C-based simple 9x9 sudoku solver
Input like:
0 0 0 0 0 3 0 5 0 0 9 0 2 0 7 0 0 0 6 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 2 0 0 5 0 0 0 8 0 0 0 0 0 0 0 0 0 0 3 0 9 0 0 0 0 0 0 7 2 0
or
X X X X X 3 X 5 X X 9 X 2 X 7 X X X 6 X X X X X X 1 X X X X X 1 X X X 4 X X X X X X X X X X X 3 X X X 2 X X 5 X X X 8 X X X X X X X X X X 3 X 9 X X X X X X 7 2 X