Sudoku

[somersetchris]

Su Doku's successor is now here - much harder apparently although I haven't yet sat down to try it in the office.

The Times who started the Su Doku thread in the UK have now brought overSamunamupure or Killer Su Doku (there are several on the linked page)
The wrinkle is that there are now dotted lines selecting groups of cells which have a small number in them. The normal Su Doku rules apply with the added challenge that now the numbers within each dotted line have to add up to the smaller number alongside and you get no numbers to start the usual process. Looking forward to trying it...

If you do get stuck with killer, can I suggest you go to this link http://www.ndorward.com/blog/?page_id=50 After I saw this I was able to do them in half of the time. This guy has some very good tips on solving them.

BTW, does anyone still have the ones (or a link to them) that they used for entry to the Times championships? What was to stop someone entering the numbers into one of the various available freeware programs and getting them solved by computer?

 

[Doctor Q]

I saw the Top Ten list for best-selling non-fiction paperbacks this week. Four of them are Sudoku related (#2, #6, #9, and #10)!

 

[IJ Reilly]

If you do get stuck with killer, can I suggest you go to this link http://www.ndorward.com/blog/?page_id=50 After I saw this I was able to do them in half of the time. This guy has some very good tips on solving them.

I've been working these puzzles for a couple of months now, and I have to admit I don't follow much of anything this person is saying. For one thing, the terminology he uses is completely unfamiliar to me.

 

[Veldek]

I'm developing a Cocoa app to help design the puzzles manually, cause it can be quite difficult...

A German math professor did write an app to solve each Sudoku puzzle. I don't remember which algorithm he used though.

 

[aricher]

If you live in the UK, you may have seen Newsnight - Sudoku is apparantly takking our newspapers by storm. Here is a nice little freeware Sudoku program for OS X: (scroll down)
http://www.educationaltechnology.ca/dan/

Maybe The Brit Twit Phil Collins could change his lyrics and re-issue his old classic Sussudio Dunno - that's the first thing that comes to mind when I see the name of the game.

 

[IJ Reilly]

A German math professor did write an app to solve each Sudoku puzzle. I don't remember which algorithm he used though.

I can't imagine how this would be useful, if only because any Sudoku can be solved if in no other way than by brute force. The solution to any given puzzle is not interesting. How you get there is the intriguing part. A program to solve Sudoku would be kind of like a chess program that solves chess problems by saying "checkmate" without showing the moves that get you there.

 

[Veldek]

I can't imagine how this would be useful, if only because any Sudoku can be solved if in no other way than by brute force. The solution to any given puzzle is not interesting. How you get there is the intriguing part. A program to solve Sudoku would be kind of like a chess program that solves chess problems by saying "checkmate" without showing the moves that get you there.

Well, I think it's the fact that he found an algorithm to solve Sudoku puzzles which is the most interesting part here. I agree that the journey is the reward, but it's interesting that he found a mathematical way to solve these puzzles. It's kind of solving Sudoku in a more abstract kind of way. For mathematicians, this is great fun

 

[Doctor Q]

I can't imagine how this would be useful, if only because any Sudoku can be solved if in no other way than by brute force. The solution to any given puzzle is not interesting. How you get there is the intriguing part. A program to solve Sudoku would be kind of like a chess program that solves chess problems by saying "checkmate" without showing the moves that get you there.

That's a very good point. I tease gamers who are delighted to find cheat codes for video games so they can bypass levels. What if they found a cheat code that let them go from the start screen to the final winner's screen, bypassing the game entirely? Would they be happy with that too?

There are lots of Sudoku-solving programs now, and it might be fun to write one of them, but I wouldn't want to use one.

 

[IJ Reilly]

I can understand using cheat codes in video games once in a while -- after all they aren't necessarily constructed like puzzles and the solutions are often illogical (e.g, "gamey"). IOW, you can't always "figure out" how to get to the next level, sometimes you just need to get lucky. But a Sudoku puzzle should never require luck to solve, though I'm pretty sure I've encountered a couple at least that didn't have a logical solution method. I don't know enough about the construction of the puzzles to know whether they can be made "broken," but it seems like they can.

 

[maka]

In the context of hand-making the puzzles, good solving algorithms (not brute force) are useful to make sure the puzzle has one solution (and only one).

There are some puzzles that "require" guessing to solve, but these are not considered "real" sudoku. So a brute force solving program is not really very useful...

 

[camomac]

under-a-rock

wow i never even heard about this... i feel so left-out...
i can't wait to get home from work and start playing around
with some of these.

 

[IJ Reilly]

In the context of hand-making the puzzles, good solving algorithms (not brute force) are useful to make sure the puzzle has one solution (and only one).

There are some puzzles that "require" guessing to solve, but these are not considered "real" sudoku. So a brute force solving program is not really very useful...

A brute force method is, I believe, the only method that would work for solving a puzzle which has no logical solution. Guessing would be required. A brute force program would essentially be computer-assisted guessing on a massive scale.

 

[Doctor Q]

Doing the daily puzzles in the newspaper, I had my best-ever and worst-ever performances this week. I did yesterday's in under 5 minutes but one earlier in the week took me over an hour. I don't know why it took me so long, and I was grumbling and muttering to myself about low long it was taking as I worked on it. Still, I enjoyed doing both of them!

