$($Please read requirements of the program carefully screenshot your output $)$

Write a Java program that performs the following tasks:

Display a friendly greeting to the user

Prompt the user for a filename $($if the file wasn$$t provided on the command line$)$

Accept that filename

Attempt to open the file

Read the $81$ numbers in the file and populate a $9$x$9$ table with them

Note: the char $*$ or $-$ is used to designate an empty spot

because $0$ is a valid entry in the hexoduko puzzle

Display the contents of the file

Solve the puzzle using the algorithm given

Display the solved puzzle, or an appropriate message if no solution is found

The rules of Sudoku:

The integers $1-9$ appear in a $9$x$9$ grid. The grid is subdivided into nine $3$x$3$ subgrids.

The thee Sudoku constraints are:

Each digit $1-9$ appears in each row, without omissions or duplicates

Each digit $1-9$ appears in each column, without omissions or duplicates

Each digit $1-9$ appears in each $3$x$3$ subgrid, without omissions or duplicates

$$Diagonal Rule$$ Sudoku adds a fourth constraint:

Each digit $1-9$ appears in each of the two long diagonals, without omissions or duplicates.

The $$isValidPuzzle$$ method need check only these constraints; if they are satisfied, we$$ll call it a $$valid$$ puzzle.

The input file will be $81$ integers, space$-$delimited. Test your program with a variety of Sudoku puzzles. They are easily found on the $$net$.$ How long does it take your program to solve the World$$s Hardest Sudoku? Or an empty puzzle?

Note that if you get the regular version working, the Super version only differs by a few lines in the isValidPuzzle method. However, be careful how you test it; most regular Sudoku puzzles aren$$t diagonal$-$rule Sudokus and you$$ll need to find specific test cases for them.

You can solve other number puzzles $($like Numbrix$)$ with this technique by dropping in the appropriate validator. The rest of the code is unchanged.

The standard solver is worth full credit; a diagonal$-$rule solver gets you an additional $10$ points. For yet another ten points there is the $16$x$16$ Hexadoku, with sixteen $4$x$4$ regions and entries in hexadecimal $(0-9$ and A$-$F$),$ and even the base$-36$ puzzle using $0-9$ and A$-$Z$.$

Note: if you are thinking ahead you can write an entirely generic Sudoku solver that will handle $4$x$4,9$x$9,16$x$16,25$x$25,$ and $36$x$36$ puzzles $($using $0-9$ and A$-$Z gets you to base $36).$ The limitations are that you run out of symbols to represent the values if you go beyond base $36,$ and the algorithm is exponential so the solve times on larger puzzles can become...large.

Throw in a Numbrix solver for yet another $10$ points. You can do Magic Squares as well, and pick up even more points.

The input file :

$8--------$

$--36-----$

$-7--9-2--$

$-5---7---$

$----457--$

$---1---3-$

$--1----68$

$--85---1-$

$-9----4--$