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
35 tips
- ChecklistEngineeringCoding interview day: a checklist for before, during and afterWhat to prepare the night before, a step-by-step routine for solving a problem in front of an interviewer, and what to do when you get stuck.#interviews#placements#coding round#checklistUniCircle team2 min
- ChecklistEngineeringUndergraduateA six-week DSA plan for placement seasonA week-by-week checklist that takes you from arrays to dynamic programming before campus placements, with a weekly target and how to revise.#dsa#placements#study plan#interview preparationUniCircle team2 min
- TipEngineeringUndergraduateBig-O in practice: will my solution pass the time limit?How to read input limits and estimate whether an O(n²) or O(n log n) solution fits within a typical one-second limit, with the operation counts worked out.#dsa#big-o#complexity#competitive programmingUniCircle team2 min
- 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
- TipEngineeringFirst yearJava String, the string pool and StringBuilderWhy Strings never change, why == on Strings is a classic bug, and when StringBuilder makes your code dramatically faster.#java#strings#stringbuilder#immutabilityUniCircle team1 min
- TipEngineeringUndergraduateJava equals and hashCode: the contract and why HashSet breaks without itWhat equals and hashCode must promise each other, a short demo of a HashSet holding 'duplicates' when hashCode is missing, and how records do it for you.#java#equals#hashcode#oopUniCircle 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
- TipEngineeringUndergraduateControlled and uncontrolled form inputs in ReactThe difference between inputs whose value lives in React state and inputs the browser manages, when to use each, and the warning you get when you mix them.#react#forms#controlled components#inputsUniCircle team1 min
- TipEngineeringUndergraduateLists and keys in React: why the index is usually the wrong keyHow React uses keys to match list items between renders, what goes wrong with array indexes as keys, and how to pick a good key.#react#lists#keys#renderingUniCircle team1 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
- TipEngineeringUndergraduateNode.js modules: CommonJS (require) versus ES modules (import)The two module systems you will meet in Node.js projects, how to tell which one a file uses, and the errors you get when you mix them.#nodejs#modules#require#importUniCircle team1 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
- TipEngineeringUndergraduateThe this keyword in JavaScript, explained with four rulesHow this is decided at call time, why arrow functions behave differently, and how to fix the lost-this bug in callbacks.#javascript#this#arrow functions#bindUniCircle 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
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