After learning backtracking concept during 42_Piscine I decided to write a program in C to solve any 9x9 Sudoku using this technique.

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

First of all, clone the repository on your computer

git clone https://github.com/jesuserr/Sudoku_solver.git

and then execute 'Make' inside the newly created ´Sudoku_solver' folder to compile the program

cd Sudoku_solver/ && make

In order to run the program, execute it as shown below

./sudoku_solver .15.....2.....2.4..9....6.15.....4..42..3.9...634...8..86.25........3.6..4......8

The output should show the initial Sudoku and the solution found:

Initial Sudoku:
.15 ... ..2 
... ..2 .4. 
.9. ... 6.1 

5.. ... 4.. 
42. .3. 9.. 
.63 4.. .8. 

.86 .25 ... 
... ..3 .6. 
.4. ... ..8 

Solution Found:
815 364 792 
637 912 845 
294 578 631 

579 286 413 
428 731 956 
163 459 287 

986 125 374 
752 843 169 
341 697 528 

• Visual Studio Code

• Sudoku Generator for testing - In 'Output format' choose the option 'One line' to obtain the Sudoku in proper format to feed the program.
• Python Sudoku Solver - Computerphile - Video from Computerphile explaining backtracking algorithm to solve Sudoku in Python.
• Solving Every Sudoku Puzzle - Essay from Peter Norvig dealing with Sudoku solving algorithms.
• Backtracking - Wikipedia - Wikipedia entry for Backtracking.