Sudoku Variants Series (333) - Odd or Even Sandwich Sudoku
(Published on 11. August 2021, 00:00 by Richard)
Odd or Even Sandwich Sudoku
Inspiration for this type comes from Hu Mengting.
Solve online in Penpa+ (thx again to Henry!)
Apply classic sudoku rules.
If the first cell in a row or column contains an even digit, clues outside the grid indicate all the digits that have even digits neighbouring them on both sides in the corresponding row or column. If the first cell contains an odd digit, clues indicate all the digits that have odd digits neighbouring them on both sides. Clues outside the grid are written in an ascending order, which is not necessarily the order in which they appear in the grid. A dash implicates that no digits meet this requirement.
Solution code: Row 2, followed by column 9.
Comments
on 7. November 2022, 23:28 by Nylimb
I really enjoyed the logic in this one. Thanks!
on 30. September 2021, 11:28 by Hausigel_mod
Parity tag added
on 23. August 2021, 19:27 by pin7guin
Ich mag Paritäten! :-)
on 11. August 2021, 22:43 by SudokuExplorer
Very enjoyable parity variant! The break-in was well-telegraphed and after the next key step, it went very smoothly, thanks! :-)
on 11. August 2021, 17:47 by Mody
Mal wieder klasse :)
on 11. August 2021, 17:41 by ibag
Sehr schön und flüssig zu lösen. ;-)
on 11. August 2021, 14:07 by marcmees
Very nice. I must admit that I struggled a bit with the "-" at the start and now I finished SVS333 I can't say why. Very straightforward solve once I got my head wrapped around the rules. thanks again.
on 11. August 2021, 10:35 by zuzanina
Sehr schön, vielen Dank!
on 11. August 2021, 05:32 by Richard
@Henry: the entry in this puzzle is not that hard once you understand the way the instructions work. By the looks of it you had some problems with that. I will write the first few steps of the logical solve in a hidden comment.
on 11. August 2021, 05:30 by Richard
Added to the instructions that the clues outside the grid are written in ascending order.
on 11. August 2021, 05:22 by Richard
Added link to online solving. Once more a big thank you to Henry!
on 11. August 2021, 04:08 by henrypijames
Very, very slow going to get started. But once broken in, it was smooth sailing. Did you take my comment from last week to heart and decided to switch things up, @Richard? ;)
on 11. August 2021, 04:06 by henrypijames
My suggestion: Clues outside a row/column give all digits in that row/column, each of which is individually sandwiched within that row/column between immediate neighbors with the same odd/even parity as the first (top/left most) digit of that row/column. Digits in the clues may appear in any order within the corresponding row/column. A dash clue indicate no digit is sandwiched in the aforementioned manner.
This phrasing is still anything but easy to understand, but at least much more precise. A visual example (like the one from the referenced puzzle) is mandatory for this ruleset, I think.
on 11. August 2021, 02:30 by cdwg2000
@henrypijames
If the first cell is an odd number O, the external prompts are X, Y and Z, and the corresponding methods are OXO, OYO, OZO; the first cell is an even number E, and the external prompt is ABC, and the corresponding methods are EAE, EBE , ECE; The order of XYZ and ABC is not restricted; if the external prompt is -, the first cell is odd O/E, there must be no O? O format or E? E format.
If you have a better description, please let me know, thanks!
on 11. August 2021, 02:18 by henrypijames
The wording of the rules is ambiguous in two aspects: 1. How does "both sides" apply to first/last row/column? Just one side or toroidal? 2. Does "corresponding row/column" mean same row/column or the row/column indicated by the first digit or the given digit?
EDIT: I misunderstood even more than I thought! I thought a clue for R3 refer to digits and their neighbors in R2 and R4, not in R3 itself. The wording from the referenced puzzle is better but still not good - only the given example made things clear.
Penpa+: https://git.io/JRK8G
