Deranked (Full Rank Deconstruction)
(Published on 26. June 2023, 17:38 by the_cogito)
Rules:
- Place the digits 1-9 in the grid such that no digit repeats in any row or column.
- Place 9 nonoverlapping 3x3 square regions within the grid, each containing every digit 1-9 exactly once. Cells outside these regions do not contain digits.
- Values outside the grid are full rank clues. Consider all rows and columns in the grid as n-digit numbers when read from an edge of the grid, where n is the number of digits in that row or column. Full rank clues give the rank of their respective row or column in the direction from the clue. Smaller ranks indicate smaller numbers.
Note that in deconstructions of this type, r369c369 are always part of a region. My intention is not for unaware solvers to have to prove this themselves, thus this note.
I've taken the liberty of creating a small example puzzle, shown below, just to illustrate the rules. This example is both unique and solvable, feel free to give it a try. The green ranks outside of the solution are illustrative, and not part of the actual solution check.
Solve example on Penpa+
Solve example on SudokuPad (no answer check)
And now the main puzzle:
Solve on Penpa+
Solve on SudokuPad (no answer check)
Solution code: Row 6, then column 6. Skip over blank cells.
Comments
on 8. February 2025, 03:53 by Gnosis66
Generally, solvers don't remark on puzzles that were posted more than 18 months ago. However, this one was so intriguing and had such a satisfying solve that I had to comment.
on 7. January 2025, 14:42 by Christounet
Ridiculous that this can exist ! I can imagine the pain (or luck) to finally come to a valid grid...
Even if the idea of the opening can be intuited pretty easily, demonstrating properly the whole logical sequence takes some working (and in my case, paper and a pen).
Great stuff. Thanks :)
on 8. April 2024, 18:51 by Agent
Outstanding puzzle! Impressive that it solves so nicely with this ruleset.
on 12. January 2024, 23:49 by Fool on Hill
Just another outstanding construction
on 13. September 2023, 03:24 by sugardude
One of the hardest and best puzzles I've done on this site. AMAZING!!!
on 12. July 2023, 23:54 by shteev
Quite a mental load, this puzzle... Still, more fun than most 9 digit ranking puzzles!
on 4. July 2023, 11:27 by henrypijames
It's insane that this puzzle solves - and even more insane that someone actually set it.
on 3. July 2023, 04:15 by henrypijames
Does a completely empty row or column count as 0? Or is it excluded from the ranking? Or is it simply not allowed?
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An empty row or column would have a nonexistent rank I guess. It ultimately doesn't matter for this puzzle.
on 29. June 2023, 18:46 by MicroStudy
super trippy and a very one-of-a-kind puzzle!!
on 28. June 2023, 15:26 by bodemeister
Enjoyable puzzle for sure! I was really worried about finding enough n-digit numbers in a particular interval, but it worked out! Are you still skeptical about it getting a rating? :D
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Haha, less and less, this community is full of surprises sometimes :P I'm glad you liked the puzzle :)
on 28. June 2023, 08:17 by twobear
Great puzzle. Thank you!
on 27. June 2023, 11:19 by sanabas
Excellent puzzle.
on 26. June 2023, 22:19 by mnasti2
What a puzzle! Lots of cool stuff packed in there.
