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motris
motris
25 April 2009 @ 12:21 pm
A fitting sudoku?  
So, here is the Guinness puzzle - Scanraid assures me, as I felt, that it is not-sledgehammer solvable, or reasonable to do in a fast time without bifurcation (guessing). Do it in under 10x the 3:06 time without guessing (let alone the 10 minutes round time) and I'll be amazingly impressed. If anyone ever asks why I hate sudoku competitions but like puzzles, this is a good example. I feel puzzles should be human-solvable, fun, and certainly in a competition serve a purpose of choosing the best, not the luckiest. Sudoku are too easily both computer-generated and made ridiculous, at least in a competition sense, and I've unfortunately stopped bothering to try to always solve logically because I know the rest of the world, in catching up to me, took up bifurcation. This "puzzle" should soundly prove the flaws of "fiendish" puzzles at a sudoku championship if the community of solvers didn't see them before now.

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[info]byronosaurusrex on April 25th, 2009 09:36 pm (UTC)
It's been 20 minutes since I started the sudoku....

And I have a grand total of one logically-placed digit.

This is a bifurcator's sudoku; decisively not a competition-caliber puzzle, and not something I would set my watch by, let alone a world record.

(Please delete the previous comment if possible; I posted anonymously by accident.)
.the .greg[info]lardarsegreg on April 26th, 2009 12:16 am (UTC)
Sad thing is, I think I know which digit it is...

I forget exactly what it means to be sledgehammer solvable. I know what it's referring to, but I guess I don't understand how its methods translate to "moves" that I would understand normally.
motris[info]motris on April 26th, 2009 06:21 am (UTC)
I can't say this definitely but generally sledgehammer complete includes an X-wing but not a Y-wing so you can sort of draw the dividing line on Scanraid steps at that point. This goes well below that line and scores a "record" 614 or so for a truly Diabolical Scanraid grade.
.the .greg[info]lardarsegreg on April 26th, 2009 06:59 am (UTC)
I so wish I followed sudoku enough to know all of the jargon.

Also: Am I the only person who thinks of Peter Gabriel when the sledgehammer solver is mentioned?
Adam R. Wood[info]zotmeister on April 29th, 2009 09:27 pm (UTC)
"Also: Am I the only person who thinks of Peter Gabriel when the sledgehammer solver is mentioned?"

No. - ZM
lunchboy[info]lunchboy on April 26th, 2009 02:20 pm (UTC)
This is a seriously un-fun sudoku.
motris[info]motris on April 26th, 2009 02:47 pm (UTC)
The new terminology is "sudoku". If even the organizers cannot be put in a room for 1 day to prove the uniqueness of the answer without computers, it is an epic fail.
zundevil[info]zundevil on April 28th, 2009 04:36 am (UTC)
Can we use a term like "quadrifurcation" for this? I don't even think a single guess will get you anywhere -- it probably branches out a few times.

I was going to ask the guy how he solved it so quickly, but I think I knew his answer already...
(Anonymous) on April 28th, 2009 05:04 pm (UTC)
Hmmm clearly the fitting thing to do here is to use the template, make sure that each number is used 3 times as a given, and make it as easy as posible so that this record has a chance of being discreditted.

Although not taking anything away from the belgian chappy. His final standing proves he was a very strong solver, and even making a guess there finishing solving in just over 3 minutes is still stunningly good.

Tom.C
(Anonymous) on April 30th, 2009 04:13 pm (UTC)
Only one guess required
After placing the 1 in R9C2, Vincent Bertrand may have noted that R9C5 could only be 3/7 and R7C5 could only be 3/8. Guess 3 in R9C5 and there is a complete logical path to the solution.

This has been bugging me since the championship. I didn't believe that Vincent would have made a cluster of guesses and now I am fairly certain he only needed to make one. There may well be other places in the grid where a single guess breaks the puzzle.

That said, I think everyone would prefer World Championship puzzles which could be solved logically.

David McNeill.
motris[info]motris on April 30th, 2009 04:16 pm (UTC)
Re: Only one guess required
Thanks for this observation. I focused my attention on Box 4 in the championship, and no 1 guess was to be found there. Computer graders could certainly be tweaked to check for these bifurcation "backdoors" but still, there MUST be a logical route that can be seen in the same amount of time.
(Anonymous) on May 1st, 2009 04:02 pm (UTC)
I know Vincent, he's a very strong sudoku player. Perhaps a future world champion. He's a very fast player and he improved a lot with variants this year !

Fred76