Funny.

Is this possible that if I put all the numbers outside the grid (which indicate the number of shaded cells) it may lead to multiple solutions? [For Town puzzle or any of this kind of puzzle]

Congratulations for the contest !!

Puzzle 9:
I don't understand very well: "At the same time,starting from theb lack circle, draw a loop along the lines of the grid,passing through all rows and columns."
Can someone explain that to me in more detail?

Thanks.

Ok, I have seen that it can be solved without understanding it very well...

Thanks kiwijam for summarizing rules, but I don't agree with the interpretation of the rule 11. I agree with athin, the Diamonds rule set includes the border rule.
It becomes a problem in the following case.

(use 2,3,4 cards)
~~~~~~~
D~D~D~~
~~~~~~~
~~~~~~~
~~~~~~~
~~D~~~D
~~~~~~~
~~D~~~D
The position of the card 2 is unique or not?

I imagine each participant has different interpretations. It's a pity that the winner will change depending on the Riad's final judge after the contest....
I hope Riad will answer that question as soon as possible not to ruin this wonderful contest.

Edited by panista 2020-04-16 4:55 PM

yes

I see a unique position for 2. This is a card with diamonds P2C3 and P6C3. What other options are possible?

Oh dear. My interpretation was wrong then, that I posted a day ago.
According to my understanding of the rules, this diagram fails the sentence "All transparent cards from 2 to 4 are put on the table so that it is possible to uniquely restore their contours".
Because there are three places the 2-card might fit.
This is the opposite approach to puzzle 10, where the extra rule (no white 2x2) applies to the unique solution, not to the solving process.
Unfortunately it is 1:30am here, and I don't have time to start again...

We can extend the competition for a day.
I want to say about the puzzle 10. Its text changed the day before the start. My friends from India didn't like my translation using a translator. There was a misunderstanding. As a result, the text has changed a lot.

My text using the translator looked like this:
Place dark rectangles in the 12 x 10 grid, the lengths of the sides of which are at least 2 cells. They do not touch each other, not even diagonally. The number outside the grid shows the number of dark cells in the corresponding row. The puzzle must have a unique solution in your placement of the numbers. In this case, the white cells must form streets with a width of one cell, i.e. the white area of the streets cannot contain fragments of 2 x 2 cells. Maximize the number of streets. Among solutions with equal result the best will be the one in which the sum of the given numbers is less.

Why is this discussion still happening? I thought it was "no more ambiguous" or even unambiguous from the beginning and I was posting countless questions forn nothing.



I thought kiwijam cannot be wrong ;)

Edited by anurag 2020-04-16 7:31 PM

Riad, the translation from your original text sounds much better than what the admins reduced it to. Not surprising, given that "You must submit before ..." has been there for years now in bold font on the submission pages.

Anurag, the second version also appeared through my efforts. We were looking for a more understandable wording, but as time has shown, we have not clarified the issue. I am very grateful to the administrators for their work. They have supported me for many years. Please note that the entire serious workload of the organizers is based on enthusiasm.

Oh... I have just decided to read discussion thread and here is my opinion. Please be consequent. As long as "borders of cards cannot have common segments" is a part of Diamonds puzzle rules, the same should be in operation for "the white are of the streets cannot contain fragments of 2x2 cells" for a Town puzzle. Why should I assume two different interpretation for two puzzles? As the Diamond puzle doesn't make a sense without this rule, I obviously assumed as well that "the white are of the streets cannot contain fragments of 2x2 cells" is the rule of the Town Puzzle. I will be very unsatisfied if you don't consider this interpretation because I spent literally 30 hours (!) optimising the Town puzzle. I have not only found a good solution but I have also proved mathematically that my solution is the best possible. It needed both using some mathematical tools and checking hundreds of cases what I did patiently. I am not going to spend further time to optimise the Town puzzle without that rule. Please consider it when making decision about this puzzle. As I said I would be very unsatisfied if my work went for nothing.

Whatever you decide, big appreciation for Riad for the next very good contest.

If I may suggest something for next editions, maybe the better idea is to publish optimization puzzles in the format below.

Town puzzle rules.
Place some dark rectangles, that are at least two cells wide and two cells high. They cannot touch each other, not even diagonally. The numbers outside the grid show the number of dark cells in the corresponding row or column. The white cells must form streets – the any stretches with a width of one cell and length at least two. The white area of the streets cannot contain fragments of 2x2 cells.

