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Riad Khanmagomedov's April Contest — 20th to 28th April 2016116 posts • Page 4 of 5 • 1 2 3 4 5
@ 2016-04-29 10:51 PM (#21613 - in reply to #21482) (#21613) Top

chaotic_iak




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chaotic_iak posted @ 2016-04-29 10:51 PM

So, feedback about the contest.

Not particularly enjoyable. This contest just reiterates the reason I dislike large puzzles. (Even though I authored NEW, HUGE, AND CHALLENGING! and one puzzle in Puzzle Marathon, yes.) The puzzles are so tough that you don't know where to look. While this is not a very big problem for the earlier puzzles (Pentobattle and the Clouds variant were nice), I particularly dislike Borderless Sextet and Crossmind. The former is probably because of the rules being terribly unclear, even after clarifications in-thread (where some went unanswered). The latter because it looks like pretty much all work, with no logic visible. I bruteforced the Mastermind puzzles by programming, and even after getting all possible answers for each, I couldn't even start putting any to the grid; too many letters that cross each other in all positions. And of course I loathe Accordances just like I loathe similar inductive puzzles. Yes, I got the expected answer for that, but I still dislike it anyway.

Puzzles that I solved, besides Accordances above... Pentobattle was a nice, easy puzzle. In Terms of Area, despite being big, is actually manageable, because that's approximately the size of medium-large Clouds puzzles. Both are my favorites for the contest. Coded Arrows wasn't very memorable; I think there were a few trial and error, testing whether a number works for a letter. Bricks was fine during solving, although it's a rather awful idea; I don't know why, I just don't like that genre in general. Probably because the positions of the clues are already given, so finding the sums can be independent from placing the bricks. I distinctly recall Trid-Fir requiring quite a lot of casework, putting a certain number here to find a contradiction about 10-20 numbers later. Mirrored Sudokus were actually quite fine; the large-scale logic of placing the 4s and the 3s early is interesting, although I think that's pretty common in Mirrored Sudokus in general. Opti-Pentobattle was a fun one. In The Citadels was just messy; the first thing I did was to convert it to a graph, then blindly trying things until I stumbled on a solution.

So, yes, I don't know why I keep doing these April Contests even though I don't particularly enjoy some of them. Maybe just because they are puzzle tests that are otherwise rare here on LMI nowadays.
@ 2016-04-30 3:43 AM (#21614 - in reply to #21482) (#21614) Top

forcolin




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forcolin posted @ 2016-04-30 3:43 AM

The feedback about the contest from me is the opposite... one of the best contests of the year.
People believe we are good because we solve difficult puzzle.
But what about those persons who SET the difficult puzzles? they are even more genial in my opinion.
I enjoy particularly this contest because traditionally I have my best results. A bit unconventional, speed does not count that much..... This contest is the Paris-Roubaix of puzzling. If it wasn't for a stupid typing mistake I could have been in the top five, in excellent company. Will try again next year.
These puzzles in general are very well constructed and with the right type of twist. The best for me was the borderless sextet, very deceptive with that double black cell on which I lost hours. Believe it or not, I started solving it from the Scrabble. Also very good the Voyage; I also liked the Coded Arrows for its simple and very logical solving path (couldn't see it, Chaotic?).The least beautiful the mirrored sudokus (ended up cross-eyed... you know, at my age......) and the Crossmind. And yes, I did not like too much Accordances, which requires more intuition than logic. The first optimizer, in the modified variant, has turned out to be very good, while the Citadel could have been a bit larger thus offering more possible options. As it has been pointed out before in the discussion, for both optimizers it was possible to demonstrate at a certain (early) stage that no better solutions were possible.
Thanks Riad for yet another very enjoyable week.
Stefano

Edited by forcolin 2016-04-30 3:48 AM
@ 2016-04-30 5:12 AM (#21615 - in reply to #21482) (#21615) Top

Para



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Para posted @ 2016-04-30 5:12 AM

The Crossmind puzzle was really enjoyable to me. I could get to all Mastermind puzzles logically, Even with the non-uniqueness. It helped me reinforce some of the logic involved as I hadn't really done many recently.
The secong part of the puzzle relied very much on uniqueness. Knowing that certain words had multiple solutions, they would have to go cross with other words to fix uniqueness. This actually made the Crossword very solvable. This might not be the favourite logic for many, but it's the kind of creative thinking that is expected in this contest. Think outside the box, find ways to approach the problem differently. That's what to expect in this contest.

