Diogen IPST. 23-30 September 2011

[PuzzleScot]

Dear puzzle friends,

Septembers contest by Riad Khanmagomedov will start at September 23.
The contest will contain 12 puzzles, which you will have one week to solve.
The test file will be available at
http://diogen.h1.ru/cgi-bin/contest/contest.pl?id=43

Good luck!

Andrey Bogdanov

For newbies, this is a set of 12 (traditionally) very hard puzzles, including a couple of optimisers, with what appears to be no time limit. However, you will (almost certainly) find that one week is still not long enough to solve them all!
Some of the most beautiful puzzles I have ever seen have appeared in the Diogen quarterly puzzle contests.

Highly recommended!

[kiwijam]

Thanks for pointing this out, I downloaded the previous test for a look and am now eagerly awaiting the start of this one. A change of pace to the normal speed runs, and the puzzles are very good quality.

[PuzzleScot]

I didn't finish my last puzzle until this afternoon. Some really nice puzzles in there as usual. Thanks to Riad (and Andrey) for organising this

[PuzzleScot]

Provisional results are now up: http://diogen.h1.ru/cgi-bin/contest/result.pl?id=43

[detuned]

Wow, nice going guys, I make that 3 of us from the forums in the top 10!

[PuzzleScot]

Wow, nice going guys, I make that 3 of us from the forums in the top 10!

I prefer "2 of us in the top 4", or "3 in the top 7", but yeah, cool...

There were a couple of problems in the optimisers.
10. "There may be only one king in this part". This was meant to mean "If you only have one king in this part, that's not a problem".
12. Design a tapa - There is an inifinite solution, that James, Hideaki and myself spotted.

Still, great contest, with some very challenging puzzles. Most enjoyable!
#5 - Polymino is the stand-out puzzle, if you're just going to do one puzzle. (hint: do not attempt without a ruler!)

[AndreyBogdanov]

There were a couple of problems in the optimisers.

Riad worries about this very much. He cannot decide what to do with puzzle 10. The first variant is to consider results as final and the second is to give maximum points for the solutions with only one king and 52 cells.

[PuzzleScot]

There were a couple of problems in the optimisers.

Riad worries about this very much. He cannot decide what to do with puzzle 10.

Discussing with Stefano earlier, he suggested you separate the solutions into 2 groups:
- The ones that included both kings, and the ones with one king.
For EACH group, award the points as if the other group did not compete.
This seems reasonably fair, although I realise this will knock me down a few places.

[kiwijam]

Looks like there's been a rescoring of puzzle 10, which has bumped me up to the top. Very happy with the result, not necessarily so much with the actual process. And we still have 2 in the top 4 and 3 in the top 7.
The first 9 puzzles were great. Tough and innovative, and possible to work through over a week. Worth downloading definitely.

Then I was hoping for three good optimizers to sort out the field. Unfortunately they all had 'difficulties'.
Puzzle 10 had an ambiguous instruction, which meant Russian readers got higher scores than English readers. This has since been fixed, but I also wonder if too much chess knowledge is required for it.
Puzzle 11 annoyed me. You had to find as many distinct symbols as possible, in groups of 4. But I think the maximum number of symbols was 23, meaning finding 20 was easy, and most people did, but you could only get tantalizingly close to the next band of 24. So 'everyone' got full points and no spreading of the field occurred here.
And finally puzzle 12, which did not have enough restrictions. It was possible to get infinite solutions in different ways, using a mostly-full infinite 1xn strip, or a mostly-empty 10xn strip or an mxn 2D-grid. Maybe it needed a maximum size, like the previous competition had (an 8x8 maximum slitherlink). The puzzle writer adjusted the rules during the week to ban the mostly-empty solutions, but not the mostly-full one. So the top score was given to a mathematical curiosity, rather than to the puzzlers who genuinely constructed some good solutions. I was really worried how this might get treated, so I submitted my answers 4 days early to give me time to create a different solution if they didn't like it.

Anyway, can't wait til next time, hopefully these wrinkles will be ironed out.