Cave Sudoku
(Eingestellt am 10. Juli 2020, 12:39 Uhr von Phistomefel)
Es gelten die üblichen Sudoku-Regeln. Zudem müssen einige der Zellen grau gefärbt werden, sodass alle Graufelder (die Wände) orthogonal mit dem Rand verbunden sind und alle übrigen Zellen ein orthogonal zusammenhängendes Gebiet (die Höhle) bilden.
Jede gelb markierte Zelle liegt im Inneren der Höhle und die Ziffer darin gibt an, wie viele zur Höhle gehörende Felder in waagrechter und senkrechter Richtung gesehen werden können. Dabei wird das Hinweisfeld selbst mitgezählt und Wände behindern die Sicht. Die Ziffer in einigen der Hinweisfelder ist dabei zunächst noch zu bestimmen und nicht jedes mögliche Hinweisfeld ist angegeben.
In einem orthogonal zusammenhängenden Gebiet von Graufeldern dürfen sich dabei keine Ziffern wiederholen. Es können 2x2-Blöcke sowohl von Graufeldern als auch von nicht-grauen Feldern vorkommen.
Hier ist zur Illustration ein Beispiel auf einem 6x6-Gitter.
Hier noch ein kleiner Hinweis, der mir sehr geholfen hat, die Basislogik für Höhlenrätsel zu verstehen:
Es ist in jedem Höhlenrätsel möglich, einen Rundweg um die Höhle (die nicht grau gefärbten Zellen) zu zeichnen. Das hilft dabei, einige Konstellationen von vornherein auszuschließen.
Nun aber zum tatsächlichen Rätsel. Das gibt es auch online über f-puzzles und Penpa-Edit. Viel Spaß beim Lösen!
Lösungscode: 1. und 7. Zeile
Kommentare
am 11. Oktober 2023, 10:53 Uhr von Piatato
Lovely puzzle! Here's a new penpa link: https://tinyurl.com/2x3red4t
am 17. September 2023, 08:48 Uhr von CrazyCrypticC
Fascinating and wonderful logic.
am 5. November 2022, 14:43 Uhr von KNT
Awesome, thanks phisto :)
am 9. November 2021, 18:08 Uhr von dissonance
Very nice puzzle, thanks for sharing.
am 21. August 2021, 18:46 Uhr von Phistomefel
Added tag "Online solving tool".
am 21. Mai 2021, 16:13 Uhr von Vebby
Great puzzle! I found it easier to solve upon replacing the yellow colour with one-cell cages to indicate line-of-sight restriction, so that I could shade all cave cells one colour. Link to solve on Penpa Plus with this change: https://git.io/JsM36
am 30. Januar 2021, 17:41 Uhr von wydadman
رائع يا فيستوميفيل!
am 5. August 2020, 16:32 Uhr von glum_hippo
Die Regeln bedürfen m.E. keiner weiteren Erläuterung... sie sind nur deswegen leicht zu missverstehen, weil da so viel los ist! Aber wer Höhlenrätsel gemacht hat, wird irgendwann den Leitfaden finden (inkl. ffricke, der sich ja sehr gut auskennt)
am 5. August 2020, 16:02 Uhr von Phistomefel
@Nylimb: Thank you for the nice feedback and the perseverance!
@ffricke: Dankeschön! Die Regeln für das Rätsel sind auch ein wenig überbordend, da kann das leicht passieren. Im Nachhinein bin ich auch nicht mehr so glücklich mit der Unterscheidung zwischen Wandzellen, Höhlenzellen mit Hinweisen und Höhlenzellen ohne Hinweise.
am 5. August 2020, 09:56 Uhr von ffricke
Wundeschönes Rätsel, ich bin zunächst nur daran gescheitert, weil ich die Regeln nicht richtig gelesen habe.
am 25. Juli 2020, 17:49 Uhr von Nylimb
I had to start over about 3 times, because I'd made errors that led to contradictions. It was very satisfying to finally finish it without an error. Thanks for a great puzzle!
am 13. Juli 2020, 15:24 Uhr von henrypijames
@MartinR: You can simply use different colors. I used blue for clues (overrode yellow becaus blue is more visible) and green for non-clue cave, as well as red for walls.
am 12. Juli 2020, 18:33 Uhr von Circleconstant314
I'm so glad that the English description was simply missing the rule about walls needing to contain distinct digits. I was worried that this would be the first puzzle of yours that required heavy bifurcation but that rule clarification really smoothed out the solve. What a brilliant idea for a Sudoku, thanks for sharing this one! :-)
am 12. Juli 2020, 17:01 Uhr von MartinR
Wonderful puzzle.
