
- Stored Procedures: Logic That Lives in the Database A stored procedure is a named block of SQL saved in the database and called by name. It is genuinely useful for a narrow set of problems and widely regretted outside them. Tutorial · 8 min read · August 12, 2026
- ACID Properties: What a Database Transaction Actually Guarantees ACID is four words everyone memorises for exams. Each one exists because of a specific disaster, and the disasters are far easier to remember than the definitions. Tutorial · 9 min read · August 12, 2026
- Database Indexing: Why One Query Takes Milliseconds and Another Takes Minutes An index is the difference between checking every row and going straight to the right one. It is also the most common reason a query that was fast in development crawls in production. Tutorial · 9 min read · August 11, 2026
- Database Normalization Explained Without the Textbook Definitions Normal forms are usually taught as definitions to memorise. They are much easier to understand as answers to one question: what goes wrong if the same fact is stored twice? Tutorial · 10 min read · August 10, 2026
- Computer Networks Interview Questions With Real Answers Everyone can recite the seven OSI layers. The interview is decided by the follow-up question, which is usually about where a device or a protocol actually sits. Career · 12 min read · August 6, 2026
- The OSI Model Explained With One Real Request Layers 5 and 6 have no separate implementation on any machine you own. Here is what the model is actually for, and what it tells you when something breaks. Tutorial · 11 min read · August 6, 2026
- How to Approach a Coding Round Without Freezing Most candidates fail coding rounds by process, not knowledge. Silence while thinking costs more marks than an imperfect solution. Career · 11 min read · August 6, 2026
- DBMS Interview Questions and Answers for Freshers DBMS theory rounds are predictable. Normalisation, ACID and keys account for most of what campus interviews ask. Career · 12 min read · August 6, 2026
- Operating System Interview Questions and Answers OS rounds reuse about a dozen questions. Process versus thread and the four deadlock conditions are near-guaranteed. Career · 12 min read · August 6, 2026
- DSA Patterns Cheat Sheet: Recognise the Problem Type Interview problems reuse about a dozen patterns. Recognising which one applies is most of the solution — the code is the easy part. Tips & Tricks · 11 min read · August 6, 2026
- Binary Tree Traversal: Inorder, Preorder and Postorder Three traversals differ by one line's position. Knowing which one a problem needs is usually the whole solution. Tutorial · 10 min read · August 6, 2026
- Dynamic Programming Explained for Beginners DP has a reputation for being hard. It is really one idea — do not solve the same subproblem twice — applied with discipline. Tutorial · 12 min read · August 6, 2026
- Recursion vs Iteration: Which to Use and Why Anything one can do, the other can too. The choice is about which makes the problem clearer — and which one the stack can survive. Comparison · 9 min read · August 6, 2026
- Heaps and Priority Queues Explained With Examples A heap gives you the smallest or largest item instantly without keeping everything sorted. That trade is why top-K questions have such a clean solution. Tutorial · 10 min read · August 6, 2026
- Backtracking Explained: The Template That Solves Most Problems Backtracking is brute force that gives up early. One template — choose, explore, undo — covers subsets, permutations, sudoku and N-queens. Tutorial · 11 min read · August 6, 2026
- Time Complexity Cheat Sheet for Interviews Every complexity you need for an interview, in one place — plus the table that tells you which complexity a problem's constraints are asking for. Tips & Tricks · 10 min read · August 6, 2026
- LeetCode vs HackerRank vs CodeChef: Which to Practise On They are built for different goals. Using the wrong one is why months of practice sometimes produces no interview improvement. Comparison · 9 min read · August 5, 2026
- The Two Pointer Technique Explained With Examples One of the highest-return patterns in interviews. It turns a nested loop into a single pass — but only when the data has the property that makes it safe. Tutorial · 9 min read · August 5, 2026
- Sliding Window Technique: Fixed and Variable Windows Any question about a contiguous subarray or substring is probably a sliding window. The trick is knowing what makes the window shrink. Tutorial · 10 min read · August 5, 2026
- BFS vs DFS: Which Graph Traversal to Use The code for both is nearly identical — swap a queue for a stack. That one change decides whether you find the shortest path or merely a path. Comparison · 10 min read · August 5, 2026
- Time Complexity and Big O Notation Explained Simply Big O is not about how many seconds your code takes. It is about how the work grows as the input grows — and that difference is what interviewers are actually testing. Tutorial · 10 min read · August 5, 2026
