LLD Mastery - SOLID + 10 Design Patterns with Aman Saxena

Stuck on where to even start with LLD? This is your one-stop resource.

No need to spend hours hunting through YouTube videos or scattered blogs. These notes take you from zero to advanced — SOLID principles + 10 must-know design patterns, explained properly.

What makes these notes different:

• Every pattern starts with why — why does this problem exist, why does this pattern solve it, not just "here's the syntax"
• Clean, well-formatted notes — easy to read, easy to revisit
• Full code examples in both Java and C++ for every single pattern
• Covers: SOLID Principles, Strategy, Factory, Singleton, Observer, Decorator, Builder, Adapter, State, Command, Chain of Responsibility

Read these carefully, and you won't need to look anywhere else for LLD theory.

What you'll walk away with: complete clarity on SOLID principles and design patterns — the "what" and the "why" fully sorted.

What's still on you: practice. Understanding the concepts is step one — solving actual LLD problems is step two, and that takes repetition. You probably won't nail your first few LLD problems even after this, and that's normal. This gives you the foundation; the reps build the muscle.