A sudoku solver.
Input in a 9x9 grid of a Sudoku board with a "." as a unknown cell and an integer from 1-9 as a known cell.
Example:
...1.5...
14....67.
.8...24..
.63.7..1.
9.......3
.1..9.52.
..72...8.
.26....35
...4.9...
OR
...1.5...14....67..8...24...63.7..1.9.......3.1..9.52...72...8..26....35...4.9...