2014 WPF Puzzle Grand Prix

Information and discussion on Puzzle Competitions
dickoon
Posts: 615
Joined: Mon 21 Jun, 2010 12:52 pm
Location: Stockton-on-Tees, UK
Contact:

2014 WPF Puzzle Grand Prix

Post by dickoon » Fri 31 Jan, 2014 7:40 pm

The WPF are holding a puzzle Grand Prix with some degree of similarity to the sudoku one. The six rounds take place at weekends, with each fortnight alternating between a puzzle GP and a sudoku GP.

The first puzzle round, constructed by Germany, takes place this weekend; the window to complete the 90-minute paper runs from 10am UK time today until 10pm UK on Monday February 3rd.

Download the instruction booklet from here. Looks like 12 puzzles of mostly fairly familiar types, but based on the Sudoku GP first round, I would expect them to be pretty meaty, and the Germans have always written interesting puzzles.

You can register if you haven't done so yet; I'd guess that registering for the Sudoku GP probably gets you into the Puzzle GP as well. More information at the WPF GP web site.

dickoon
Posts: 615
Joined: Mon 21 Jun, 2010 12:52 pm
Location: Stockton-on-Tees, UK
Contact:

Re: 2014 WPF Puzzle Grand Prix

Post by dickoon » Tue 04 Feb, 2014 12:04 am

(Preliminary?) results have been automatically posted online at the conclusion of the contest. Fast work, WPF! The first round proved as meaty a challenge as expected, with the median solver solving possibly four or so of the twelve puzzles. Fewer than ten solvers managed to crack all twelve in the time, with Hideaki Jo the fastest. (Bram de Laat was nearly ten minutes faster still - which is, perhaps, the equivalent of winning a 100m sprint by a clear second - but a stutter on puzzle twelve proved decisive.)

375 solvers were placed as a result of answering at least one puzzle correctly (I imagine there may well also have been scores of participants who failed to, er, score) and 37 countries were represented. The UK had 16 scorers on the board, putting us in eighth place in terms of participation. Congratulations to James for topping the UK section of the leaderboard, with a world-class top-twenty performance overall, and to Neil, Tom and the other participants. Thanks to the WPF for the infrastructure and the German puzzle devisors.

(The UK round is going to have slightly more of the relatively accessible puzzles... isn't it? ;) )

PuzzleScot
Site Admin
Posts: 2737
Joined: Fri 18 Jun, 2010 10:45 pm
Location: Edinburgh, Scotland

Re: 2014 WPF Puzzle Grand Prix

Post by PuzzleScot » Tue 04 Feb, 2014 9:16 am

Hmm. A tough one for openers! (I have no excuses for my dismal display).

Great to see so many names from the UK.
I hope none of the new British players are put off by their first contest being so challenging. Stick at it folks - that's about as hard as it gets! Honestly!

Magoo
Posts: 89
Joined: Thu 09 Jun, 2011 1:22 pm

Re: 2014 WPF Puzzle Grand Prix

Post by Magoo » Tue 04 Feb, 2014 12:29 pm

Hats off to James especially.

I'm massively relieved to hear this was particularly hard, as, even though I was interrupted and had to stop just after an hour, I had assumed that my 2-puzzle performance was beyond dismal. Perhaps I'll take courage and try again next time, rather than just assume it was all down to unfamiliarity with the puzzle types (and being dumb).

kiwijam
Posts: 698
Joined: Wed 01 Jun, 2011 10:03 am

Re: 2014 WPF Puzzle Grand Prix

Post by kiwijam » Wed 05 Feb, 2014 4:55 am

Thanks all. I spent the day in bed with flu so not ideal conditions.
The test was definitely hard though, which normally suits me. The types were generally well known, but most of the puzzles had me guessing with a pencil. Especially "No 4 In A Row", where I had no better idea than just trying and retrying different options. There may be some advanced logic to be learnt there? (although I did find a triangle of three pairs above the centre that gives a quick cell to enter)

Another tip: The Pentominoes puzzles is easier if you first sum up the left and top clue numbers, which will tell you the number of cells used in the central row and column.

