SUDOKU SOLVER - README I'm not a fervent sudoku solver but I always wanted to try implementing a program to solve the puzzles faster than I can. This is my first attempt. This program uses the Qt 4.x library for its user interface, you will need to have it installed to build or run the program. BUILDING INSTRUCTIONS Basic building instructions autoreconf -i mkdir build cd build ../configure make The binary will be called 'sudokusolver' and be located in the 'src' directory. You can run it from within the build directory: src/sudoku USAGE Running the program will show the main window, which consists of a basic 9x9 sudoku grid and a number of menu options. GAME menu The NEW option will clear the current game The LOAD option allows you to load a previously loaded game. The SAVE allows you to save the current sudoku puzzle to the current file. The SAVE AS allows you to save the current sudoku puzzle to a new file. The REVERT option will reload the current file from disk. The QUIT option will close the program. MOVE menu The STEP option will try to solve a single random unsolved cell, using the sudoku rules only. The GUESS option will try to solve a single random unsolved cell, and will guess (search) for a solution as required. The SOLVE RULES option will try to solve the game, using sudoku rules only. The FIND SOLUTION option will try to solve the game, and will guess (search) for a solution as required. The VALIDATE option will verify if the current puzzel is valid. SAVE GAME FILE FORMAT The file format is extremely simple: the files can be opened and edited with a text editor. Note that unsolved positions are saved too and are indicated by zeroes. Example: 0 0 0 8 0 2 9 0 0 0 0 0 9 0 7 3 6 0 4 0 9 0 0 0 0 0 7 0 8 0 0 0 5 0 4 6 1 3 0 0 7 8 0 0 0 0 0 0 2 0 0 0 7 0 3 4 6 1 2 0 7 0 0 0 1 0 0 0 0 6 0 2 0 5 0 0 8 0 0 0 0 While the file format is optimized for readability, the program will actually ignore extra whitespace while loading a file. This allows you to load games from a simple file with a sequence if 81 numbers. ALGORITHM The constraint solver will try to find a solution by applying two sets of sudoko constraints: the sudoku elimination rules, where every number from 1 to 9 can only appear once in every row, column and subgrid, and the sudoko inclusion rules, where every number has to appear exactly once in every row, column and subgrid, The search solver will apply constraints until there are no cells left with a unique solution. From there, it will pick a random unsolved cell and fill it with one of the remaining possibilities. From there it recurses into the next iteration. COPYRIGHT This sudoku solver was written by Stijn "Ingar" Buys and is available under the terms and conditions of the GNU Public License, version 3 or higher. Copyright (c) 2012-2013 ingar@osirion.org http://ingar.satgnu.net