Daily Coding Challenges & Projects

Frontend Mini Project Challenge

CSS Animation Challenge:

Challenge:

• Create a "Pulse" Animation for a Notification Bell

Task:

• Use only CSS to animate a bell icon so it gently pulses every 2 seconds.
• Use @keyframes, transform, and animation-timing-function.

Try it online: CodePen Playground

Backend Challenge

Java/Kotlin

Kotlin Challenge:

• Build a File-Based Key-Value Store

Task:

• Write a simple Kotlin script to store key-value pairs in a local file.
• Support commands: set key value, get key, delete key.

Bonus: Add JSON storage support.

Database Query Challenge

Problems on SQL - HR Database :

1. Find employees who earn more than the average salary of their department.
2. List departments that have more than 5 employees who were hired in the last 6 months.

Data Structures & Algorithms Challenge

• Easy:
• Problem: Find the Second Largest Number in an Array
• Hint: Use one pass to track both largest and second largest.
• Medium:
• Problem: Find All Pairs With a Given Sum (Two-Pointer Approach)
• Hint: Sort first, then use left and right pointers.
• Hard:
• Problem: Minimum Window Substring (Sliding Window + Hash Map)
• Hint: Track character counts and use two pointers to shrink the window.

Bug of the Day

Language Focus: Java

Buggy Code:

public class Hello {
    public static void main(String[] args) {
        int[] numbers = null;
        for (int i = 0; i < numbers.length; i++) {
            System.out.println(numbers[i]);
        }
    }
}

Challenge: Find and fix the bug causing a runtime exception.

📋 Daily Micro-Project

Task: Backend

Build a RESTful API with Java + Spring Boot

• Endpoint: /api/employees
• Function: GET request returns a static list of employee JSONs
• Stretch Goal: Add filtering by department with query param

Trivia: 5 Fun Facts

1. Kotlin was developed by JetBrains and officially supported by Google since 2017.
2. CSS was first proposed by Håkon Wium Lie in 1994.
3. Java was originally called Oak.
4. SQL was initially developed at IBM in the early 1970s.
5. The first ever website is still online: info.cern.ch

Tool of the Day

Tool : Animista

Resource Roundup:

• CSS Tricks Animation Guide
• Kotlin Official Docs
• Java Spring Boot Tutorial (Baeldung)

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What are pseudo-classes in CSS?
2. How does the z-index work?
3. What is the difference between position: relative and absolute?
4. How do you optimize CSS animations for performance?

Backend :
1. Explain the JVM and how it works.
2. How does exception handling work in Java?
3. What are data classes in Kotlin?
4. What is dependency injection in Spring Framework?

Database :
1. What are aggregate functions in SQL?
2. Difference between HAVING and WHERE.
3. What is normalization and why is it important?

Others :
1. What is garbage collection in programming?
2. What are environment variables used for?

Daily Quiz Challenge

Frontend :

1. What does transform: scale(1.2) do in CSS?
2. Which property controls animation duration?
3. What’s the default position of HTML elements?

Backend :

1. What keyword is used for inheritance in Java?
2. In Kotlin, which symbol is used for null-safety (?., !!, ?:)
3. What does @RestController do in Spring Boot?

Others :

1. What SQL clause groups rows?
2. Which programming language runs on the JVM and is statically typed?

Mixed :

1. What does querySelector() do in JS?
2. What is a DTO in backend systems?
3. What is a composite primary key in SQL?

Weekly Cross-Domain Activities ( April 18 to 24, 2025 )

API of the Day:

Build a currency converter using the ExchangeRate API

• Fetch live exchange rates
• User selects currency pair and amount
• Displays converted amount instantly

Linux/DevOps Tip:

10 Commands to Monitor Server Health:

Real-World Project of the Week ( April 18 to 24, 2025 )

Project of the Week:

Build a Task Manager App with login, add/edit/delete tasks, and due date reminders

• Tech Stack Options:
• React + Node.js + PostgreSQL

Collaborative Project:

Open-source GitHub Project: Habit Tracker App** ← let users add habits, track streaks, share progress. Invite community collaboration!

Case Study:

How Trello Works Under the Hood

• Real-time updates using WebSockets
• Kanban board layout
• Offline support via IndexedDB