Logic Masters Deutschland e.V.

Sea Sudoku

(Eingestellt am 9. Mai 2020, 20:09 Uhr von Sebas613)

Hello everyone, this is my 3rd handmade puzzle - and the most difficult.

I hope you enjoy it!


Standard Sudoku rules apply.

Killer Sudoku rules apply: inside an area contained by dashed lines, no number can be repeated. If a sum is indicated in the top left corner, all the numbers inside the area together need to sum to it.

On the edge of the two large bubbles every number needs to be followed by a number that is either higher by one or lower by one.

The 36 arrow indicates the sum of all the numbers on the diagonal, which can not contain repeated numbers.

Either both starfish need to indicate an even number, or both starfish need to indicate an uneven number.

Late rule addition: the numbers inside cells with circles cannot repeat. (Solves uniqueness issue). A > indicates that one cell is larger ( > ) than the other.

Link: https://tinyurl.com/SeaSudoku4 ( click here )

Please let me know what you think.

== Question: I've rated it 3 for now as I can't rate it 3.5 - can the first solver(s) let me know whether I should adjust it to 4 until the 10 solves are recorded? ==

Lösungscode: Top row and the row below it. Ex: 123456789 987654321

Zuletzt geändert am 9. Mai 2020, 22:47 Uhr

Gelöst von zhergan, marcmees, zorant, Mesmer, trivial171, Julianl, rimodech, ManuH, SirWoezel, NikolaZ, moss, skywalker, Imperial Marcher, sf2l, jetalix, saskia-daniela, ch1983, bob, geronimo92
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am 9. Mai 2020, 22:56 Uhr von Sebas613
My apologies to everyone who got confused before the fix; both the puzzle on the main page and the online version should be 100% unique now.

Zuletzt geändert am 9. Mai 2020, 22:57 Uhr

am 9. Mai 2020, 22:50 Uhr von Sebas613
@Zorant: Normally, when solving sudoku puzzles, when you have 12/1258 facing two 12-pairs in another box, you can eliminate the 12 from the 1258 cell for the reason that it would create a broken puzzle, like you observed. I was unaware that I couldnt use that constraint in setting up the puzzle, though it makes sense after reading Puzzle_Maestro's comment. (Since you using it after the fact still leads to the same solution (but is just one way out of many to get there), while me setting it up is my mistake as it actually does lead to a non-unique puzzle).

So you were right, there were initially multiple correct solutions.

am 9. Mai 2020, 22:47 Uhr von Sebas613
Added expl. regarding the >

am 9. Mai 2020, 22:46 Uhr von Sebas613
Solved for uniqueness.

am 9. Mai 2020, 22:26 Uhr von Sebas613
@Thanks Puzzle, that must be what confused me. I'll make a quick fix for the puzzle.

am 9. Mai 2020, 22:12 Uhr von Puzzle_Maestro
@Sebas613 You cannot use uniqueness techniques to verify that a puzzle has a single solution, as the techniques rely on the assumption that there is a unique solution, which you have not proven yet. As such, it should be easy to convince yourself that there are multiple solutions by trying different possibilities for cells. Don't worry, this is a very common mistake!

Zuletzt geändert am 9. Mai 2020, 21:57 Uhr

am 9. Mai 2020, 21:52 Uhr von Sebas613
@Zorant: You can remove the 1,2 where you have 1 in the 2nd row (317...) by using a unique rectangle. (I.e. specifically removing cell options which lead to multiple solutions). If I recall correctly, there are two "uniqueness" steps in total in the puzzle, near the end.

If people prefer, I could add in a single clue which would render those unnecessary.

am 9. Mai 2020, 20:35 Uhr von Sebas613
Slightly adjusted visuals on the linked version.

Bewertung:85 %
Gelöst:19 mal
Beobachtet:0 mal

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