Divide and Conquer - LMI January Monthly Puzzle Test - 15th to 20th January 2021
@ 2021-01-11 1:49 AM (#28786) (#28786) Top

Administrator



20001000500202020
Country : India

Administrator posted @ 2021-01-11 1:49 AM

Instruction Booklet


The IB is available now at the contest page.
The test starts on 15th January 2021.

@ 2021-01-11 4:03 AM (#28787 - in reply to #28786) (#28787) Top

craigkasper



Posts: 5

Country : Canada

craigkasper posted @ 2021-01-11 4:03 AM

In the instruction book, I would personally interpret the arrows in the Heterocut example to point from a larger region to a smaller region, while the rules state that "Arrows always point from a smaller to a larger region."

I'm not sure if that's in issue with me, or with the instruction book/example.
@ 2021-01-11 7:21 PM (#28793 - in reply to #28786) (#28793) Top

auroux



Posts: 145
1002020
Country : France

auroux posted @ 2021-01-11 7:21 PM

I was about to protest the notation for Heterocut, to point out that the arrows look a lot like "greater than" symbols in eg Futoshiki, and that it would be much more logical to have them point from larger regions to smaller ones, rather than from smaller ones to larger ones.
And then I found that the IB also got it wrong, suggesting that the proposed notation is so confusing that even the author may have had trouble sticking with it.

Since the IB will need revision about this: may I suggest that the IB example's notation is much better than the IB text's proposal, and that it would be even better if instead of arrows one had "greater than" symbols?
@ 2021-01-11 7:26 PM (#28794 - in reply to #28786) (#28794) Top

auroux



Posts: 145
1002020
Country : France

auroux posted @ 2021-01-11 7:26 PM

Also, still on Heterocut, unless I am mistaken the IB example (with notation of the example rather than of the text) seems to have multiple solutions. The I and L tetraminoes at the top can be replaced by L (at top-left) and O (at top-right), while replacing the trimino-domino-O tetromino in the bottom two rows by I tetramino at bottom-left corner, domino horizontally on top of it, L trimino in bottom right corner.
@ 2021-01-11 8:26 PM (#28795 - in reply to #28786) (#28795) Top

muhorka



Posts: 13

Country : Slovakia

muhorka posted @ 2021-01-11 8:26 PM

Yeah, you are totally right, the notation used in puzzle and in rules differs. The correct one is used in puzzle, so the rules will be changed to "Greater than symbols always point from a larger to a smaller region."

And yes, there is mistake in the puzzle, it has multiple solution. The example will be fixed.
@ 2021-01-12 3:19 AM (#28797 - in reply to #28786) (#28797) Top

IHNN




Posts: 21
20
Country : United States

IHNN posted @ 2021-01-12 3:19 AM

For the slitherlink regions, do the colored cells have to be inside a loop? Or is it possible to have the region be an outside area?
@ 2021-01-12 3:29 AM (#28798 - in reply to #28797) (#28798) Top

muhorka



Posts: 13

Country : Slovakia

muhorka posted @ 2021-01-12 3:29 AM

IHNN - 2021-01-12 12:19 AM

For the slitherlink regions, do the colored cells have to be inside a loop? Or is it possible to have the region be an outside area?


The colored cells have to be inside a loop.
@ 2021-01-12 8:56 AM (#28800 - in reply to #28786) (#28800) Top

auroux



Posts: 145
1002020
Country : France

auroux posted @ 2021-01-12 8:56 AM

Thanks a lot for the clarification! I must say I'm pretty excited about the concept of this round -- the IB example was already a lot of fun to solve! Though I will probably do badly, I tend to panic in rounds with heavily linked multiple puzzles, and region division puzzles aren't my strong suit.
Denis
@ 2021-01-14 4:06 PM (#28805 - in reply to #28786) (#28805) Top

Administrator



20001000500202020
Country : India

Administrator posted @ 2021-01-14 4:06 PM

Updated Instruction Booklet


An updated version of the IB is was uploaded at 4 PM on 14th January at the contest page.

