Daily Coding Challenges & Projects

Frontend Mini Project Challenge

Theme : CSS Animation Effects

CSS Animation Challenge : “Floating Card Hover Effect”

Create a CSS animation where a card floats upward and casts a soft shadow when hovered.

Requirements :

• Use only HTML + CSS
• Card should slightly move up (transform: translateY(-10px))
• Smooth transition (0.3–0.5s)
• Add glowing shadow on hover

Playground Suggestion :CodePen / JSFiddle / CodeSandbox

Backend Challenge

Focus : Java & Kotlin

Java Challenge :

Problem : Write a Java function to remove duplicate characters from a string while preserving order

Example :

Input: "programming" → Output: "progamin"

Kotlin Challenge :

Problem : Create a Kotlin function to parse a CSV line into fields, correctly handling:

• quoted values
• commas inside quotes
• empty fields

Example :

"John, \"New York, USA\", 25,,Student"

Database Query Challenge

Problems on SQL - HR Database :

1. Write a SQL query to find employees hired in the last 120 days.
2. Write a query to list employees whose salary is below the departmental average salary.

Data Structures & Algorithms Challenge

• Easy : "Find the Index of First Unique Character"
• Problem : Given a string, return the index of the first non-repeating character.
• Hint :
• Use frequency counting
• Traverse twice:
• Count
• Find first with count = 1
• Medium : "Sort Colors (0s, 1s, 2s)"
• Problem : Sort an array containing only 0, 1, 2 without using in-built sort.
• Hint :
• Use Dutch National Flag Algorithm (3 pointers)
• One pass solution
• Hard : "Recover a Corrupted BST"
• Problem : Two nodes of a BST have been swapped. Restore the BST without modifying structure.
• Hint :
• Use in-order traversal
• Identify misplaced nodes
• Swap values

Bug of the Day

Focus : — Java & Kotlin

Buggy Code ( Java ) :

public class Test {
    public static void main(String[] args) {
        int[] arr = {1,2,3};
        for(int i = 0; i <= arr.length; i++) {
            System.out.println(arr[i]);
        }
    }
}

Challenge : Find the bug & fix it.

Buggy Code ( Kotlin ) :

fun add(a: Int, b: Int): Int {
    return a + b!!
}

Challenge : Find the bug & fix it.

📋 Daily Micro-Project

Focus : Backend

Task :

“Build a Simple Login API (Java or Kotlin)”

Requirements :

• /login POST endpoint
• Accepts JSON { "username": "...", "password": "..." }
• Validate against hardcoded credentials
• Respond with :

{ "status": "success", "token": "<random-string>" }

• If invalid → return error message

Bonus : Allow CORS for frontend integration.

Trivia: 5 Fun Facts

1. The name Java was inspired by a type of coffee from Indonesia.
2. CSS animations were first widely adopted after CSS3 standardization.
3. Kotlin became an official Android language in 2017.
4. SQL was originally called SEQUEL (Structured English Query Language).
5. The first web page ever created is still online at CERN.

Tool & Resource of the Day

Tool : “Figma for UI Design”

• Perfect for building UI prototypes
• Offers free collaborative features
• Ideal for frontend developers creating animations & transitions

Resource Roundup ( "CSS Animation Learning Pack" ) :

• MDN — CSS Animations Guide
• Animista — Prebuilt CSS animations
• CSSTricks — Animation tutorials
• CodePen — Explore thousands of animation examples

Interview Question of the Day

Daily Interview Questions

Frontend :
1. What is the difference between transition and animation in CSS?
2. How does CSS transform differ from translate?
3. What is GPU-accelerated animation?
4. Explain the concept of easing functions in animations.

Backend :
1. Explain the difference between JDK, JRE, and JVM.
2. What is a Kotlin data class?
3. How does memory management work in Java’s garbage collector?
4. What is the difference between var and val in Kotlin?

Database :
1. What is a composite primary key?
2. Explain the difference between GROUP BY and PARTITION BY.
3. What is a correlated subquery?

Others :
1. What is a virtual machine? Provide an example.
2. What is CI/CD?

Daily Quiz Challenge

Frontend :

1. What does animation-iteration-count: infinite; do?
2. Which CSS property sets the speed at which an animation progresses?
3. What is the default value of animation-fill-mode?

Backend :

1. What keyword is used to create a class in Kotlin?
2. What is method overloading?
3. Which Java collection does not allow duplicates?
• List
• Set
• Queue

Database :

1. Which SQL clause is evaluated last?
• WHERE
• GROUP BY
• ORDER BY

Other :

1. Which protocol does SSH use for secure communication?

Mixed Quiz :

1. JS : What is the output of console.log(typeof null)?
2. Java : What is the size of int in Java?
3. SQL : What is the purpose of HAVING?

Weekly Cross-Domain Activities ( November 28 to December 04, 2025 )

API of the Day:

Use the Currency Exchange API to convert an amount between currencies.

Linux / DevOps Tip :

Run server health check :

top  
htop  
df -h  
du -sh *  
free -m  
uptime  
journalctl -xe  
systemctl status <service>

Real-World Project of the Week ( November 28 to December 04, 2025 )

Project of the Week:

Build a URL shortener app ( frontend + backend + database ).

Collaborative Project :

Join an open-source project:

“Awesome-DSA-Practice”

(Create algorithms + solutions in multiple languages.)

Case Study :

Analyze how Spotify recommendation engine works.

Users replicate the feature using:

• Cosine similarity
• TF-IDF
• Collaborative filtering