Where to Go From Here

Phase 1 covered the vocabulary (OOP fundamentals, SOLID, the 15 most interview-relevant GoF patterns), the process (the five-step framework), and eight fully worked case studies. The single highest-leverage next step is deliberate practice on prompts you have not seen worked out for you - recognizing a pattern you already know inside an unfamiliar problem is the actual skill being tested, and it only builds through repetition on new problems.

Each of these maps cleanly onto patterns and techniques from this course - try designing one, cold, with a timer, before checking which patterns you reached for against the list below.

• -Design a Library Management System (borrowing/returning, holds, overdue fines - Composite for catalog categories, State for a book's checked-out/available/on-hold lifecycle)
• -Design an ATM Machine (State for the transaction flow, Command for transaction history/reversal)
• -Design a Restaurant Reservation System (the same time-boxed hold shape as Movie Ticket Booking, applied to tables instead of seats)
• -Design a File System / Directory Structure (Composite, directly - files and folders needing uniform treatment)
• -Design an Online Auction System (Observer for outbid notifications, State for auction lifecycle - open, closing, closed)
• -Design a Text Editor with Undo/Redo (Command, directly - and Composite if you model formatting spans as a tree)
• -Design a Hotel Booking System (nearly identical shape to Movie Ticket Booking - rooms instead of seats, date ranges instead of showtimes)
• -Design a Job Scheduler (Command for queued jobs, Strategy for scheduling policy - priority, FIFO, round-robin)

Phase 2 shifts from object-oriented class design to database schema design - a genuinely different skill, and one that pairs directly with ScaleDojo's LLD Lab (the 80-level, movie-themed schema design challenges you may have already explored). Where Phase 1 had no labBridge because no matching Lab levels existed, every module in Phase 2 ends with real Lab levels to practice against immediately - normalization, relationships, and constraints in the Titanic act, all the way through planet-scale sharding in The Matrix act.

The two phases share more than the "LLD" name suggests: both are fundamentally about managing complexity through the right structural decisions - just applied to classes and objects in Phase 1, and to tables and relationships in Phase 2.