The same could be said about the Bordeless Sextet. I actually constructed almost the whole crossword, except for LQQ on a separate piece of paper and then tried to fit it in. It's a bit like optimising. How can I use this space optimally, so that I expect everything to fit? You know in advance there's going to be relatively little space to use, so you start recognising how things fit together. It's not necessarily, "oh this 9 shape has to go there", but "oh this would be a perfect spot for this 9 shape; it is like it's made for it". It's good to train these skills too, to have a feeling what the author did, instead of what the author wants you to do.

That thinking also comes into place in the optimisers. First you figure out you need an even number of steps to get to 0, then you work out how to get this as high as possible. The highest possible Even Steps path doesn't have a 0 solution though. That took me a while to prove. So then lose 2 steps and try again.
The other optimiser turned from easy to, how do I get these 10 ships in as small a shape as possible. And then, which cells should remain blank to have a possibility to ever be unique. And then can I cover the rest with pentominos. With the last step being, make sure it's unique. This can be annoying.

I get that this contest isn't for everyone, which is why it gets these low competitor totals. But for those who enjoy it, they are always fun.
@ 2016-04-30 6:34 AM (#21616 - in reply to #21615) (#21616) Top

tamz29



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tamz29 posted @ 2016-04-30 6:34 AM

In general, I have the same mindset as Ivan (Chaotic). Large puzzles are boring (we're talking 25x25 sudoku "large" and not some other creative "large" eg. some of the puzzles in LMI marathon).
However, I will make the case for the Borderless Sextet and Voyages.
Who would think Borderless Sextet starts from the Scrabble? The weird letter patterns in the word list should prompt you create a draft of the grid - which only had about 3-4 possible alternatives and ruling out each one wasn't so guessy. Packing in numbers and tetrominoes were very logical. So I felt this puzzle required initial insight and mostly logic. Defitinitely not blind stumbling like the Crossmind (I don't think using uniqueness should be a job for solvers).

Voyages was also procedural. Start with the biggest piece and work your way from the maximum values 21-20-19-18-17.. Etc.
The solving path may have been a little too narrow that one mistake can ruin hours of work.
But the bottom line is you can see that it is logical.

@ 2016-04-30 9:25 AM (#21617 - in reply to #21482) (#21617) Top

chaotic_iak




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chaotic_iak posted @ 2016-04-30 9:25 AM

My complaint about Borderless Sextet is that I can't understand the instructions, so I didn't even attempt to solve it. For example, I've been understanding Loop that "touching" means Snake-like touching; if adjacent cells are both part of the loop, then the loop must also go through them consecutively. The regions are also said to be contiguous, so I wondered what could fit inside the hole that the Loop region had to make. (Although I haven't seen the solution, I'm pretty sure that the loop simply had to not cross each other, so the "touching" is Masyu-like touching; going in adjacent cells is okay.)

While that alone isn't a big complaint, my issue is that I asked for clarification, but it went unanswered. I believe rule questions should be answered, because otherwise it's an unfair disadvantage for people that interpreted the ambiguous instruction incorrectly (for having an immediate contradiction like above).

For Crossmind, the fact that you need to use uniqueness metalogic also means that it's a bad puzzle. If Riad created this puzzle by also using uniqueness, I wonder how many solutions were missed; if Riad created it purely with logic, I'm interested to know the intended path.
@ 2016-04-30 11:27 AM (#21618 - in reply to #21617) (#21618) Top

tamz29



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tamz29 posted @ 2016-04-30 11:27 AM

chaotic_iak - 2016-04-30 9:25 AM

My complaint about Borderless Sextet is that I can't understand the instructions, so I didn't even attempt to solve it.

For Crossmind, the fact that you need to use uniqueness metalogic also means that it's a bad puzzle. If Riad created this puzzle by also using uniqueness, I wonder how many solutions were missed; if Riad created it purely with logic, I'm interested to know the intended path.


