Logic Masters Deutschland e.V.

Colossal Cave Sudoku

(Published on 28. October 2022, 03:02 by tesseralis)

Inspired by Magnus Josefsson's Colossal Fillomino with Sandwich Sudoku, I thought about what other genres would make a good giant grid and settled on making a giant cave! Please enjoy.

Cave: Shade some cells in the 27×27 grid such that all unshaded cells are orthogonally connected to each other and all shaded cells are orthogonally connected to the edge of the grid. Clues are unshaded and indicate the number of unshaded cells seen in the four orthogonal directions, including itself. Shaded cells obstruct vision.

Sudoku: Fill in the 9×9 grid with the digit 1-9 such that each digit occurs exactly once in each row, column, and box. The digit in each cell in the sudoku grid corresponds with the number of unshaded cells in the corresponding 3×3 box in the cave grid.

Example:

Play the example puzzle on Penpa.

The puzzle:

Play on Penpa

(Unfortunately, there is no answer checking as it breaks Penpa's URL shortener.)

Solution code: length of all unshaded segments of the cave grid in rows 6, 7, 21, 22, from left to right. For example, in the example puzzle, rows 5 and 6 would be 114121.

Last changed on on 28. October 2022, 03:21

Solved by h5663454, cdwg2000, AstralSky, KNT, RJBlarmo, polar, henrypijames, Jesper, Mrtn, Jaych, MagnusJosefsson, PulverizingPancake, rmn, ascension, mathpesto, krillin, filmore, jkuo7, Blake Saligia, dunder, ... Vasefire, sugardude, Lizzy01, adalg, lerroyy, MusiKaiser, functor, puzzler05, Snookerfan, konklone, Tom-dz, hoogachakka, Statistica, Asphodel, wpolly, Myxo, Uhu, Zzzyxas, ManuH, dogfarts, kamkam
Full list

Comments

on 12. September 2023, 15:49 by Snookerfan
Brilliant puzzle! Thank you

on 22. July 2023, 09:29 by tesseralis
So this was the last puzzle I made before I went on hiatus (I got a rubiks cube for my birthday and got really into speed cubing). Thank you all for solving my puzzle and the lovely comments <3

on 23. June 2023, 12:49 by sugardude
This one is just out of world. So, so unbelievably beautiful from start to finish. Thanks!

on 28. May 2023, 06:11 by Tacosian
Absolutely incredible puzzle. Loved it.

on 3. April 2023, 13:41 by CahounCZ
Incredible puzzle, thanks.

on 25. March 2023, 19:02 by Agent
Incredible construction! Glad I was finally able to tick this one off my bucket list. It's astonishing that the puzzle flows so well with such a large grid.

on 20. February 2023, 02:47 by wooferzfg
An awesome puzzle and a fun solve where we didn't really get stuck at all. I absolutely loved the ending.

on 20. November 2022, 01:38 by Christounet
Colossal indeed ! Magical, phenomenal, unreal as well !
The hardest thing is to keep an eye out for silly mistakes here, which can easily get lost in the immensity of the grid going forward... Loved the final resolution, which undoubtedly proved how well crafted that puzzle is ! It definitely lived up to the masterpiece it’s inspired from. A big thank you !

on 18. November 2022, 16:31 by Niverio
It is a big wonder how this puzzle got rated as 5 star difficulty. It felt more like a 3/5 to me, it was just long. Splendid!

on 3. November 2022, 03:22 by mathpesto
Wow! Despite having to restart a few times due to foolish errors, I enjoyed every minute of this. As others have said, no individual step felt too tricky—it's just a matter of maintaining laser focus and asking the right questions in the right places. I can safely say this is one of my all-time favorite puzzles :)

Last changed on 29. October 2022, 15:39

on 29. October 2022, 15:39 by MagnusJosefsson
Fantastic! So great to see more colossal-size puzzles :). This one worked very well, being interesting all the way through while never being difficult. Very enjoyable!

on 28. October 2022, 08:27 by Jesper
Great puzzle, very fun concept!

Last changed on 28. October 2022, 07:19

on 28. October 2022, 06:43 by henrypijames
I expect a colossal Yin-Yang within the week.

Seriously, consider this ruleset:
1. Classic YY for the colossal grid.
2. Each unshaded cell is awarded a number equal to the median distance it can see in all four orthogonal directions, while shaded cells block vision and remain empty.
3. The median of all unshaded cells in each block of the colossal grid is the sudoku digit (this median of medians allows for crazy stuff like unshaded 0, 1½, 4½, 12½ to produce a 3).
--
henry, create the puzzle you want to see in the world ^_^ ~tess

on 28. October 2022, 06:26 by RJBlarmo
Wonderful puzzle! Nothing too tricky, but some of the ending steps did take me a while.

64x64 puzzle when? (just kidding please don't)

on 28. October 2022, 05:44 by KNT
Absolutely lovely! Not difficult, just a very pleasant, large cave to enjoy. A pleasure to test :)

on 28. October 2022, 05:10 by AstralSky
This is just incredible!

on 28. October 2022, 04:13 by h5663454
Stunning!
But it still took me almost 4 and a half hours...

on 28. October 2022, 03:21 by tesseralis
Fixed solution code

Last changed on 28. October 2022, 03:35

on 28. October 2022, 03:13 by peterkp
The puzzle looks intriguing, but can you please clarify the Sudoku part of the rules? I am looking at the example and see no connection between the Sudoku grid and the Cave grid. eg, what does the 1 in R1C1 relate to?

--

Each 3x3 box in the cave grid (or 2x2 box in the example) corresponds to a single digit in the sudoku grid. For example, the top-left 2x2 in the example has one unshaded cell, so R1C1 in the sudoku is a 1.
====
Ahh, now I understand! Thanks for taking the time to explain.

Difficulty:5
Rating:99 %
Solved:56 times
Observed:14 times
ID:000BTK

Puzzle combination Puzzle variant Variant combination

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Solution code:

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