Hausigel
Posts: 94
Joined: Sat 13 Nov, 2010 3:07 pm

Re: 2014 WPF Puzzle Grand Prix

Post by Hausigel » Wed 05 Feb, 2014 11:16 am

Hi there,
I worked hard to make sure that the "No Four in a Row" puzzle wasn't just an exercise in searching for three identical symbols in a row. Many puzzles of this type include only this kind of step; let us call it a "one-stage" reasoning. The intended solving path for the contest puzzle contains "two-stage" solving steps like the following one on at least three occasions:

----
xo--
x-o-
-xx-

If you put an X in the bottom-left cell of this 4x4 block, it forces two O's in opposite corners which will produce a diagonal row of four O's. A very similar pattern (probably the one James is mentioning) is actually the starting point for the solution. But such triangular constellations can occur in various shapes, and one that is much harder to spot lies in the columns 8/9.
Hausigel

kiwijam
Posts: 698
Joined: Wed 01 Jun, 2011 10:03 am

Re: 2014 WPF Puzzle Grand Prix

Post by kiwijam » Mon 10 Feb, 2014 10:54 pm

Hi Roland,

Thanks for your post. You're right, most "No Four in a Row" puzzles only use first-order logic. At the recent WPC there were 5 of these in a team round, graded by difficulty, and even the harder ones still only used it. It makes the puzzles less challenging, and more a visual puzzle like "can you find three symbols and one blank in a row" again and again.
But this puzzle was worth more points than usual, unfortunately I was lazy and ignored the warning! If anyone is curious, I will explain more about this second-order logic.
PRIME_BBCODE_SPOILER_SHOW PRIME_BBCODE_SPOILER:
Basically the idea is that you look for three straight segments of length 4, that intersect each other in a triangle shape. The 3 intersection cells are all empty, the remaining 6 cells are all filled in with three pairs of two symbols along the three straight segments. One symbol (X) will appear on two lines, the other symbol (O) on one line.
There are 4 possible triangle shapes. Roland shows the simplest, (1) a large triangle with sides of length 4:

Code: Select all

.
AB
A B
.BB. 
(2) There is also the medium triangle with sides of length 3:

Code: Select all

B
.
BA
.B.B
   A
or other variations of this like:

Code: Select all

.
BB
.A.A
B  B
 
(3) A small triangle with sides of length 2:

Code: Select all

B
.
..BB
B A
   A
(4) Or a triangle with two diagonal sides:

Code: Select all

B  B
. B
B.
. A
   A
These are just examples of the sort of configurations to look for.
In every case above, the cell where the two B-lines cross cannot be a B also, so it must be an A.

In the GP contest puzzle, there are two of these triangles to find in the starting grid, and I used two more as I was solving, but I'm pleased to say the whole puzzle is logically solvable and is a nice introduction to this second-order logic. Thanks Roland!

PS Anyone know a better way than "

Code: Select all

" to write fixed-width characters here?[/spoiler]
Last edited by kiwijam on Tue 25 Mar, 2014 3:17 am, edited 1 time in total.

emma
Posts: 314
Joined: Wed 22 Jun, 2011 4:58 pm

Re: 2014 WPF Puzzle Grand Prix

Post by emma » Wed 12 Feb, 2014 10:08 pm

Nice - I spotted the case of (1), but I hadn't thought through the other possibilities.

PuzzleScot
Site Admin
Posts: 2737
Joined: Fri 18 Jun, 2010 10:45 pm
Location: Edinburgh, Scotland

Re: 2014 WPF Puzzle Grand Prix

Post by PuzzleScot » Wed 12 Feb, 2014 10:27 pm

kiwijam wrote:PS Anyone know a better way than "

Code: Select all

" to write fixed-width characters here?[/quote]
[strike]I'm afraid that's the only way at the moment...[/strike]
I'm sure I could add options to allow font selection, but the last thing I want is 40px red font [i]anywhere[/i] near here...

[edit:] This seems to work. Test text follows, using 'fixed-width' tags, (looks pretty-ish Problem is that multiple spaces collapse to a single)
[fixed-width]. B B .  .  .
. A . B . .
. . A B . .
. . . . . .[/fixed-width]

Trying 'pre' as a tag: (not bad. Only thing I notice is that leading spaces are lost.)
[pre]. B B .
  A   B
    A B
      .[/pre]
So how's that? Select text required as monospace, and click the 'pre' formatting button.

kiwijam
Posts: 698
Joined: Wed 01 Jun, 2011 10:03 am

Re: 2014 WPF Puzzle Grand Prix

Post by kiwijam » Fri 14 Feb, 2014 1:21 am

Agreed, looks like
 is the best of the options. Thanks Alan.

sknight
Posts: 141
Joined: Mon 01 Nov, 2010 8:46 pm

Re: 2014 WPF Puzzle Grand Prix

Post by sknight » Mon 24 Feb, 2014 11:02 pm

The Slovakian round is coming up this weekend.
The IB is up.
As with the sudoku competition the other week, it doesn't
look like we're getting reminder emails.

