Javarena: DSA, LLD & HLD in Java

Welcome to Javarena – a structured, Java-based repository crafted to help you master coding interviews and * system design* with real-world examples, design patterns, and company-specific problem tracking.

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📌 Table of Contents

• 🎯 Overview
• 📁 Project Structure
• 📘 DSA Topics
• 🏢 Company-Wise Problems
• 🧩 Low-Level Design (LLD)
• 🏗 High-Level Design (HLD)
• 🚀 Getting Started
• 🏷️ Badges

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🎯 Overview

This repository includes:

• ✅ Data Structures & Algorithms (DSA) – Topic-wise and company-wise curated problems from LeetCode, * GeeksforGeeks*, etc.
• 🏢 Company-Wise Tracking – Solved and categorized interview problems for top tech companies like Amazon, Adobe, Google, etc.
• 🧩 Low-Level Design (LLD) – Core OOP design patterns with hands-on examples. (In Progress)
• 🏗 High-Level Design (HLD) – Scalable architecture design with trade-offs and system diagrams. (In Progress)

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📁 Project Structure

src/
└── main/
└── java/
└── org/
└── example/
├── coding/ # DSA by topic
├── companies/ # DSA by company
├── lld/ # Low-Level Design
└── hld/ # High-Level Design

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📘 DSA Topics

#	Topic
1	Algorithms
2	Array
3	Linked List
4	Stack & Queue
5	Graph
6	Segment Tree

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🏢 Company-Wise Problems

Solve company-tagged questions like real interviews and track your progress here:

Company	File
Amazon	Amazon.md
Adobe	Adobe.md
Google	Google.md
Microsoft	Microsoft.md
More...	📁 View all

Each file contains:

• 🎯 Problem link
• 📂 Solution file path
• ⚡️ Difficulty & topic tags

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🧩 Low-Level Design (LLD)

📚 Basics

#	Pattern Name	Description
1	LLD Basics	OOPs & LLD basics

🔨 Creational Design Patterns

#	Pattern Name	Description
1	Singleton	Ensure a class has only one instance and provide a global point of access to it.
2	Builder	Separates complex object construction from its representation.
3	Factory	Creates objects without exposing the instantiation logic.
4	Prototype	Create new objects by copying existing ones, reducing the cost of creation.
5	Abstract Factory	Provides an interface for creating families of related or dependent objects without specifying their concrete classes.

🧠 Behavioural Design Patterns

#	Pattern Name	Description
1	Chain Of Responsibility	Passes a request along a chain of handlers until one of them handles it.
2	Observer	Defines a one-to-many dependency so that when one object changes state, all its dependents are notified and updated automatically.
3	Strategy	Enables selecting an algorithm's behavior at runtime by encapsulating it within a class and making it interchangeable.
4	Command	Encapsulates a request as an object, thereby allowing users to parameterize clients, delay execution, or queue and log operations.
5	State	Allows an object to change its behavior when its internal state changes, appearing as if it changed its class.

🧱 Structural Design Patterns

#	Pattern Name	Description
1	Decorator	Dynamically adds new behavior to objects at runtime.

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🏗 High-Level Design (HLD)

Concepts

• Database Design and Databases
• Consistency Patterns
• Isolation Level
• Cache
• Networks & Communication
• Rate Limiting

#	System	Status	Description
1	URL Shortener	🛠 In Progress	Service decomposition planned
2	WhatsApp Clone	🛠 In Progress	Scalable chat architecture

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🚀 Getting Started

git clone https://github.com/piyush7199/javarena-dsa-design.git
cd javarena-dsa-design

Open in your favorite IDE (IntelliJ or VSCode recommended for Java).

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🏷️ Badges