I agree on both points. I also had to rereard the instructions several times over before solving. In the past (and this time) well-intentioned early finishers help answer questions in the forums. But surely, having a test solver reword some of the instructions beforehand would be quite productive.

Also eager to hear other people's experience with the Crossmind.

@ 2016-04-30 11:44 AM (#21619 - in reply to #21482) (#21619) Top

Kithyane



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Kithyane posted @ 2016-04-30 11:44 AM

Hi, just checked why I had no points for Borderless Sextet. For the first column, the offcial answer is FXLLDVD99LQQ--B-B and mine is FXLLDVD99LQQ--B-- (only difference is a ship or not in the last cell). In my grid, I have on the last row for battleship a BBB-B- pattern which could be switched to B-BBB- to get the official solution. Could it be that the aswer is not completely unique ? Or I have made an error elsewhere that I fail to see. Could someone enlighten me ?
http://i.imgur.com/WJqx96W.jpg
@ 2016-04-30 1:47 PM (#21621 - in reply to #21619) (#21621) Top

tamz29



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tamz29 posted @ 2016-04-30 1:47 PM

Kithyane - 2016-04-30 11:44 AM

Hi, just checked why I had no points for Borderless Sextet. For the first column, the offcial answer is FXLLDVD99LQQ--B-B and mine is FXLLDVD99LQQ--B-- (only difference is a ship or not in the last cell). In my grid, I have on the last row for battleship a BBB-B- pattern which could be switched to B-BBB- to get the official solution. Could it be that the aswer is not completely unique ? Or I have made an error elsewhere that I fail to see. Could someone enlighten me ?
http://i.imgur.com/WJqx96W.jpg


You missed ZY from Scrabble - that changes the Battleship regions.
@ 2016-04-30 2:41 PM (#21622 - in reply to #21482) (#21622) Top

Kithyane



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Kithyane posted @ 2016-04-30 2:41 PM

Arg, such a stupid error... thanks tamz29 !
@ 2016-04-30 6:33 PM (#21623 - in reply to #21617) (#21623) Top

Riad Khanmagomedov



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Riad Khanmagomedov posted @ 2016-04-30 6:33 PM

chaotic_iak - 2016-04-30 9:25 AM
While that alone isn't a big complaint, my issue is that I asked for clarification, but it went unanswered. I believe rule questions should be answered, because otherwise it's an unfair disadvantage for people that interpreted the ambiguous instruction incorrectly (for having an immediate contradiction like above).

Your questions, I gave a clear answer - the 16-length loop to be accommodated in the 16-cell region (see under your question).
@ 2016-04-30 6:40 PM (#21624 - in reply to #21617) (#21624) Top

Riad Khanmagomedov



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Riad Khanmagomedov posted @ 2016-04-30 6:40 PM

chaotic_iak - 2016-04-30 9:25 AM

My complaint about Borderless Sextet is that I can't understand the instructions, so I didn't even attempt to solve it. For example, I've been understanding Loop that "touching" means Snake-like touching; if adjacent cells are both part of the loop, then the loop must also go through them consecutively. The regions are also said to be contiguous, so I wondered what could fit inside the hole that the Loop region had to make. (Although I haven't seen the solution, I'm pretty sure that the loop simply had to not cross each other, so the "touching" is Masyu-like touching; going in adjacent cells is okay.)

While that alone isn't a big complaint, my issue is that I asked for clarification, but it went unanswered. I believe rule questions should be answered, because otherwise it's an unfair disadvantage for people that interpreted the ambiguous instruction incorrectly (for having an immediate contradiction like above).

For Crossmind, the fact that you need to use uniqueness metalogic also means that it's a bad puzzle. If Riad created this puzzle by also using uniqueness, I wonder how many solutions were missed; if Riad created it purely with logic, I'm interested to know the intended path.

