Course Roadmap

This roadmap details your learning journey through the Low-Level Design curriculum. The roadmap is structured sequentially to build your fundamentals first, before exposing you to complex software design patterns and real-world system modeling.

1. Learning Objectives

• Identify all 13 core modules of the LLD curriculum.
• Understand the recommended sequencing and pacing strategy.
• Recognize the criteria to evaluate your mastery at each milestone.

2. Problem Statement

Many developers fail LLD interviews because of a fragmented learning approach. Learning design patterns without knowing class relationships, or trying to design a parking lot without solid knowledge of encapsulation leads to unstructured, buggy code. This roadmap resolves learning fatigue by laying out a progressive, layered path.

3. Real-world Analogy

4. Theory

The roadmap covers 13 major modules spanning several logical stages:

• Stage 1: Foundations (Modules 1-5): LLD basics, object-oriented concepts, and core class relationships.
• Stage 2: Design Rules (Module 6-7): SOLID Principles and Unified Modeling Language (UML) notation.
• Stage 3: Blueprints & Patterns (Modules 8-10): Creational, Structural, and Behavioral Gang of Four patterns.
• Stage 4: Advanced Systems (Modules 11-13): Concurrency paradigms, LLD interview framework, and 6 full case studies.

5. Visual Diagram

The block diagram below visualizes your curriculum roadmap:

6. Syntax Explanation

Throughout the course, we will structure code examples with consistent module packages to simulate real-world developer workspaces.

• In Java, code resides under package com.revisealgo.lld; namespaces.
• In Python, code utilizes module files structured inside directory packages.
• In C++, classes are organized using namespaces like namespace ReviseAlgo::Lld.

7. Step-by-Step Implementation

To get the most out of the course roadmap:

• Step 1: Read the theoretical overview of each topic to understand the core concept.
• Step 2: Analyze the visual UML / Excalidraw architecture diagrams carefully.
• Step 3: Review the clean code snippets in Java, Python, and C++.
• Step 4: Solve the practice exercises, write the code in the playground, and complete the quizzes to test your understanding.

8. Complete Code

Below is a boilerplate setup for tracking course milestones. It demonstrates object tracking across languages.

9. Code Walkthrough

In the tracker code above, we encapsulate the milestone state (title and completed) within a class. This restricts external modification and ensures status updates go through a controlled public method complete().

10. Execution Flow

• Instantiate three unique Milestone objects on the heap.
• Collect references to these milestones in an array/list.
• Call the method complete() on the first milestone.
• Iterate through the array, resolving status strings and writing them to console output.

11. Internal Working

When objects are loaded into a system's runtime memory, the class definitions (methods and structure blueprints) are loaded into the Method Area. Every time you run new Milestone(), a new allocation block for that object is carved out of the Heap Area, while variable references are managed in individual thread Stack frames.

12. Complexity Analysis

• Time Complexity: $O(N)$ where $N$ is the number of milestones to list.
• Space Complexity: $O(N)$ to store the array of milestones in memory.

13. Best Practices

• Do not skip prerequisites: Master UML notation and basic OOP before designing concurrency modules.
• Commit code daily: Apply design rules in writing rather than just reading concepts.
• Participate in code reviews: Compare designs with other students in the community.

14. Common Mistakes

• Skipping basic topics like Aggregation vs Composition.
• Memorizing design patterns instead of understanding the real-world problems they solve.

15. Interview Questions

16. Practice Exercises

• Easy: List all modules you plan to complete this week.
• Medium: Add a progress percentage calculation helper to the RoadmapTracker code block.
• Hard: Modify the RoadmapTracker class to write milestone statuses to a mock file database.

17. Challenge Problem

Design a custom learning schedule class that takes a user's target date, dynamically calculates the required study pacing, and outputs a daily syllabus schedule.

18. Summary

• The roadmap is composed of 13 modules divided into logical phases.
• Practical coding exercises and quizzes should be solved alongside theory.
• Case studies serve as the ultimate evaluation of your skills.

19. Cheat Sheet

Phase	Focus Modules	Suggested Duration
1. Foundations	Modules 1 to 5	2 Weeks
2. Principles & UML	Modules 6 & 7	2 Weeks
3. Design Patterns	Modules 8 to 10	4 Weeks
4. Concurrency & Practice	Modules 11 to 13	4 Weeks

20. Quiz

21. Next Lesson Preview

In the next lesson, we will cover how to Join the Community to collaborate with peers, ask questions, and share code reviews!