Course tips and study guides
Study plans, exam and interview preparation, projects and placements, from people a year or two ahead and the UniCircle team. Every tip names its author and is checked by an editor before it appears.
Topics#javascript#html#java#sql#react#accessibility#dsa#interview#nodejs#arrays#error handling#forms#oop#placements#postgresql#abstract classes#acid#aggregates
23 tips
- GuideEngineeringUndergraduateTwo pointers and sliding window: two patterns that solve dozens of array problemsHow to recognise two-pointer and sliding-window problems, with three tested solutions that turn O(n²) brute force into O(n).#dsa#two pointers#sliding window#arraysUniCircle team2 min
- GuideEngineeringUndergraduateInterface or abstract class in Java? A clear way to decideWhat each one can hold, how default methods changed the picture, and a short example that answers the classic OOP viva question with code.#java#oop#interfaces#abstract classesUniCircle team2 min
- GuideEngineeringUndergraduateJava exceptions: checked versus unchecked, finally and try-with-resourcesHow Java's exception types differ, the exact order in which try, catch and finally run, and why try-with-resources is the right way to close files and connections.#java#exceptions#try-with-resources#error handlingUniCircle team2 min
- GuideEngineeringUndergraduateJava collections: which one to use, and whenA practical guide to choosing between ArrayList, LinkedHashSet, HashMap, TreeMap, ArrayDeque and PriorityQueue, with the time costs interviewers expect you to know.#java#collections#hashmap#data structuresUniCircle team2 min
- GuideEngineeringUndergraduateReact useEffect: when it runs and how to clean upWhat the dependency array really controls, why effects run twice in development, how to clean up timers and subscriptions, and when you do not need an effect at all.#react#useeffect#hooks#cleanupUniCircle team2 min
- GuideEngineeringUndergraduateReact state versus props, with one small exampleWhat props and state are, who owns each, why you never change props, and how to lift state up when two components need the same data.#react#state#props#lifting state upUniCircle team2 min
- GuideEngineeringUndergraduateBuild a tiny REST API with only Node's http moduleA complete JSON API in about 25 lines with no framework, so you understand what Express does for you: routing, status codes, headers and reading a request body.#nodejs#http#rest api#jsonUniCircle team2 min
- GuideEngineeringUndergraduateThe Node.js event loop, explained for placement interviewsWhy Node can serve many users on one thread, the order in which synchronous code, process.nextTick, promises and timers run, and how to answer 'what does this print?' questions.#nodejs#event loop#microtasks#interviewUniCircle team1 min
- GuideEngineeringUndergraduateDOM events: bubbling, delegation and preventDefaultHow a click travels through the page, why one listener on a parent can handle a hundred buttons, and when to stop default browser behaviour.#javascript#dom#events#event delegationUniCircle team1 min
- GuideEngineeringUndergraduatePromises and async/await without the confusionWhat a promise is, how async and await make asynchronous code read top to bottom, how to handle errors, and how to run independent tasks in parallel.#javascript#promises#async await#error handlingUniCircle team2 min
- GuideEngineeringUndergraduateJavaScript array methods you will use every daymap, filter, reduce, find, some, every and sort explained with one small data set, plus the sort mistake that catches almost everyone.#javascript#arrays#map filter reduce#sortUniCircle team2 min
- GuideEngineeringUndergraduateJavaScript closures in 10 minutesWhat a closure is, why a function remembers the variables around it, and three places closures show up in real code and in interviews.#javascript#closures#functions#interviewUniCircle team2 min
- GuideEngineeringUndergraduatevar, let and const in JavaScript, and what hoisting really meansThe three ways to declare a variable, how their scope differs, what the temporal dead zone is, and a simple rule for which one to use.#javascript#let#const#hoistingUniCircle team2 min
- GuideEngineeringFirst yearHTML forms that work for everyoneLabels, the right input types, built-in validation and grouping: the small details that make a form usable on a phone and with a screen reader.#html#forms#accessibility#validationUniCircle team2 min
- GuideEngineeringFirst yearSemantic HTML: header, nav, main, article and why they matterHow to use HTML's meaning-carrying elements instead of a page full of divs, and what that gives you for accessibility, SEO and viva questions.#html#semantic html#accessibility#seoUniCircle team2 min
- GuideEngineeringFirst yearThe HTML page skeleton every student should knowThe handful of lines that belong at the top of every web page, what each one does, and the mistakes that make pages look broken on phones.#html#doctype#meta viewport#web basicsUniCircle team2 min
- GuideEngineeringUndergraduateWindow functions for interviews: ROW_NUMBER, RANK and running totalsThe three window-function patterns that solve most 'top N per group' and 'running total' questions in SQL interviews, with the difference between RANK and DENSE_RANK.#sql#window functions#rank#interviewUniCircle team2 min
- GuideEngineeringUndergraduateTransactions and constraints: keeping your data correctWhat BEGIN, COMMIT and ROLLBACK guarantee, what ACID means in plain words, and how PRIMARY KEY, FOREIGN KEY, UNIQUE and CHECK stop bad data at the door.#transactions#acid#constraints#foreign keyUniCircle team2 min
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