Sudoku Solver using Constraint Satisfaction Problem (CSP)

This project is a Sudoku solver implemented in Java using the Constraint Satisfaction Problem (CSP) approach. It reads a Sudoku puzzle, applies CSP techniques to solve it, and verifies the solution.

Features

• CSP Techniques: Utilizes techniques such as elimination, single possible number, only choice in row/column/box to solve the puzzle.
• Efficient: Designed to solve puzzles efficiently with performance statistics.
• Modular Design: Clear separation of different CSP techniques for better readability and maintainability.

Technologies Used

• Java: The programming language used for the implementation.
• Eclipse/IntelliJ: Recommended IDEs for development.

Getting Started

Prerequisites

• Java Development Kit (JDK) installed (version 8 or above).
• An IDE like Eclipse or IntelliJ IDEA is recommended for running the project.

Installation

1. Clone the Repository

   git clone https://github.com/yourusername/sudoku-csp-solver.git
   cd sudoku-csp-solver

2. Open the Project in Your IDE

   Open the cloned project in your preferred IDE.

3. Run the Project

   Locate the SudokuCSP.java file and run it.

Usage

1. Define the Sudoku Puzzle

   The Sudoku puzzle to be solved is defined in the firstSudoku 2D array in the SudokuCSP.java file. Modify this array to solve different Sudoku puzzles.

   public static int[][] firstSudoku = {
       {5, 0, 1, 0, 0, 0, 6, 0, 4},
       {0, 9, 0, 3, 0, 6, 0, 5, 0},
       {0, 0, 0, 0, 9, 0, 0, 0, 0},
       {4, 0, 0, 0, 0, 0, 0, 0, 9},
       {0, 0, 0, 1, 0, 9, 0, 0, 0},
       {7, 0, 0, 0, 0, 0, 0, 0, 6},
       {0, 0, 0, 0, 2, 0, 0, 0, 0},
       {0, 8, 0, 5, 0, 7, 0, 6, 0},
       {1, 0, 3, 0, 0, 0, 7, 0, 2},
   };

2. Run the Solver

   Run the SudokuCSP.java file. The program will display the initial Sudoku puzzle, solve it, and then display the solved puzzle along with the time taken.

Project Structure

• Cell.java: Defines the Cell class representing each cell in the Sudoku grid.
• SudokuCSP.java: Main class implementing the CSP solver.

Example Output

---------------------------------------------
 5 0 1 0 0 0 6 0 4
 0 9 0 3 0 6 0 5 0
 0 0 0 0 9 0 0 0 0
 4 0 0 0 0 0 0 0 9
 0 0 0 1 0 9 0 0 0
 7 0 0 0 0 0 0 0 6
 0 0 0 0 2 0 0 0 0
 0 8 0 5 0 7 0 6 0
 1 0 3 0 0 0 7 0 2
---------------------------------------------

SUDOKU IS CORRECTLY SOLVED!!!
---------------------------------------------
 5 3 1 2 7 8 6 9 4
 2 9 4 3 1 6 8 5 7
 6 7 8 4 9 5 2 1 3
 4 2 6 7 5 1 3 8 9
 3 5 7 1 6 9 4 2 8
 7 1 9 8 4 2 5 3 6
 9 4 5 6 2 3 1 7 8
 8 8 2 5 3 7 9 6 1
 1 6 3 9 8 4 7 4 2
---------------------------------------------
Sudoku Solved in : 123 ms