dickoon
Posts: 615
Joined: Mon 21 Jun, 2010 12:52 pm
Location: Stockton-on-Tees, UK
Contact:

Re: 2014 WPF Puzzle Grand Prix

Post by dickoon » Sat 01 Mar, 2014 7:42 am

The Slovakian round is now in progress. Good luck, all!

dickoon
Posts: 615
Joined: Mon 21 Jun, 2010 12:52 pm
Location: Stockton-on-Tees, UK
Contact:

Re: 2014 WPF Puzzle Grand Prix

Post by dickoon » Tue 04 Mar, 2014 1:19 am

Results were posted automatically again and... wow. Second place of 291 scorers for Neil, fifteenth for James! World class, gents, with a rush of UK names (Steve, Alan, Tom, Emma and Mark) all well in the top third. Congratulations all round!

Seventeen UK solvers this time, one up from the first round, so the UK moves up from eighth to seventh in terms of participation. Some UK names I'm less familiar with on the scoreboard, too, which is always good to see.

(I was delighted to solve five puzzles and thoroughly enjoyed the time I spent doing so. Unfortunately I did manage to misenter the Snake, despite solving it correctly. The roundabout to that particular swing is that I thought I had submitted the "Capsules" answer a few seconds too late, so perhaps there are scant seconds of grace period after all, explaining my 01:30:00 time.)

Magoo
Posts: 89
Joined: Thu 09 Jun, 2011 1:22 pm

Re: 2014 WPF Puzzle Grand Prix

Post by Magoo » Tue 04 Mar, 2014 9:13 am

Amazeballs, Neil! Look at the names he's taken out ... and consistent brilliance from James too. Well done, guys. I'm awestruck.

User avatar
furudo.erika
Posts: 76
Joined: Wed 10 Aug, 2011 11:55 am

Re: 2014 WPF Puzzle Grand Prix

Post by furudo.erika » Tue 04 Mar, 2014 12:36 pm

Really impressive UK showing, especially Neil.

I found the answer keys to be rather onerous. I'm not surprised I botched one also.

kiwijam
Posts: 698
Joined: Wed 01 Jun, 2011 10:03 am

Re: 2014 WPF Puzzle Grand Prix

Post by kiwijam » Wed 05 Mar, 2014 4:02 am

Well done Neil, looks like you had a great day.

I thought the theme was very well done. None of the puzzles (except the last) were very difficult, but the large sized grids just meant they were time-consuming.
The Snake had a poor answer key, considering better options were used for other puzzles.
And the Hitori answer key had a confusing and contradictory last sentence: ": For each column from left to right, enter the length in cells of the longest segment of unpainted cells... If there are no black cells in the row, enter a single digit ‘0’."
- if any columns had been all-white there would have been some chaos there!

sknight
Posts: 141
Joined: Mon 01 Nov, 2010 8:46 pm

Re: 2014 WPF Puzzle Grand Prix

Post by sknight » Wed 05 Mar, 2014 3:49 pm

I'm pretty sure I'm just terrible at entering the codes for some of these contests.
I only had credit for 6/8 puzzles, and I'm pretty sure it was just the answer key.
It would help if they had the little "correct/incorrect" feedback you get on many LMI contests,
but also the keys were sort of a pain on this one.

I did really enjoy the puzzles. I was sort of hoping we'd see walkthroughs of some
of them done in terms of actual Slovakian Geography. "The break-in point is near
the border with Ukraine, and continues south and west along the border with Hungary..."

dickoon
Posts: 615
Joined: Mon 21 Jun, 2010 12:52 pm
Location: Stockton-on-Tees, UK
Contact:

Re: 2014 WPF Puzzle Grand Prix

Post by dickoon » Wed 05 Mar, 2014 4:32 pm

Ha! I did not even realise, until you intimated it, that the shape of all the grids was, to a first approximation, the shape of the outline of Slovakia. How cute!

Nilz
Posts: 266
Joined: Fri 02 Sep, 2011 5:21 pm

Re: 2014 WPF Puzzle Grand Prix

Post by Nilz » Wed 05 Mar, 2014 6:27 pm

Very surprised, but delighted, to be that high. I found most puzzles quite easy, and assumed a lot more people would finish. They were nice puzzles though; the shape of the grid I guess constrained the compilers quite heavily, which meant I found it relatively easy to find a logical path through most puzzles, which is always nice! Had a bit of luck too- I put a few shapes in the LITSO, expecting to have to tweak a fair bit, but it worked straight away. I'm amazed that solution was unique. And I'm a bit surprised I didn't mess up any answer keys, which were a bit weird, as others have said. But it's the same for everyone, and they were published in advance.
Good to see quite a high level of UK participation too, and some high placings to go with it.

kiwijam
Posts: 698
Joined: Wed 01 Jun, 2011 10:03 am

Re: 2014 WPF Puzzle Grand Prix

Post by kiwijam » Tue 25 Mar, 2014 3:23 am

So, it must be time for Round 3 of the Puzzle Grand Prix.