Changes:
(1) Test duration is now 150 minutes.
(2) Heterocut rules and examples modified
(3) Instant Grading section in page 2 is updated. Each puzzle will be worth 100 points, and there will be penalties for wrong submissions.

@ 2021-01-14 4:08 PM (#28806 - in reply to #28786) (#28806) Top

Administrator



20001000500202020
Country : India

Administrator posted @ 2021-01-14 4:08 PM

Bonus points


6 points per minute saved, if all 10 puzzles are correctly solved.

@ 2021-01-14 4:28 PM (#28807 - in reply to #28786) (#28807) Top

Administrator



20001000500202020
Country : India

Administrator posted @ 2021-01-14 4:28 PM

Puzzle Booklet - Notes


1. Puzzle booklet will not contain any rules, examples, points details or answer key descriptions. It will only contain the puzzle name and puzzle grids.
2. There will be two version of the puzzle booklet - one in A4 and the other in A3 size.

@ 2021-01-14 6:29 PM (#28808 - in reply to #28786) (#28808) Top

rob



Posts: 170
100202020
Country : Germany

rob posted @ 2021-01-14 6:29 PM

This looks super fun, really enjoyed the example.

Question about the booklet: I imagine A3 would be a single page while A4 splits the puzzle across two pages at a similar resolution?

Also some formatting wishes (it will work fine as is, but if you happen to address this, lovely):
- the grid lines are very thick/opaque, making it hard to recognize a wall drawn over it; thinner dashing would be great
- I can make out the difference between blue and red on a grayscale print-out, but they're pretty close; I think if blue were made a bit lighter it would still be recognizable easily and the difference would be more clear
@ 2021-01-14 7:38 PM (#28812 - in reply to #28808) (#28812) Top

muhorka



Posts: 13

Country : Slovakia

muhorka posted @ 2021-01-14 7:38 PM

rob - 2021-01-14 3:29 PM

Question about the booklet: I imagine A3 would be a single page while A4 splits the puzzle across two pages at a similar resolution?


A3 is single page and A4 is 5 pages with same resolution of puzzles (2 puzzles for 1 page)

rob - 2021-01-14 3:29 PM

- the grid lines are very thick/opaque, making it hard to recognize a wall drawn over it; thinner dashing would be great
- I can make out the difference between blue and red on a grayscale print-out, but they're pretty close; I think if blue were made a bit lighter it would still be recognizable easily and the difference would be more clear


About thick lines, do you mean boundary lines? Because all other lines inside puzzle are dashed for that reason. I print it several times with different resolution, and everytime the lines was good. The coloring was my issue from the beggining, if use, and in what form,
but I should stick with this version. The actual puzzle will look pretty "similar" so, I belive, that it will be clear.
@ 2021-01-14 8:58 PM (#28813 - in reply to #28812) (#28813) Top

Administrator



20001000500202020
Country : India

Administrator posted @ 2021-01-14 8:58 PM

Answer Key


Reminder for Answer Key entry: If a cell contains a multidigit number, only enter the last digit for that cell.

@ 2021-01-14 10:08 PM (#28816 - in reply to #28812) (#28816) Top

rob



Posts: 170
100202020
Country : Germany

rob posted @ 2021-01-14 10:08 PM

muhorka - 2021-01-14 7:38 PM
About thick lines, do you mean boundary lines? Because all other lines inside puzzle are dashed for that reason. I print it several times with different resolution, and everytime the lines was good. The coloring was my issue from the beggining, if use, and in what form,
but I should stick with this version. The actual puzzle will look pretty "similar" so, I belive, that it will be clear.


No, I meant the dashed lines. They're quite dark and thick compared to usual puzzle renderings, so I find myself having to work my pencil hard to see a clear difference between "unused line" and "used line".

(I zoomed in on the booklet earlier and now understand a bit better for why they look the way they do. That's a very creative solution for making dashed lines :p, and I understand how it's difficult to change.)

