ZenanZha / sudoku

Solving sudoku as a SAT problem

Sudoku solver

This project solves sudoku puzzles by formulating it as a boolean satisfiability problem. It uses minisat to solve the SAT problem.

Obtaining the sovler

git  clone https://github.com/lakshayg/sudoku
cd sudoku
git submodule init
git submodule update

OR

git clone --recursive https://github.com/lakshayg/sudoku

Building the sovler

Go to the project root directory and follow these steps to compile the solver (make sure you are using g++ and not clang)

mkdir build
cd build
cmake .. && make

This will generate an executable named main in the build directory. This is the solver.

Using the solver

The solver takes a text file as the input. Some sample puzzles are provided in the demo folder. To solve a puzzle, create a text file containing the puzzle. Use 0 for blank cells. An example is shown below:

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

Now go into the build directory and use the following command

./main <path-to-puzzle-file>

This should print out the solved puzzle on the terminal screen.

+---------+---------+---------+
| 2  7  8 | 5  6  4 | 1  9  3 |
| 6  5  1 | 7  9  3 | 4  2  8 |
| 3  4  9 | 2  8  1 | 7  6  5 |
+---------+---------+---------+
| 4  1  5 | 3  2  8 | 9  7  6 |
| 8  2  6 | 9  4  7 | 3  5  1 |
| 9  3  7 | 6  1  5 | 8  4  2 |
+---------+---------+---------+
| 1  8  2 | 4  5  9 | 6  3  7 |
| 7  6  4 | 1  3  2 | 5  8  9 |
| 5  9  3 | 8  7  6 | 2  1  4 |
+---------+---------+---------+
Solved the puzzle in 3.86 ms :)