Sudoku Solving

[fireflybob]

Have been quite addicted to Sudoku puzzles for a while - they help to pass away the longer sectors!

There is at least one site on the web which will solve any 9 x 9 Sudoku and I was wondering how they go about writing a program to solve them?

I am also looking for software which will solve a 12 x 12 Sudoku.

[BOAC]

Another 'semi-addict' here, ffb, :{ and I would be interested to know how the designer knows which and how many squares to empty to make a particular 'grade' of puzzle. I find a combination of a Suduko and a cryptic crossword an excellent antidote to 'dead brain' (although there are some who would say....:))

No doubt one of our clever clogs will have a link to a writing programme or perhaps even written one!

[Bushfiva]

I am also looking for software

You naughty boy. As punishment, go solve the (unfortunately named) Qassim Hamza sudoku.

[Clarence Oveur]

On Wiki there is plenty of info on how to do.

[windriver]

Sudoku isn`t my thing... but as it happens I`m doing some video tutorials for some software that, apart from being the best Crossword Software I`ve ever used has a function for compiling and publishing Sudoku puzzles...

Thanks windriver, but IAW forum rules I have had to remove the link to a 'commercial' website and ask folk to Google for 'crossword compiler':)

[VH-WTF]

For the really long sectors, try these (http://www.samurai-sudoku.com/).:8

[Geezers of Nazareth]

In a previous life I used to be a computer programmer, so I can give you the basic idea behind the 'solver' programs...

Working on the basis of the original 3x3 Sudoku grid ...

1. the program, internally, starts off with a 9x9 grid, where each little bit of the grid starts of containing all the numbers 1-9.
2. you enter the numbers that you already have from the original grid, the program deletes all the matching numbers from each row and each column, and each specific 3x3 region.
3. Once you have entered all your starting numbers the program can then display all those locations which have only one possible 'missing' number.

Assuming that the program shows you which is the missing number from a particular row or column, you then enter it back into the grid on the computer, as in number '2' above. Which then leads to number '3', which then leads to number '2', and so on.

That is it, in a nutshell. There is no magical hidden algorithm to help you solve a Sudoku, it is just a few steps repeated time and time again. The same principle holds true for all sizes of Sudoku grid.



There are two kinds of 'solver' program - one which just provides the finished grid, and one which provides you with a clue to a particular number in a particular square as a hint. I prefer/use the 'hint' version.

[TheGorrilla]

Surely the fun is in solving the sudoku yourself rather than making a computer do it. May as well start off with a grid that's full to start with!

[oz in dxb]

there's a program called "simple sudoku". It allows you to play the game and brings up the candidates to help you to solve the puzzle. You can also load your own game (from a newspaper/magazine). It will give you hints on how to solve the game.

Use google search to find it
Oz

[cats_five]

Computers can solve any Suduko by brute force.