Anyway, as I said I'll manage, and I promise I'll stop bugging you about that now. :p
@ 2021-01-14 11:12 PM (#28817 - in reply to #28816) (#28817) Top

Administrator



20001000500202020
Country : India

Administrator posted @ 2021-01-14 11:12 PM

Puzzle Booklet


The password protected Puzzle Booklet is now available for download at the contest page.

@ 2021-01-15 2:04 AM (#28819 - in reply to #28786) (#28819) Top

rob



Posts: 170
100202020
Country : Germany

rob posted @ 2021-01-15 2:04 AM

That was great, thank you so much for the contest!

I had my expected couple of hang-ups, worst the one where I was convinced the Slitherlink couldn't be unique in the top right corner. Then later I made quite a big mess of the bottom left corner of the Suguru, reliably running into contradictions with the Star Battle below and even starting to doubt the rules (should I be allowed to swap the two regions??). Finally once these were fixed, I started to feel sure I was on the correct path and things fell a bit faster with some more intuitive solving.

I'm not so sure what to think about instant grading for this kind of round. It's quite a help to have your partial solution confirmed correct. I think that encourages less rigorous solving because you run less risk of guessing yourself into a corner where you don't know how far you have to backtrack.
@ 2021-01-15 5:08 AM (#28820 - in reply to #28786) (#28820) Top

EctoPlasma




Posts: 23
20
Country : Japan

EctoPlasma posted @ 2021-01-15 5:08 AM

A great contest! Shame that I wrecked the solve.

I thought the gradual grading made the solve immensely less stressful and is generally a great thing to have. However, 90-70-40 penalty system may allow solvers to do thing like checking all possibilities for Spiral Galaxies without caring about the coloured regions. (I accidentally did this, mistakenly assuming that Spiral Galaxies was unique without influence from the other grids)

forcolin already pointed out that reloading resets the timer. When I also accidentally reloaded, I noticed the "Password for Puzzle Booklet" changed to 1351634143 (first answer key to Tripod Sudoku). It seems reloading while running the contest causes much trouble.
@ 2021-01-15 9:29 PM (#28822 - in reply to #28786) (#28822) Top

swaroop2011




Posts: 668
500100202020
Country : India

swaroop2011 posted @ 2021-01-15 9:29 PM

Claim - I think I entered Spiral Galaxies Solution correctly. Can you please check? Thanks.

Edited by swaroop2011 2021-01-15 9:31 PM
@ 2021-01-15 10:48 PM (#28823 - in reply to #28822) (#28823) Top

swaroop2011




Posts: 668
500100202020
Country : India

swaroop2011 posted @ 2021-01-15 10:48 PM

swaroop2011 - 2021-01-15 9:29 PM

Claim - I think I entered Spiral Galaxies Solution correctly. Can you please check? Thanks.


Edit - Muhorka pointed out that it's my mistake, I tried entering that solution in the Fillomino answer key :(
Can I still request to claim?
Thanks.
@ 2021-01-18 1:27 PM (#28837 - in reply to #28786) (#28837) Top

Kithyane



Posts: 49
2020
Country : France

Kithyane posted @ 2021-01-18 1:27 PM

That was an awesome puzzle to solve, I had a lot of fun ^^
Congratulation to the author for such a great creation :)
@ 2021-01-19 6:59 PM (#28838 - in reply to #28786) (#28838) Top

tamz29



Posts: 225
10010020
Country : Thailand

tamz29 posted @ 2021-01-19 6:59 PM

What a fun contest.
Brilliant idea for a big puzzle - but I do feel the answer keys and the instant grading format allows guess-and-check over solving logically.
A wrong assumption in Slitherlink ruined the last stretch for me and I couldn't finish in time.
I knew Yagit was my weakest puzzle going in, so it was not surprising that Yagit and the two bordering puzzles were ones I had left.
Thanks for the puzzle!