Sudoku 9×9 – Programming II Project

A Java-based Sudoku 9×9 desktop application built using MVC architecture, design patterns, and Swing GUI as part of the Programming II course.

The system supports:

• Loading and playing Sudoku games from CSV files
• Generating new games by difficulty
• Validating and solving boards
• Saving and resuming unfinished games
• Undoing moves
• Clear separation between frontend, controller, and backend logic

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🎮 Features

🧩 Gameplay

• Load Sudoku boards from CSV files
• Interactive 9×9 grid with validation
• Undo last move
• Check solution correctness
• Solve puzzle (only when exactly 5 cells are empty)

📂 Game Management

• Generate new games (Easy / Medium / Hard) from a valid solution
• Save unfinished games automatically
• Resume unfinished games from catalogue
• Automatically deletes solved games

🧠 Validation & Solver

• Detects VALID / INVALID / INCOMPLETE boards
• Row, column, and 3×3 box validation
• Solver uses permutation-based logic (for limited empty cells)

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🧱 Architecture

The project follows a View–Controller architecture with external facades:

• Frontend (View)
  Swing GUI panels (ViewTable, CatalogueScreen, PlayPanel)

• Controller (Facade / Coordinator)
  GameDriver acts as the central interface between UI and backend logic

• Backend (Model & Services)
  Board storage, validation, generation, solver, CSV persistence

Design Patterns Used

• Facade – GameDriver
• Singleton – csvManager
• Flyweight – Solver board view abstraction
• Iterator – Permutation generation
• Command-like Undo Stack – Move tracking

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📁 Project Structure

src/
├── backend/
│ ├── csvManager.java
│ ├── GenerateGame.java
│ ├── SequentialValidation.java
│ ├── SudokuSolver.java
│ ├── RandomPairs.java
│ ├── ValidationResult.java
│ ├── Difficulty.java
│ ├── Validity.java
│ └── InvalidGame.java
│
├── controller/
│ ├── GameDriver.java
│ └── SolverService.java
│
├── frontend/
│ ├── ViewTable.java
│ ├── CatalogueScreen.java
│ ├── PlayPanel.java
│ └── Test.java
│
└── main/
└── FrameManager.java

📦 Storage Layout

SudokuStorage/
├── 1-EASY/
├── 2-MEDIUM/
├── 3-HARD/
└── 4-INCOMPLETE/

All boards are stored as CSV files.