- Array vs Linked List: Which One and Why Textbooks say linked lists are better for insertion. Real machines often disagree, and knowing why is what separates a memorised answer from an understood one. Comparison · 9 min read · August 5, 2026
- Stack vs Queue: The Difference, With Real Examples One reverses order, the other preserves it. That single difference decides whether you get undo, or you get a printer queue. Comparison · 8 min read · August 5, 2026
- Hash Tables Explained: How Dictionaries Really Work Every dictionary, map and object you have ever used is a hash table. Understanding the machinery explains a surprising amount of everyday behaviour. Tutorial · 10 min read · August 5, 2026
- Sorting Algorithms Compared: Which to Use and Why You will almost never write a sort in production. You will absolutely be asked to explain one in an interview, and the trade-offs are the actual lesson. Comparison · 11 min read · August 5, 2026
- How to Prepare for a Technical Interview: A Step-by-Step Guide A practical, step-by-step plan for freshers: what technical interviews test, a 4-week timeline, live-coding etiquette, and how to handle questions you can't solve. Career · 8 min read · July 22, 2026
- What Is Recursion? Explained Simply with Examples Recursion is when a function calls itself. Here is how the base case, recursive case, and call stack work, with clear Python examples for beginners. Tutorial · 9 min read · July 22, 2026
More on Interview Prep
- The STAR Method for Behavioral Interviews Most people know the acronym and still ramble through the answer. The method only works if you spend your time on the last two letters, not the first two. Career · 7 min read · September 8, 2026
- How to Explain an Employment Gap in an Interview Interviewers aren't scoring your gap on a morality scale. They're checking one specific thing, and a short honest answer clears it faster than a long one. Career · 7 min read · September 7, 2026
- The CAP Theorem: The Choice You Make During a Network Failure CAP is usually taught as picking two of three, which is not quite what it says. The real statement is narrower and more useful: when the network fails, you must choose between being correct and being available. Tutorial · 9 min read · August 22, 2026
- Sharding: Splitting a Database That Outgrew One Machine Sharding splits your data across several databases so no single machine holds it all. It also makes joins, transactions and unique constraints much harder, which is why it should be a late decision. Tutorial · 9 min read · August 22, 2026
- Microservices vs Monolith: Why Most Projects Should Start Boring Microservices are presented as the modern way to build software and a monolith as what you migrate away from. The real trade is that microservices convert a code problem into a distributed-systems problem. Comparison · 9 min read · August 22, 2026
- Caching: Making Things Fast, and the Two Hard Problems Caching is the easiest large performance win available and the source of some of the most confusing bugs in software. Both facts come from the same place: a cache is a second copy of the truth. Tutorial · 9 min read · August 21, 2026
- SOLID Principles Explained With Code That Is Actually Bad First SOLID is usually taught as five definitions to memorise, which is why people can recite it and not apply it. Each principle is much clearer when you first see the code it exists to prevent. Tutorial · 10 min read · August 20, 2026
- Remote Jobs for Freshers: Honest Odds and How to Improve Them Remote work is more available than ever and less available to freshers than to anyone else. Understanding why makes it clear what would change a company's mind. Career · 8 min read · August 19, 2026
- Hashing vs Encryption vs Encoding: Three Things People Confuse Base64 is not encryption. A hash is not reversible. Encrypting a password is a mistake. These three confusions cause a large share of real security failures. Tutorial · 9 min read · August 18, 2026
- How to Explain Your Project in an Interview Without Rambling "Tell me about your project" is the question freshers are most sure they will pass and most often fail. The problem is never the project. It is that a feature tour answers a question nobody asked. Career · 10 min read · August 17, 2026
- Message Queues: Why Your Signup Should Not Wait for the Email A signup that takes four seconds because it is waiting for a confirmation email is doing work in the wrong place. Queues are how that work moves out of the request, and they bring their own rules. Tutorial · 9 min read · August 15, 2026
- SQL CTEs: Turning an Unreadable Query Into Readable Steps A query with three levels of nested subqueries is read from the inside out, which is why nobody wants to touch it. A CTE lets you write the same logic as named steps read top to bottom. Tutorial · 8 min read · August 13, 2026
