HclTech Berribot Assessment & Interview

Task: Given a string, return the first character that does not repeat. If all characters repeat, return '$'.

Short Explanation: Iterate through the string to count character frequencies ($O(N)$ runtime), then perform a second pass to identify the first character with a count of 1.

Short Answer: Props are read-only inputs passed from a parent component down to a child component (immutable). State is component-managed local data that can change over time and triggers re-rendering when updated.

Short Answer: Dependency Injection (DI) is a design pattern where Angular automatically creates and delivers service instances to classes (via constructors) instead of components instantiating them manually, enhancing modularity and testability.

Short Answer: The frontend client sends HTTPS requests to a Node.js/Express API Gateway. Requests pass through JWT middleware for authentication before executing service logic and reading/writing to the database.

Short Answer: Applied code-splitting/lazy loading to reduce initial bundle loading times, indexed frequently queried database columns, and cached static assets using a CDN.

Short Answer: Used centralized state stores like Redux Toolkit / Context API (in React) or NgRx (in Angular) to maintain a single source of truth and eliminate prop drilling across component trees.

Short Answer: By issuing short-lived JSON Web Tokens (JWT) upon login, storing them securely, enforcing HTTPS, and configuring server-side CORS policies alongside input validation.

Short Answer: Polymorphism means “many forms”. It allows one interface to perform different actions, such as Method Overloading (compile-time) and Method Overriding (runtime).

Short Answer: Abstraction hides complex implementation details and exposes only essential features. Encapsulation bundles data and methods into a single class unit and protects properties using access specifiers.