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
10 tips
- 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
- 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
- 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
- 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
- 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
- TipEngineeringUndergraduate== versus === and truthy values in JavaScriptWhy loose equality surprises people, the short list of falsy values, and safe ways to check for missing values with ?? and ?.#javascript#equality#truthy#nullishUniCircle team1 min
- TipEngineeringFirst yearLinks, images and data attributes: small details that matterWriting link text people can understand, alt text that actually helps, safe links that open new tabs, and how data-* attributes connect HTML to your JavaScript.#html#links#alt text#data attributesUniCircle team2 min
- TipEngineeringFirst yearHTML tables done right: caption, headers and scopeWhen to use a table, how to mark up header cells so the data makes sense to everyone, and why tables should never be used for page layout.#html#tables#accessibilityUniCircle team1 min
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