The Contest must be surprised for solvers, otherwise it is not interesting for me, as for the author. 90-minute contests with a focus on well-known genres, with hundreds of fans, I am able to spend each week. Actually, I do it regularly for magazines published in Russia.
I can only say that I propose handmake puzzles. All of them are solved logically.
Ivan, you thought that the crossword grid can be constructed to eliminate the options? Do you think that I was not able to provide unique solutions for each Mastermind? The ambiguity of some Mastermind was intentional. You kidding me, it seems.

If you have any questions, I'll answer after 4 May.
@ 2016-04-30 7:19 PM (#21625 - in reply to #21618) (#21625) Top

prasanna16391



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prasanna16391 posted @ 2016-04-30 7:19 PM

tamz29 - 2016-04-30 11:27 AM


But surely, having a test solver reword some of the instructions beforehand would be quite productive.



I feel I should answer this since I've been test solving Riad's contests for the past few times.

All of these times, I have reworded the instructions. This time too, I reworded them for the ones I solved. Even some of the answer keys have been reworded and edited, both this time and in the past. For whatever reasons (time, capabilities, other commitments, etc.) I couldn't complete some of the puzzles, including Borderless Sextet. I tried them for a significant amount of time and couldn't do much. I'm just generally weak at word puzzles, so maybe that's part of the problem. Since there are so many variables in those rules I decided it best to leave them unchanged, since I might put in something wrong, having not solved it.

Its still true that I failed to do a complete job this time as the test solver, but I just wanted to share this because the suggestion made has already been implemented over the years, and this year too for some of the puzzles.

As for the contest itself, my thoughts are it is a special attraction contest which has its own unique value in the puzzle community. I think solvers should realize that sometimes a puzzle might have a logical path which is just beyond their prowess, as I found out with the Borderless Sextet's Scrabble start and the Crossmind's crossword part. If this happened in a 90 minute timed contest it is definitely up for debate whether the puzzle should have been on the contest or not. But as a special attraction contest making it clear at the outset that these are difficult puzzles without a time limit, I think its important to go in with a mindset that you may not be able to spot everything no matter how good a solver you are in other contests. Its just more space to improve, or an area to ignore, depending on individual perspective.
@ 2016-05-01 12:02 AM (#21626 - in reply to #21482) (#21626) Top

Riad Khanmagomedov



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Riad Khanmagomedov posted @ 2016-05-01 12:02 AM

Prasanna, thank you for your help in testing and translation of texts into English!
Before leaving, I found time on a detailed response about Crossmind.
I'll start with history. In Russia it is published a series of magazines "Handmade". They content are Keywords, Fillwords, Tetris and other word puzzles. From the first issues they published Crossmind’s invented by me. Typically several pages using words of different lengths.
Ivan, I advise you to make a Crossmind with 4-6 words, as in our magazines. When you feel the puzzle, then make more difficult tasks:
1. In each Mastermind given words should denote the same thing in different languages.
2. Crossmind should not be split into two independent puzzles – Mastermind and Crossword. Therefore, some Mastermind must be solved at the expense of crossword intersections. That is, it is necessary to construct a crossword grid, which guarantees uniqueness Crossmind.
3. Black crossword cells must draw the letters L, M, I.
I spent several days creating Crossmind. I was engulfed in a process so that refused lunch.
I will come back to the discussion on 4 May.
@ 2016-05-01 1:22 AM (#21627 - in reply to #21623) (#21627) Top

chaotic_iak




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chaotic_iak posted @ 2016-05-01 1:22 AM

Riad Khanmagomedov - 2016-04-30 9:33 PM

chaotic_iak - 2016-04-30 9:25 AM
While that alone isn't a big complaint, my issue is that I asked for clarification, but it went unanswered. I believe rule questions should be answered, because otherwise it's an unfair disadvantage for people that interpreted the ambiguous instruction incorrectly (for having an immediate contradiction like above).

Your questions, I gave a clear answer - the 16-length loop to be accommodated in the 16-cell region (see under your question).