The instruction book has been released: http://gp.worldpuzzle.org/content/instruction-booklet-2

The competition will be this weekend, March 28-31.

Round 3 is written by a large Japanese team, consisting of 20 puzzles.
The first 17 are 'common' types, with 3 variants at the end: Afternoon Skyscrapers, Count Number, and Box of 2 or 3. (I'm curious if anyone has seen any of these 3 previously?)

sknight
Posts: 141
Joined: Mon 01 Nov, 2010 8:46 pm

Re: 2014 WPF Puzzle Grand Prix

Post by sknight » Wed 26 Mar, 2014 10:52 pm

kiwijam wrote:So, it must be time for Round 3 of the Puzzle Grand Prix.

The first 17 are 'common' types, with 3 variants at the end: Afternoon Skyscrapers, Count Number, and Box of 2 or 3. (I'm curious if anyone has seen any of these 3 previously?)
They're unfamiliar to me, although I'm not the most experienced puzzler out there. Still, it surprised me to see a Skyscrapers variant that 1) looked very interesting and 2) hadn't been used on the Skyscraper variant contests at LMD.
I'm still thinking about the tricks for logically cracking the Box thing (the others made good sense and I've got a rough feel for them).

PuzzleScot
Site Admin
Posts: 2737
Joined: Fri 18 Jun, 2010 10:45 pm
Location: Edinburgh, Scotland

Re: 2014 WPF Puzzle Grand Prix

Post by PuzzleScot » Thu 27 Mar, 2014 12:03 pm

kiwijam wrote: Afternoon Skyscrapers
From memory - Wasn't there something like this in Kraljevica?

emma
Posts: 314
Joined: Wed 22 Jun, 2011 4:58 pm

Re: 2014 WPF Puzzle Grand Prix

Post by emma » Thu 27 Mar, 2014 7:31 pm

Similar, but I'm not sure it was quite the same. I think we had numbers round the edge as normal, but the count was the number of skyscrapers you could see if you looked down at a 45 degree angle, rather than parallel to the ground. I think that means the main difference is that you didn't know which of the blocks behind a tall one were in shadow.

kiwijam
Posts: 698
Joined: Wed 01 Jun, 2011 10:03 am

Re: 2014 WPF Puzzle Grand Prix

Post by kiwijam » Thu 27 Mar, 2014 10:23 pm

Ah thanks, I've found Afternoon Skyscrapers in Round 13 of Eger 2011, same puzzle but different presentation style.

dickoon
Posts: 615
Joined: Mon 21 Jun, 2010 12:52 pm
Location: Stockton-on-Tees, UK
Contact:

Re: 2014 WPF Puzzle Grand Prix

Post by dickoon » Wed 02 Apr, 2014 11:59 am

Round three results are up! Glorious reading for UK eyes, with two solvers in the top six out of 287 on the board, just a point apart from each other. I'll leave it to you to guess who they are... and who pipped whom to fifth place. :D Many congratulations to you both!

I will say that the "Country", "Points" and "Time" links on that page don't work properly - they will resort the round 2 results, not the round 3 ones, by the order you pick. Instead, open the full results and sort that way. Looks like there were ten UK solvers this time ((ETA: which puts us down from seventh to eighth equal)); down on last time, but there was the small matter of the UK Open tournaments on the same weekend keeping people busy! (I'm curious to know whether people who doubled up did the GP before the UK Open or afterwards...)

As a discussion point, my teeny tiny claim to fame is that I was the only UK solver out of the ten to get puzzle 2a. It was my favourite of the whole contest, but I definitely think you could argue that it had no place being there, as it's not language-neutral. (True, it was only worth 8 points out of a possible 609, but it's still an eyebrow-raiser.) That may be the only clue you need. It runs, roughly: "What comes next in this series? 1, 4, 3, 11, 15, 13, 17, 24, ?"

Many thanks to the Japanese authors for another very enjoyable contest and to the WPF for making it all happen, time after time!
Last edited by dickoon on Wed 02 Apr, 2014 12:35 pm, edited 1 time in total.

Post Reply