A sudoku resolver.
Learn backtracking, kind of a "smart brute-force".
gcc -o solve_sudoku main.c print_sudoku.c
./solve_sudoku ".8.1....." "6....48.." "35426.791" "293.8...4" "...7.9..." "7...4.965" "829.57613" "..78....9" ".....6.8."
9 8 2 1 7 3 5 4 6 6 7 1 5 9 4 8 3 2 3 5 4 2 6 8 7 9 1 2 9 3 6 8 5 1 7 4 5 4 6 7 1 9 3 2 8 7 1 8 3 4 2 9 6 5 8 2 9 4 5 7 6 1 3 4 6 7 8 3 1 2 5 9 1 3 5 9 2 6 4 8 7