Logic Masters Deutschland e.V.

Chaos Skyscrapers

(Published on 17. December 2021, 03:37 by JoWovrin)

Finally managed to make a chaos construction puzzle! I have been trying to make one for a while, but I just couldn't come up with a fun clue type until now. Hopefully you enjoy!

-) Irregular Sudoku rules apply (place the digits 1-9 once each in ever row/column/region), the solver must devide the grid into regions consisting of 9 orthogonally connected cells.

-) Every cell contains a building with the height of its digit, taller buildings hide smaller ones behind them

-) Clues outside the grid are "chaos skyscrapers". They give the amount of buildings seen in their row/column, from their perspective. Additionally, all cells up until and including the highest building (9) from their perspective are in the same region, and if there is a cell directly behind that building (9) it must be in a different region. (all of the above is what makes up a "chaos skyscraper") The "?" can be any number.

-) All "chaos skyscrapers" are given. (Negative constraint)

Example 6x6 (highest building is 6) puzzle (play on penpa +)

This is the main puzzle. Solve online with penpa + (only checks for digits)

Solution code: Row 6 (left to right) + column 9 (top down), 18 digits, no other characters

Last changed on on 17. December 2021, 20:10

Solved by Steven R, marcmees, polar, Mark Sweep, tallcat, henrypijames, SSG, Gnosis66, pandiani42, abed hawila, SuWi, AnnaTh, OGRussHood, cdwg2000, Mody, peacherwu2, misko, ahmadasiabi, Uhu, pkp
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Comments

on 30. July 2022, 20:50 by peacherwu2
Impossible!

Last changed on 6. March 2022, 12:50

on 13. February 2022, 23:32 by SuWi
Irgendwie bin ich immer noch etwas unsicher, ob ich die Regel mit den negativen Bedingungen richtig verstanden habe.
Ist es so, dass eine Zahlenfolge, die am Rand beginnt und die sich bis zur 9 in der selben Region befindet, zwingend ein "chaos skyscraper" ist? Und damit auch zwingend nach der 9 die Region begrenzt sein muss UND sich am Rand ein Hinweis befinden muss?
Das ganze gilt dann aber nicht für die einfachste dieser Zahlenfolgen, die nur aus einer 9 am Rand besteht? Dort müsste doch sonst eine 1 am Rand stehen und eben auch die Region nach der 9 enden?
Oder ist es so, dass, wenn nach der 9 die Region noch nicht endet, das einfach nur kein "chaos skyscraper" ist, und es dann eben keinen Hinweis am Rand geben kann?

(reply) Entschuldige die späte Antwort, deine letzte Annahme ist richtig. Wenn a) die Region bereits vor der 9 endet, oder b) die Region nach der 9 noch weitergeht, handelt es sich NICHT um eine Chaos Skyscraper, und demnach kann auch keine Zahl in dieser Reihe/Spalte stehen. Die negative Bedingung bedeutet, dass wenn KEINE Zahl außerhalb der Reihe/Spalte steht, in dieser Reihe/Spalte a) oder b) zutreffen muss (es darf sich nicht um einen Chaos Skyscraper handeln), das gilt auch dann, wenn die 9 gleich am Anfang der Zahlenfolge steht.

(re-reply) Vielen Dank! Für die Antwort und das schöne Rätsel! Nachdem nun der Regelknoten in meinem Kopf gelöst war, konnte ich auch das Rätsel lösen.

on 4. February 2022, 16:55 by abed hawila
That was a rewarding ride! Excellent puzzle!

Last changed on 17. December 2021, 20:12

on 17. December 2021, 20:10 by JoWovrin
Clarified that the region restrictions are part of the chaos skyscraper to clear up confusion with the negative constraint.

Last changed on 18. December 2021, 07:12

on 17. December 2021, 19:17 by henrypijames
The rules are unclear about how the negative constraint applies: Is a 159 sequence from the edge without a 3 clue generally not allowed, or is it allowed if the three cells don't belong to the same region, or if they do belong to the region along with the fourth cell?

In other words, is "Additionally, all cells up until ..." part of the definition of "Chaos Skyscraper" - in which case they'd fall under the negative constraint - or is it an "additional" observation *about* the Chaos Skyscrapers - in which case the negative constraint doesn't cover it?

(reply) Sorry for the confusion! A Chaos Skyscraper always has the region building property, so that IS relevant for the negative constraint. So an unclued row/column can (and will in fact) have a standard skyscraper clue, it just can't also have the region properties of a chaos skyscraper.

If you have a suggestion for better wording I'm happy to change it!

<<< The confusion is mostly my own fault. Still, I think the rules could be clearer if they separate "chaos" from "skyscraper" - the two really don't have much to do with each other anyway. Like this:

A "chaos clue" is a clue outside the grid that indicates, in the corresponding row or column, starting from the clue, the first border between regions is located immediately behind the digit 9.

All given skyscraper clues are chaos clues, and all chaos clues are given (negative constraint).

Last changed on 17. December 2021, 19:08

on 17. December 2021, 18:09 by Mark Sweep
Wow, that was quite a workout. Definitely a 5 star puzzle indeed. There was awesome logic involved though!

(reply) Glad you enjoyed the logic! I had a lot of fun setting it :D

Last changed on 19. December 2021, 20:26

on 17. December 2021, 10:50 by henrypijames
LOL, the two-word title of this puzzle is a total nerd-trap for me - must try it now.

(reply) I really enjoy both variants as well ^^

<<< And wow, that's quite a journey. The "second part" is really hard to figure out. 5 stars difficulty for me as well.

(reply) Well done for getting through it, I hope you enjoyed the journey :D

Difficulty:5
Rating:97 %
Solved:20 times
Observed:4 times
ID:0008K0

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