Sudoku 86 v3.1
by ~DNA~
barid42@myway.com
10-28-07

The first, and therefore the best BASIC Sudoku game on the TI-86 at time of release. 

This program is a Sudoku puzzle generator and game. The rules of Sudoku are simple: fill in the 9x9 grid so that every row, column, and 3x3 sub-grid have one and only one instance of the numbers 1 thru 9.

Features:
- 5 levels of difficulty, showing between 24 and 40 spaces as a starting point.
- 4 to 8 hints for each puzzle, based on the difficulty seting.
- Changing of the initial numbers given is not allowed.
- Option to reset board during play. This also resets the number of hints.
- Automatic save on exit.
- Running timer, resets with board, saves with game.

v3.1 improvements:
- Vastly sped-up the board generation process. Basically, the program starts with a very simple, valid Sudoku solution board. The program then, randomly, rearranges rows and columns to make the board into a (mostly) unique board. It's somewhat (to say the least) less complicated, though the uniquesness of the board can be called into question. Still, the speed of the algorithm is SEVERAL times faster at generating a good, solveable board.
- Re-added the progress meter during puzzle generation. Had been removed in version 3.0, but I felt it needed to be there.
- Bug fix (could not exit board generation with keypress)

Instructions:
- Send Sudoku86 files to your calc using any linking program. This includes the following files:
        - CURSR.86p Used to display cursor during gameplay.
        - DISPN.86p Used to display numbers on board.
        - MAKEBRD.86p Used to create the game board.
        - Sudoku86.86p Main program, run this to play.

- The first time running, no game is saved (obviously), so you'll have to select NEW at the main menu. This used to take up to 25 minutes. It now should finish within one minute at the most. (I timed it around 30 seconds or less.)

- Once created, the game will ask you to select a difficulty, one being the easiest, and 5 being the hardest. This will set how many digits are shown to begin, and also how many guesses you have (4 to 8).

- Gameplay is very simple. Arrows move your cursor, number pad sets number in space (Enter 0 to clear space.) F1 brings up a Menu, and exit quits and saves the game. The Menu gives 5 options:
        - Hint: Uses a hint if you get stuck. Displayes correct value in whatever space the cursor is in.
        - Reset: Resets the board to the original numbers given. Resets the hints, also.
        - Resume: Exits Menu and continues the game.
        - Check: When you think you have the correct answer, use this key to check and see if you're right. There is no auto-detection (Would slow down the game a LOT).
        - Exit: Quit and save the game.

- Next time you start the game, you have the option of continuing your game. You can also load a game that you've played previously. Every game is given a number, 1 thru 99999. By choosing load and entering this number, the game will generate any of the past puzzles you've played. It is possible (though not likely) that two puzzle numbers may generate identical puzzles. The same puzzle can be played with different difficulty levels with this method. Note: loading a game does not cut down on the amount of time needed to generate the puzzle (though the generation time is way better than it was).

Games are saved by the file SUDO86.86m. Deleting this file will get rid of your saved game. All other variables used are wiped on exit.

If you have any questions, feel free to e-mail me. I appreciate any and all feedback.

Future improvements:

Aside from the generation speed (which is now done), I don't plan on making any changes unless someone has a decent suggestion. Gameplay is, in my opinion, about as good as it can get, and I tried to include as many features as I could. 

If you have any interest in porting this game to ASM or other calcs, please let me know ahead of time and give me some small credit for the work I've done.

Thanks, and enjoy.