- OAuth Explained: What 'Sign in with Google' Is Actually Doing OAuth exists to answer one question: how do you let an app act on your behalf without handing it your password? The answer is a redirect dance that looks confusing and is genuinely elegant. Tutorial · 9 min read · August 13, 2026
- Webhooks: Getting Told Instead of Asking Repeatedly Polling an API every ten seconds to ask whether a payment succeeded is wasteful and slow. A webhook reverses it: the other service calls you the moment something happens. Tutorial · 8 min read · August 13, 2026
- Rate Limiting: Stopping One Client Taking Down Your API Without a rate limit, one buggy client in a retry loop can consume everything your API has. The algorithms are simple; choosing the right one depends on whether bursts are acceptable. Tutorial · 8 min read · August 13, 2026
- SQL Window Functions: Aggregates Without Losing Your Rows GROUP BY answers 'what is the total per region' by throwing away the individual rows. Window functions answer it while keeping every row, which is what you usually actually wanted. Tutorial · 9 min read · August 12, 2026
- Load Balancers: How One Address Serves Many Servers The moment one server is not enough, you need something in front deciding where each request goes. That decision is simple until you remember the server was storing things in memory. Tutorial · 9 min read · August 12, 2026
- Group Discussion Rounds: How to Be Selected Without Shouting Group discussions reward the person who moves the conversation forward, not the person who talks most. That is good news if you are quiet, and a warning if you are not. Career · 8 min read · August 11, 2026
- Off-Campus vs On-Campus Placement: How to Approach Both On-campus is convenient but limited by which companies visit your college. Off-campus is harder and has no ceiling — and most people should do both. Career · 11 min read · August 6, 2026
- How to Write an ATS-Friendly Resume as a Fresher Your resume is probably parsed by software before a human sees it. Most fresher resumes fail on formatting rather than content. Career · 10 min read · August 6, 2026
- How to Get Job Referrals (Even If You Know Nobody) A referral moves your application from a pile of thousands to a recruiter's screen. Most students never ask, and most who do ask badly. Career · 10 min read · August 6, 2026
- SQL Commands Cheat Sheet for Interviews and Daily Work Every SQL command you need in one place, with the execution order that explains most of the errors beginners hit. Tips & Tricks · 10 min read · August 6, 2026
- SQL Interview Questions for Freshers (With Answers) SQL rounds are predictable. Joins, aggregation and one query about the second-highest salary account for most of what you will be asked. Career · 12 min read · August 6, 2026
- Service-Based vs Product-Based Companies: Which to Join The advice online is heavily one-sided. The honest version is that both are reasonable starts, and the wrong choice is the one made out of fear. Career · 10 min read · August 5, 2026
- HR Interview Questions and Answers for Freshers (With Examples) The HR round trips up many freshers. Here are honest, ready-to-use answers to the most common HR interview questions, tuned for Indian freshers. Career · 8 min read · July 22, 2026
- How to Get a Coding Internship With No Experience A practical, honest guide for beginners and freshers: what to build, where to apply, how to cold email, and which internship offers to walk away from. Career · 8 min read · July 22, 2026
- Beating Imposter Syndrome as a Junior Developer Imposter syndrome hits new and self-taught coders hardest. Here are honest, practical ways to quiet the self-doubt and keep shipping code with confidence. Career · 8 min read · July 22, 2026
- How to Switch to a Tech Career From a Non-CS Background You don't need a CS degree to work in tech. An honest roadmap for non-CS grads: the first role to target, a realistic timeline, and how to prove your skills. Career · 8 min read · July 22, 2026
- System Design Basics for Beginners (Explained Simply) A beginner-friendly walk through system design using one example — a URL shortener — covering clients, servers, databases, caching, and scaling. Career · 8 min read · July 22, 2026
- How to Negotiate Your First Salary as a Fresher Developer A practical, honest guide for Indian freshers: when salary negotiation is realistic, how to research pay, counter an offer politely, and read CTC vs in-hand. Career · 8 min read · July 22, 2026
- How to Write a Software Engineer Resume for Freshers A practical, section-by-section guide to writing a strong software engineer resume when you have no work experience yet — built for Indian freshers. Career · 8 min read · July 22, 2026
- How to Land Your First Developer Job in India What actually gets a fresher hired: the projects that count, how to apply off-campus, and what interviewers look for when you have no experience yet. Career · 12 min read · May 7, 2026