Make a Town puzzle with a unique solution in the 12x10 grid. Maximize N, thenumber of streets. If two solutions have the same N, then the solution with the smaller sum of the given numbers is considered better.

or

Town puzzle rules.
Place some dark rectangles, that are at least two cells wide and two cells high. They cannot touch each other, not even diagonally. The numbers outside the grid show the number of dark cells in the corresponding row or column.

Make a Town puzzle with a unique solution in the 12x10 grid. This unique solution must meet the condition "The white cells must form streets – the any stretches with a width of one cell and length at least two. The white area of the streets cannot contain fragments of 2x2 cells." Maximize N, thenumber of streets. If two solutions have the same N, then the solution with the smaller sum of the given numbers is considered better.

And everything would be clear :)

Edited by lukasz6500 2020-04-17 12:34 AM

So...uh...it's still not clear to me on puzzle 10. Should I make clues as if deductions utilizing "no 2x2 [or bigger] white squares" are allowed? Or do I need to clue it so that all dark squares are hit by a clue?

If I were a decision maker, I would accept both interpretations (making two separate rankings for both cases) or I would cancel the whole puzzle at all. But I am not.

I have not been on the forum for quite some time and I now notice the discussion has become very messy. I can't understand why. To me the rules of the diamonds and of the battleship were clear. Cards cannot have common segments and (after Anurag's question) can touch at corners. OK where is the problem? Obviously in the example given by panista I can see only one way of placing the card 2 without overlapping of any of the segments. any alternative way of placing the card would cause partial overlapping of contour segments. During the course of the competition I generated some solutions which I discarded because I could swap the position of the cards 2 and 3 so I did not have a unique solution.For puzzle 10 I needed to ask a question to Riad and after his reply everything was clear: my understanding was (and still is ) that I have to solve a "Clouds-like" puzzle avoiding 2x2 white areas, and that I could not use the extra rule of the absence of 2x2 white areas to exclude some combinations. Perhaps not everybody has read Riad's comment on my question (do players read answers to questions asked by other players?) or not everybody understood my question because i did not post a diagram with it, however subsequently there was a question about why there is the digit 2 in the example and that clarified the matter further (and I believe completely). I recommend to Timjamiller to go back at page 2 of the comments and to read Riad's answer to my question and to the question asked by panista related to the example. To me arguments such as "if in puzzle 10 a certain rule xxxx is applied in a certain way then in puzzle 11 we should adopt the same interpretation" are not sustainable. every puzzle is a puzzle in itself and it can well be that rules can be different for different puzzles.

I did not read discussion thread before today. I totally agree with you that your question resolves doubts about rules of Problem #10. But I didn't read it before. I just explained why I had interpreted rules in another way (another argument is that in previous editions such sentences like absence of 2x2 white areas applied for puzzle rules) and that I spent plenty of time solving this puzzle in that way. And by the way, the contents is still unclear and not updated in puzzle booklet.

For me, in that case, both or any approaches should be taken into consideration. Extending time is also a valid solution, but in that case, please clarify the contents in puzzle booklet and give enough time (e.g. until the end of this week) to make a proper approach.

if the contest has been extended it seems that nobody told the clock. new answers are not accepted

Fixed.

I am waiting for the official decision of organisers. For me, accepting only one approach, without clarifying contents of puzzle booklet and extending contest for more time, is unaccaptable. But it is just my opinion :) Above is my explanation. I have already told everything and I am just waiting for the official decision.

Some serious lessons for the admins in the last few posts.

Stefano, that reply from Riad, as I had mentioned several times, was grammatically incorrect. And that was the source of all confusion. It is a shame that nobody answered that question of mine, even yet. I also prepared a very specific question on that reply. If you read all my posts, which I don't think others did, you should notice that I also said that the puzzle, as I understand, was trivial. This was enough clue that my understanding was incorrect (same as what one of the users posting today thinks). Nobody corrected me on that. Some think and claim everything was crystal clear, pretend to help with some forced answers, report weird statistics like how many posts I made, and yet speculations do not end. Endorsing can be fun, but one should not sound like a sponsor.

Edited by anurag 2020-04-17 11:00 AM