The second part of the question was not answered, whether the loop may touch itself. I do know that the region is made of 16 cells, but I don't know how the loop works. My question was something like this. Left part is a correct Masyu-like loop, while right part is an incorrect Snake-like loop. Which of them is the rule in the puzzle?
@ 2016-05-01 1:25 AM (#21628 - in reply to #21482) (#21628) Top

chaotic_iak




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chaotic_iak posted @ 2016-05-01 1:25 AM

Re Crossmind: That's why I'm interested to know the intended logical path to solve Crossmind, because it just looks completely beyond any approach I can think of.
@ 2016-05-01 4:43 AM (#21629 - in reply to #21628) (#21629) Top

rob



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rob posted @ 2016-05-01 4:43 AM

chaotic_iak - 2016-05-01 1:25 AM

Re Crossmind: That's why I'm interested to know the intended logical path to solve Crossmind, because it just looks completely beyond any approach I can think of.


I would guess that you missed some of the Mastermind deductions. If my notes are correct, there are just 7 ambiguous words, of which only two have more than two options.
@ 2016-05-01 9:35 AM (#21630 - in reply to #21629) (#21630) Top

chaotic_iak




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chaotic_iak posted @ 2016-05-01 9:35 AM

No, I'm very confident my "solves" for Mastermind were right (because I just used programming to brute force each combination). But even with all of that, I still can't figure out where to start placing any of them.
@ 2016-05-01 3:43 PM (#21631 - in reply to #21482) (#21631) Top

dm_litv



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dm_litv posted @ 2016-05-01 3:43 PM

About the "Crossmind" discussion:
The crossword part of this puzzle is completely logically solvable without using of uniqueness.
You should start with second "left-to-right" word (middle top of the grid).
The first and the last letters of this word must be 4th letters in some pair of words.
There are only 3 possible words, 2 of them very quickly lead to the contradiction.
Next - everything goes without problems.

On the competition as a whole - it is exactly as it should be.


Edited by dm_litv 2016-05-01 3:46 PM
@ 2016-05-01 8:19 PM (#21633 - in reply to #21631) (#21633) Top

forcolin




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forcolin posted @ 2016-05-01 8:19 PM

dm_litv - 2016-05-01 3:43 PM

On the competition as a whole - it is exactly as it should be.


I fully agree.

[a bit OT, a question for admin] Is there scope for competitions dedicated to optimization puzzles only?

Stefano

Edited by forcolin 2016-05-01 8:19 PM
@ 2016-05-02 4:38 PM (#21634 - in reply to #21625) (#21634) Top

hsaa509



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hsaa509 posted @ 2016-05-02 4:38 PM

I am unable to understand about it, could you reply me with proper or actual question?
@ 2016-05-04 4:58 AM (#21638 - in reply to #21633) (#21638) Top

kiwijam



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kiwijam posted @ 2016-05-04 4:58 AM

forcolin - 2016-05-02 3:19 AM

Is there scope for competitions dedicated to optimization puzzles only?

Stefano


I think the optimization puzzles are the highlight of Riad's tests.
This time there were only 2, and they were 'solvable', but I'd like to see more too!
@ 2016-05-04 8:33 PM (#21641 - in reply to #21482) (#21641) Top

Riad Khanmagomedov



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Riad Khanmagomedov posted @ 2016-05-04 8:33 PM

Thanks to all the participants! Next year it will be necessary to return to the format with three optimization puzzles.
@ 2016-05-04 9:40 PM (#21642 - in reply to #21482) (#21642) Top

forcolin




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forcolin posted @ 2016-05-04 9:40 PM

I agree with both the last posts. However I miss a bit the good old DOM.
@ 2017-08-27 5:04 AM (#23059 - in reply to #21482) (#23059) Top

Eugene Porter



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Eugene Porter posted @ 2017-08-27 5:04 AM

Does anyone have a solution for the Trid-Fir? I keep getting stuck.
@ 2017-08-28 8:01 AM (#23060 - in reply to #23059) (#23060) Top

Eugene Porter



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Eugene Porter posted @ 2017-08-28 8:01 AM

This is a very tough contest. I am also struggling with the Voyage puzzle. Even after looking at the answer string I am not sure how to do this puzzle. Is there a solutions page somewhere. After spending several days on these and getting nowhere it would be nice to know what it is I am not getting. Any help would be great.
Riad Khanmagomedov's April Contest — 20th to 28th April 2016116 posts • Page 4 of 5 • 1 2 3 4 5
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