Sudoku

Liazon · Post by **Liazon** » Wed 16 Nov, 2005 10:51 pm

Anybody like sudokus? I was doing a few today and I thought, "This is really addictive."

For those of you who don't know sudoku, they are Japanese number puzzles. You have to arrange the digits 1-9 in a 9x9 table/matrix so that each row has each digit only once, each column has each digit only once, and each of the 9 3x3 tables that the 9x9 can be divided into only has each digit once.

google it on the net cuz right now they're suppose to be super popular in Europe.

I was thinking why not make a program that generates a random sudoku puzzle and you can try to solve it on the calc?

If anybody likes this idea, I'd like to reserve it for myself when I get better at ASM.

coelurus · Post by **coelurus** » Wed 16 Nov, 2005 11:10 pm

Those were everwhere here in Sweden a little while ago. I've tried a few times but I don't like number crunching so I still haven't solved a single one

A friend of mine made a Java applet that generates and solves those puzzles using brute force afaik:

http://www.dd.chalmers.se/~haner/sudoku.html

Liazon · Post by **Liazon** » Wed 16 Nov, 2005 11:18 pm

my opinion is that sudokus r more like complex logic. still, once u start one u just don't want to put it down. maybe that's a bad thing.

Post by **kv83** » Wed 16 Nov, 2005 11:19 pm

Indeed, I was planning to pick up sudoko right after I finish Slippy. I already have the methods and stuff for making sudoko's random. So unlimited ammount of sudoko's. Stay tuned.

Sorry that I already had the same idea...

Liazon · Post by **Liazon** » Wed 16 Nov, 2005 11:22 pm

ok, you can make the game. i still need to learn ASM

kalan_vod · Post by **kalan_vod** » Wed 16 Nov, 2005 11:31 pm

I'm almost positive there is one in basic on ticalc.org

DarkerLine · Post by **DarkerLine** » Wed 16 Nov, 2005 11:34 pm

ticalc.org basic programs have never impressed me with their quality. Without downloading it, my guess is that either not all puzzles are solvable (have only one solution) or are too easy.

threefingeredguy · Post by **threefingeredguy** » Thu 17 Nov, 2005 12:46 am

I love sudokus. They run them in my newspaper and a few weeks ago I cut one out and ran off a few copies for my friends. Collectively by showing them to our friends we got half of my school hooked, you can't look around without seeing a sudoku puzzle. Its pretty cool because theres 2200+ students at my school. We could use a Sudoku game.

katmaster · Post by **katmaster** » Fri 18 Nov, 2005 3:36 am

wow, i was going to post an idea on this like 2 weeks ago and forgot. I say GO FOR IT!!!!! (I loves them too

)

Post by **Kozak** » Fri 18 Nov, 2005 8:38 am

Sudoku! Never thought about making that. They appear all the time here in newspapers....it's a real hit

. For an unpracticed mind like mine it's quite hard to solve one:).

Liazon · Post by **Liazon** » Mon 28 Nov, 2005 2:57 am

Is it possible for me to use a seed Sudoku?

like

Code: Select all

SudokuSeed:
 .db 1,2,3,4,5,6,7,8,9
 .db
 .db
 .db
 .db
 .db
 .db
 .db
 .db

Then I randomly switch rows and columns or rotate the entire sudoku.
Then I randomly select numbers that are displayed in the puzzle.

Will this work?

DarkerLine · Post by **DarkerLine** » Mon 28 Nov, 2005 3:05 am

Switching rows or columns does not preserve the 3x3 square property, so, no it won't work.

Liazon · Post by **Liazon** » Mon 28 Nov, 2005 3:15 am

only if you switch within the between rows 1-3, 4-6, and 7-9. Same with the columns. Switching 1 and 9, yeah, that'd cause problems.

Rotating the entire board seems like an interesting property. It completely preserves a valid solution. And, it seems to me, that you can't really tell the difference.

DarkerLine · Post by **DarkerLine** » Mon 28 Nov, 2005 10:03 pm

Some other transformations:

switching all occurrences of X to Y and vice versa.

subtract every number from 10 and put the result in its spot.

flip across a row, column, or diagonal.

You have to start with a valid sudoku though.

kalan_vod · Post by **kalan_vod** » Mon 28 Nov, 2005 11:18 pm

I don't know if this works, but if it does then just backtrack how he has it programed and then you should have the routine to figure out the solution.