 

[Doctor Q]

Newsweek had an article about Sudoku but spelled it Su Doku. Are there mixed opinions about whether it is one word or two?

 

[Applespider]

Newsweek had an article about Sudoku but spelled it Su Doku. Are there mixed opinions about whether it is one word or two?

In the UK, it's usually two words. The Times, who claim credit for its introduction, call it Su Doku. Course, they've now moved onto Killer Su Doku.
Try one - I've attached it alongside (the tricky one to make it more interesting for you Dr Q!)

Samunamupure (it translates as “sum number place” and we have named it Killer Su Doku) is a variation that has been evolving among Nishio and his small clan of devoted puzzle students for some years. It is, he says, the perfect example of a next-generation puzzle: it is simple to understand, requires no insider knowledge or training and rewards pure and simple logic.

The digits within the oddly shaped “inner boxes” (marked by dotted lines) must add up to the small number written in the top corner of that box. Apart from that, all the normal Su Doku rules apply. “The really satisfying part,” says Nishio with an evil smirk, “is that you can design a Samunamupure puzzle in a way that you do not need to insert any starting numbers in the grid. I think that will make some people very disturbed.”

 

[AP_piano295]

anybody know where I can download these? they havent shown up in my papers yet

 

[Savage Henry]

I've never quite sunk enough commitment to get into it; it just doesn't get me going. I've tried the books, tried the papers, tried the widget, but I just can't sense the buzz even slightly reaching me. Praps I need to spend more time on trains. I'll probably start to get interested when it becomes unpopular and the new fad becomes the ancient art of walnut gargling .... or something.

But it is really interesting to see the people who it has gripped; quite a few people from many many backgrounds.

 

[IJ Reilly]

anybody know where I can download these? they havent shown up in my papers yet

Get your daily Sudoku fix here:

http://www.sudoku.org.uk/daily.asp

 

[IJ Reilly]

I've never quite sunk enough commitment to get into it; it just doesn't get me going. I've tried the books, tried the papers, tried the widget, but I just can't sense the buzz even slightly reaching me. Praps I need to spend more time on trains. I'll probably start to get interested when it becomes unpopular and the new fad becomes the ancient art of walnut gargling .... or something.

But it is really interesting to see the people who it has gripped; quite a few people from many many backgrounds.

I don't think I've become a Sudoku addict exactly, but I do like to work them over lunch. Gives me a half hour or so to divert my mind from more important matters. Just a mild distraction that's active, instead of passive, like watching TV.

Walnut gargling? Hmmmm.

 

[Doctor Q]

If the people who have written programs to generate the puzzles and the people who have written programs to solve the puzzles would simply connect their programs together, we could have an application that generates puzzles, solves them, and then erases all traces of these actions. That would let people solve the maximum number of puzzles per hour while saving the earth by keeping the environment free from puzzle debris, and it would save us all a lot of puzzle-solving time and trouble!

But that idea is just for the people who find Sudokus frustrating. My best relaxation time each day is when I do the daily puzzle (by hand).

 

[IJ Reilly]

If the people who have written programs to generate the puzzles and the people who have written programs to solve the puzzles would simply connect their programs together, we could have an application that generates puzzles, solves them, and then erases all traces of these actions. That would let people solve the maximum number of puzzles per hour while saving the earth by keeping the environment free from puzzle debris, and it would save us all a lot of puzzle-solving time and trouble!

But that idea is just for the people who find Sudokus frustrating. My best relaxation time each day is when I do the daily puzzle (by hand).

Kind of like folding for Sudoku? Great idea! I wonder how long it would take for all the possible puzzles to be created and solved. Then we could all get on with our lives, knowing that Sudoku had been cured once and for all!

BTW, is the correct plural "Sudokus" or "Sudokui?" Inquiring minds, and all that...

 

[Savage Henry]

Walnut gargling? Hmmmm.

Don't knock it ... I've been practising for the last 3 days just to get ahead of the pack ... you'll be doing it soon ... you'll see ...

I do like to work them over lunch. Gives me a half hour or so to divert my mind from more important matters.

Every lunch I get free I find I'm reading a good mentally heavy book to do the same, so perhaps you and I aren't so different after all ... perhaps one day I'll forget my book and stumble across a newspaper ... and from then on I'll be hooked

 

[Lau]

In the UK, it's usually two words. The Times, who claim credit for its introduction, call it Su Doku. Course, they've now moved onto Killer Su Doku.
Try one - I've attached it alongside (the tricky one to make it more interesting for you Dr Q!)

In reference to "Killer So Doku", "fiendish" crosswords and the like - the Hideous Portal Of Gael'thoth! (about halfway down)

 

[Doctor Q]

I got a bit (well, OK, a month) behind on daily newspapers while I was on vacation, but I saved all the sudoku puzzle pages from those papers and I've gradually been catching up by doing two "daily" puzzles per day. Twice the fun!

 

[IJ Reilly]

I got a bit (well, OK, a month) behind on daily newspapers while I was on vacation, but I saved all the sudoku puzzle pages from those papers and I've gradually been catching up by doing two "daily" puzzles per day. Twice the fun!

You are definitely obsessed.