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a few killer sudokus
http://www.calcudoku.org/forum/viewtopic.php?f=19&t=259
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Author:  pnm  [ Wed Jun 27, 2012 6:18 pm ]
Post subject:  a few killer sudokus

At some point I realized that, because a "Killer Sudoku" is really a Calcudoku
with some restrictions (the 1-9 in a 3x3 block rule, and only using the + operator),
I could make a few small modifications to my generator, and create Killer Sudokus :-)

A sample is below. It's very easy, because my solver doesn't (yet) use the "3x3 block rule".

Image

Feedback welcome :)

Author:  clm  [ Wed Jun 27, 2012 8:59 pm ]
Post subject:  Re: a killer sudoku

pnm wrote:
At some point I realized that, because a "Killer Sudoku" is really a Calcudoku
with some restrictions (the 1-9 in a 3x3 block rule, and only using the + operator),
I could make a few small modifications to my generator, and create Killer Sudokus :-)

A sample is below. It's very easy, because my solver doesn't (yet) use the "3x3 block rule".

...

Feedback welcome :)


Very interesting, I have always liked the Killer sudoku's and I used to do them (along with the kakuros) when the calcudoku did not exist. Reasonably easy (it took me around 15-20 minutes, but for me it's the first after 3 or 4 years) but not "specially" easy for those who are not very familiarized with the "sudoku" or the "killer" techniques. It's a good new that your software can generate these. Perhaps you may include one of these (i.e., once per month) as the extra puzzle for subscribers, no matter if it brakes the "pure" calcudoku rules in favour of the 3x3 block "rule" [thumbup].

Author:  picklepep  [ Thu Jun 28, 2012 3:32 am ]
Post subject:  Re: a killer sudoku

pnm wrote:
At some point I realized that, because a "Killer Sudoku" is really a Calcudoku
with some restrictions (the 1-9 in a 3x3 block rule, and only using the + operator),
I could make a few small modifications to my generator, and create Killer Sudokus :-)

A sample is below. It's very easy, because my solver doesn't (yet) use the "3x3 block rule".

Image

Feedback welcome :)

What is the operand? Is it just addition?

Author:  pnm  [ Thu Jun 28, 2012 10:35 am ]
Post subject:  Re: a killer sudoku

picklepep wrote:
What is the operand? Is it just addition?

Yes, that's a "killer sudoku" thing.
(stupid name for a puzzle)

Author:  pnm  [ Thu Jun 28, 2012 4:30 pm ]
Post subject:  Re: a killer sudoku

While I'm at it, here's another one:

Image

Author:  pnm  [ Fri Jun 29, 2012 12:22 am ]
Post subject:  Re: a few killer sudokus

And another one below. I've now improved the "killer sudoku solver", and can
tell you that the puzzle above is easy, and that this one is quite hard.

I read about another rule difference for killer sudoku: you can not have the
same digit in a cage (!)(so only relevant for cages of size 3 and above,
non-straight, and crossing the "3x3 cube" boundaries)

Image

Author:  clm  [ Fri Jun 29, 2012 7:59 am ]
Post subject:  Re: a killer sudoku

pnm wrote:
While I'm at it, here's another one:

...


The second one is much easier than the previous one. In my opinion you should improve a little bit the graphics (if possible), I think a continuous line (very slim) is better than the dotted line but, in both cases, if you are able to eliminate those "gaps" among the dots, the puzzle would be more clear.

We could rename it to "addition sudoku" [biggrin]; BTW, it would be interesting to know from where it comes the name "killer" (in the case of the "samurai" it probably comes from the aspect of the 5 sudokus together), perhaps it is a "bad" translation from some japanese name because it reminds the presence of "knifes" or something similar that "attack" the near cages ... [biggrin].

With respect to your last observation (the rule of non repetition of numbers in the cages) I remember that in the past it was a big discussion about this, and there are many authors who do not agree, I have solved the "killer's" with and without that "rule", generally all coming from Japan.

Author:  pnm  [ Fri Jun 29, 2012 9:29 am ]
Post subject:  Re: a killer sudoku

clm wrote:
I think a continuous line (very slim) is better than the dotted line but, in both cases, if you are able to eliminate those "gaps" among the dots, the puzzle would be more clear.

Yes, currently it's a small "box within a box" (easy way out..), I'll improve that.
I was also thinking of doing the dotted lines in slightly different colours.
clm wrote:
We could rename it to "addition sudoku" [biggrin];

Well, at least for this name there is consistency: no company coming after
you if you use it...
clm wrote:
With respect to your last observation (the rule of non repetition of numbers in the cages) I remember that in the past it was a big discussion about this, and there are many authors who do not agree, I have solved the "killer's" with and without that "rule", generally all coming from Japan.

Interesting. Maybe I'll change it back then, to make them more similar to the Calcudoku.

Patrick

Author:  pnm  [ Fri Jun 29, 2012 2:47 pm ]
Post subject:  Re: a few killer sudokus

slightly improved layout, and coloured borders (easy one this one):

Image

Author:  clm  [ Fri Jun 29, 2012 6:43 pm ]
Post subject:  Re: a few killer sudokus

pnm wrote:
slightly improved layout, and coloured borders (easy one this one):

...


Very clear layout now (we must wait for the 3 or 4 cell cages ... ), btw, the nr. 3 is a little bit more difficult than the previous 1 and 2, but not too difficult. Are you using the same algorithm to obtain the "solving rate" for these "addition" sudokus?.

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