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Generating Solvable Puzzles

 A separate, stand-alone, fully-functional utility has been provided that can generate 9x9 Sudoku puzzles from a store of over 50,000 puzzles.    The utility consists of a singleton utility class GeneratePuzzle and a companion GUI application to run it, GeneratePuzzleApp}.   The utilities utilize the files in the {{HW11\data\puzzle_src folder.

1. .In DrJava, right-click the {{GeneratePuzzleApp} class and select "Run File" to start the utility.
2. Select a file from the drop-list (yes, 4,txt is missing--broken link on the download page).   The higher the number, the harder the puzzles.
3. Each file contains about 10,000 puzzles.   Use the number spinner to choose or type a puzzle number from 1-10,000 (approx.).    Specifying "0" as the index will cause the utility to randomly select a puzzle.
4. Click the Generate button and the puzzle will appear in the main display area of the utility.  
5. Click the Save button to save the generated puzzle in a format that the Sudoku solver application can now read. 

This should keep you busy for a while, though your Sudoku solver should be able to easily solve any puzzle in the collection.

Note:  Your Sudoku solver should be able to solve a completely blank puzzle (all dashes, not empty)!

Programming Tips

Mutating a value outside of an anonymous inner class:

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As any seasoned Sudoku player knows, there are other reduction rubrics that can be applied to more quickly reduce a board.   For instance, if an unsolved cell includes a value choice that no other unsolved cell in its cell contains, then the cell must have that value (this can be extended to a sub-set of values spread across multiple cells in a cell set).    Can you incorporate additional reduction rubrics in a modular, flexible and extensible fashion?

Challenge!  Come up with a Sudoku puzzle (any order) that your solver can solve but the staff's solution cannot!

Submission

Submit via Owlspace a .zip file containing the entire HW11 folder, including all the support code and data.  Don't forget to add as header to the GameModel class, your names and ids.