Thanks to @Narayana for that video link, that was really helpful as had not come across cave logic before.
One minor comment - when solving I found it hard to keep track of the inner clues as if I marked all the inner cells in one colour the highlights disappeared and having two colours for the same area (inner) didn't make the border between outer/inner as distinctive for me
This might be just me, but for my use I created an alternative penpa link where the inner clues were circled and unaffected by shading which I found clearer - for me at least:) - as could use one inner colour and not lose the clue locations. If interested, link is https://tinyurl.com/y44sahzv
am 12. Juli 2020, 09:11 Uhr von Phistomefel
Clarified rule.
am 12. Juli 2020, 09:05 Uhr von Phistomefel
Thank you all for the wonderful feedback and apologies for leaving you with an unsolvable puzzle by forgetting to add the no-repetition rule in the english description. I guess in the future I should leave a puzzle unpublished for a day or so and then proofread it once more before I activate it.
am 12. Juli 2020, 07:51 Uhr von Mody
Großartig :)
am 11. Juli 2020, 18:36 Uhr von Madmahogany
Another great one!
am 11. Juli 2020, 18:35 Uhr von glum_hippo
Nervenaufreibend, aber das ist keine Kritik! Wunderbare Idee
am 11. Juli 2020, 14:59 Uhr von henrypijames
Wonder how long it takes for this one to get onto CTC. My bet: within a week.
am 11. Juli 2020, 14:43 Uhr von anu_chakravarti
Totally missed the walls having unique numbers rule and kept staring at the puzzle for way too long. Nevertheless absolutely delightful puzzle!
am 11. Juli 2020, 12:43 Uhr von Jesper
I did wonder yesterday at why the small example did not seem to have a unique solution. But unfortunately, I shrugged it off, and tried to solve the puzzle, oblivious to the missing restriction. It was a lot more fun today, having found out about that restriction. Great puzzle!
am 11. Juli 2020, 11:57 Uhr von henrypijames
Oh wow, that is a huge additional restriction, as it dramatically limit the length of any wall right away.
Guess I should make it a habit to always read both the English and the German descriptions every time. There have been discrepancies in a number of puzzles here (most deadly, the solution code on one occasion).
am 11. Juli 2020, 11:18 Uhr von marcmees
got stuck in a dark cave until the additional rule gave some extra light. nice concept. thanks
am 11. Juli 2020, 07:10 Uhr von Phistomefel
@cdwg2000: Thanks a lot for your questions! I simply forgot to add the no-digit-repetition rule in the english description. I am very sorry for that!
am 11. Juli 2020, 07:09 Uhr von Phistomefel
Missing rule added in english description.
am 11. Juli 2020, 06:49 Uhr von r45
Tolles Rätsel!
am 11. Juli 2020, 03:14 Uhr von cdwg2000
The rule description should be added: in the gray area connected orthogonally, the numbers cannot be repeated.
am 10. Juli 2020, 21:27 Uhr von Narayana
@Big Tiger
What you describe is what Simon (CTC) calls "Checkerboard Logic." This pure cave video https://www.youtube.com/watch?v=Jjs_xA1sDCg was very helpful to understand how Cave works.
am 10. Juli 2020, 18:54 Uhr von Big Tiger
Can two open spaces or walls touch each other diagonally? For example, could you have Wall in R3-C3 and R4-C4, with open spaces in R3-C4 and R4-C3?
EDIT: Hmm, I THINK I just answered my own question in further experimenting, but your answer will help clarify...
@Big Tiger: This diagonal constellation is indeed impossible. And I found it easier to spot this knowing that there has to exist a path around a cave (then two pieces of the path would touch each other diagonally which is impossible).
*** Welll, that's what I thought, which is why I'm stumped. I'm creating a short video to explain my perplexity better than I could in text. I'd love to know where either I'm misunderstanding something or my logic is failing me. As soon as it's posted I'll link you to it.
am 10. Juli 2020, 18:17 Uhr von GuessIt
Do not click "solve" on f-puzzles once you're finished. You will regret it. I certainly do. (It messes with all the digits somehow and removes everything else, including coloring)
am 10. Juli 2020, 16:00 Uhr von Phistomefel
@henrypijames: Yes, that is right, an uncolored given digit can be anything. The walls can also contain 2x2 blocks. Now, I see that I could have chosen a better example. Thanks!
am 10. Juli 2020, 14:51 Uhr von henrypijames
An uncolored given digit can be either wall, non-clue cave, or (possible) clue cave?
And the wall doesn't have to be one cell wide, meaning it can contain 2×2 blocks?
