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Isolated Sudoku
http://www.rcbroughton.co.uk/sudoku/forum/viewtopic.php?f=13&t=1544
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Author:  Quadrata [ Wed Feb 05, 2020 4:00 pm ]
Post subject:  Isolated Sudoku

Given a collection of numbers, the isolated numbers are ones in the collection with no consecutive numbers (on either side.) For example if the numbers are 1,3,4,6,8,9 then the isolated numbers would be 1 and 6 because 3 is next to 4 and 8 is next to 9. (Alternately we could say the isolated numbers are numbers n in the set so that both n+1 and n-1 are not in the set.)

Here is a Sudoku I constructed based around this one idea.

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For more information and the solution visit Quadrata.

Author:  HATMAN [ Wed Feb 05, 2020 7:51 pm ]
Post subject:  Re: Isolated Sudoku

Really sweet David

A good way of creating a Sukaku hence I suggest that you post it in the Sukaku thread on the players forum. This would make a change from their usual computers only Sukakus.

As every corner has a meaning I do not think that you can make these too difficult - but I'll try.

Maurice

Author:  HATMAN [ Tue Feb 11, 2020 7:07 am ]
Post subject:  Re: Isolated Sudoku

I've solved the problem of making them harder.
If we put the isolated numbers in a box then if the box is empty there are no isolated numbers. Whereas if there is no box no clue is given.


Isolated 2

Each number in a box means that the adjacent four cells contain that number but do not contain its adjacent numbers. So in nonet 1 the bottom left box means that there is a 2 in r23c12 and r23c12 does not contain 1 or 3. If a box has no clues then it are either two pairs or four consecutive numbers.

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Isolated 2 Hard

The same puzzle but three nonets have no boxes hence no clues.

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Author:  Quadrata [ Wed Mar 04, 2020 4:19 pm ]
Post subject:  Re: Isolated Sudoku

Maurice,

I really love what you did here. It looks great and the possibility for distinguishing where no clue is from where a blank clue is allows for us to make this clue type into what is really a challenging puzzle. I was waiting to write to you because I wanted to complete both puzzles first, but I've only completed the first one so far. I'm definitely going to go back to the second though!

-David

Author:  HATMAN [ Mon Mar 09, 2020 7:38 pm ]
Post subject:  Re: Isolated Sudoku

Isodoku 17, 17H, 18 and 19

Continuing with Quadrata's Isolated Sudoku concept and making it harder:
The blue quadrants contain four unknown singletons.
The pink quadrants contain two pairs.
The red quadrants contain a sequence of four (while this is giving extra information it can be used to leave out other clues).
No quadrant means that no clue is given.

The puzzle numbers have built up as I've been knocking them up and printing them to use as "go to sleep" puzzles.


Isodoku 17

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Isodoku 17 Hard

A harder version

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Isodoku 18

Note this is AN and FNC if you want to make it very easy.

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Isodoku 19

This is NC. I suggest you solve it that way first and then without the constraint.

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