Logic Masters Deutschland e.V.

Miracle in Entropia

(Published on 9. January 2024, 11:40 by Mad-Tyas)

This puzzle is certainly the most incredible discovery yet for Entropy sudoku: Entropy/Skyscraper with a unique solution with only 2 (!) clues.
It's also easily the most difficult Entropy sudoku I've published. But there is at least one logical path to solve it. I had to search for that path for a long time myself and I'm glad I found it. Because now I can present this mad miracle with a clear conscience.

Rules:

Sudoku: Fill every row, column and marked 3x3 box with the digits 1-9.

Skyscraper: Consider each digit in the grid as a building of that height. Clues outside the grid give the number of buildings that can be seen from that direction, with larger buildings hiding smaller ones.

Entropy: Each 2x2 box in the grid has to contain a low digit (1, 2, 3), a middle digit (4, 5, 6) and a high digit (7, 8, 9).

Have fun solving!

Sudoku on:
CTC-App
f-puzzles

Solution code: Row 9 (9 digits)


Solved by jalebc, Megalobrainiac, Dentones, samuel1997, SKORP17, ancarro, h5663454, Playmaker6174, PierreTombal, TrollErgoSum, Xalothros, Snookerfan, ohnoitsadalek, itweb, akamchinjir, AKernel, jseng, palpot, flipout, nordloc, ascension, Silverstep, DaleVandermeer, SirJefferE, Mikemerin, quantumquark1, SXH, Brodie2000, Zzzyxas, shteev, PippoForte, finger, Blake Saligia, 0123coolkid, arteful
Full list

Comments

on 28. September 2024, 21:16 by 0123coolkid
This was an absolute BEAST of a puzzle, I can't believe I got through it!! It's crazy to see how powerful the entropy constraint truly is. Thanks for setting Mad-Tyas :)

on 25. June 2024, 20:04 by shteev
Daaaamn this is surely the hardest Mad-Tyas entropy puzzle I've ever done, I think I've been picking away at this one for months.

Thanks for setting, tho <3

on 7. March 2024, 09:25 by SirJefferE
Whew! Thought I'd go mad during the middle portion. Row six was nasty!

on 8. February 2024, 05:21 by Silverstep
5/5 difficult for sure. global entropy is very powerful, and logical deductions can hide in places you least expect.

Last changed on 11. January 2024, 14:29

on 11. January 2024, 11:18 by ohnoitsadalek
i really love these global entropy puzzles! interesting to see how it increases with high value skyscraper clues

-Reply: Thank you for solving and your comment! It's always a pleasure to read that someone loves the global entropy constraint.

Last changed on 11. January 2024, 14:28

on 11. January 2024, 09:58 by Snookerfan
Incredible puzzle! Took me just under 6 hours to solve logically. 12 stars for difficulty, but really a miracle grid. The only reason I didn't give up was that your puzzles are always absolutely brilliant and worth my time. Thank you

-Reply: Thank you very much for taking so much time to logically work your way through the puzzle! I always appreciate your comments on my puzzles. "12 stars for difficulty" made me laugh :-D
But considering some other entropy puzzles that were rated 5 stars for difficulty it seems appropiate.

Last changed on 11. January 2024, 14:20

on 10. January 2024, 11:23 by PierreTombal
I wasn't real proud of my solve as the last steps I took felt like bifurcation. So I rewound to the point where it still conformed to logic and found that there really does exist a logical path that would have been a lot simpler if only I had remembered to do sudoku rather than focus so hard on the entropy rule.

-Reply: Thank you very much for solving and your comment! It's really nice to have the existence of a logical path confirmed by other solvers.

on 10. January 2024, 10:14 by Playmaker6174
(That aside, I actually enjoyed how much works just one 8 clue can deliver, that was mindblowing)

Last changed on 11. January 2024, 14:17

on 10. January 2024, 09:56 by Playmaker6174
This puzzle is so monstrously hard that it burned the entire battery of my phone and then almost half of it in the next day. Miraculous indeed but my god…

-Reply: Wow! I don't really know if I should feel sorry or proud about that. I'm overwhelmed that you take so much time to work on my puzzle. Thank you so much!

Last changed on 11. January 2024, 14:11

on 9. January 2024, 16:49 by h5663454
When the digits was determined through row 6, I suddenly had an idea... Is this puzzle just created by the author just to show off his skills?

p.s.: At least my current situation is: through the clues on the left side of the row 1, I have determined a few digits and the coloring distribution of boxes 1, 2 and 3.

Then, when I set my sights on the 7 on the right side of row 6, and spent a long time thinking about it, I finally had to unilaterally declare that *this puzzle can only be solved through brute force enumeration *…

-Reply: Thanks for solving the puzzle and your comment! Of course it isn't my intention to frustrate a solver with one of my puzzles. And if this was your experience I'm sorry for that.
I decided to publish this puzzle for two reasons:
1. It fascinates me that there is a unique solution for such a minimalist construction.
2. I know there are some solvers, who like very hard entropy puzzles and this puzzle felt appropriate to provide a new challenge to those.

Difficulty:5
Rating:87 %
Solved:35 times
Observed:8 times
ID:000GHN

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