# Sudoku solver
A simple sudoku problem solver because I got bored of solving them manually.

## File format
The sudoku solver accepts a file for the following format:
* Each row consists of 9 characters (+ newline)

* Each character on a row (aside from newline) must be '0'-'9' or ' ' (if value is unknown)

* There must be a total of 9 rows

For example, a file might look as follows:
```
 23456789
2 4567891
34 678912
456 89123
5678 1234
67891 345
789123 56
8912345 7
91234567 
```

or

```
123456789
2 456 891
3456789  
456 89123
5678 12 4
6  91 345
789123456
8 12345 7
912345678
```


## Compiling and running
To test the functionality, simply run `gcc -o sudoku main.c board.c`, then
`./sudoku [filename]`, where the given file is formatted according to the
aforementioned specifications.

## Optimization
An optimization directive has been included in `board.c` to allow for the near
complete removal of boundary checks and error conditions. To enable this
optimization, simply add `-DOPTIMIZE` to your compiler flags.

## TODO

* Optimizations

  * Per-quadrant bit-field of populated values

  * Packed structures

  * Better structure layouts

* Better error messages

* Makefile