Algorithms for solving puzzles. Just for fun.

$ cd sudoku

$ gcc -std=c11 -Wall -o sudoku sudoku.c

By default the executable is built to solve 9x9 boards (SQUARE_SIDE = 3). But this may be changed by adding the custom definition of CUSTOM_SQUARE_SIDE:

$ gcc -std=c11 -Wall -DCUSTOM_SQUARE_SIDE=2 -o sudoku sudoku.c

$ ./sudoku [ - | -d ] $BOARD

d -> if included, the program will output the solving steps (e.g. for debug).

$BOARD must be a string of BOARD_SIZE * BOARD_SIZE (e.g. 81 for a standard board) characters representing the starting value of each cell, or '0' if the cell begins empty and needs to be solved, starting at the top-left going across then down. For example, a 4x4 puzzle with all but the 4th row, 3rd column cell solved would be provided:

$ ./sudoku -d 1234432121433402

Solving a 9x9 example from the internet:

$ ./sudoku 010200500500009060000015007003070001001000200900040300400780000090500008002003040