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new book with Killer Sudoku puzzles
http://www.calcudoku.org/forum/viewtopic.php?f=19&t=317
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Author:  pharosian  [ Sat Sep 08, 2012 5:47 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pnm wrote:

Edit: for example, this is a good page:
http://www.sudocue.net/killerguide.php



Yes, that site does a very good job of explaining lots of things about how to solve Killer Sudoku puzzles, starting with the very basics... but they seem to assume the reader already knows what hidden and naked singles are. And this was the first time I'd heard those terms. [glare]

Author:  pnm  [ Sat Sep 08, 2012 6:17 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pharosian wrote:
Yes, that site does a very good job of explaining lots of things about how to solve Killer Sudoku puzzles, starting with the very basics... but they seem to assume the reader already knows what hidden and naked singles are. And this was the first time I'd heard those terms. [glare]

Thanks for noting that.

A lot of tricks/techniques have been assigned a name...

On hidden single: http://rishipuri.blogspot.co.uk/2010/12 ... ingle.html

About naked single, naked pair, etc.: http://www.sudokuwiki.org/naked_candidates

Author:  clm  [ Sat Sep 08, 2012 7:08 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pnm wrote:
clm wrote:
The graphics of the first 200 puzzles look better, I refer to the continuous lines (from 201 thru 250 the continuous lines overlap the dotted lines; though now the size is bigger probably with only the continuous lines would be enough, not both simultaneously).

I'm not sure what you mean: surely the puzzles look the same,
except 201-250 are larger?


Sorry, I think did not express it correctly, what I meant is that looking to the puzzles with the same scale: for instance, if you use the scale 100% with the Adobe Reader you do not see the dots in any of the 250 puzzles while if you go to a higher scale, i.e. 129%, then the first 200 puzzles do not show the dots but you see the dots and the continuous lines "overlapped" in puzzles 201-250, if you now increase again the scale to 150% then you have the continuous lines and the dots in all puzzles, is it not possible to suppress the dots "under" the continuous lines in all borders of the cages for any "scaling"? (that was what I tried to suggest, no problem with the exterior borders of the full puzzle or with the borders of the 3x3 boxes, these always show a continuous line).

Reedit: Amplifying to 800% it is observed a very slim continuous line and over that a series of much wider dots; I understand that most killer's designers use only dots for the borders of cages but I think it's not really necessary and it looks better with only the continuous lines.

Author:  pnm  [ Sat Sep 08, 2012 8:47 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

clm wrote:
Sorry, I think did not express it correctly, what I meant is that looking to the puzzles with the same scale: for instance, if you use the scale 100% with the Adobe Reader you do not see the dots in any of the 250 puzzles while if you go to a higher scale, i.e. 129%, then the first 200 puzzles do not show the dots but you see the dots and the continuous lines

It must be something specific to Adobe Reader then, I'll check here
(I don't use it myself, but should, because I'm guessing most people
use Adobe Reader for PDFs)

Edit: yes, I see that in Adobe Reader there are thin lines between the dashes (!)
They don't show in the PDF reader I use ("evince"). I'll try to fix it for Adobe Reader..

Patrick

Author:  pnm  [ Tue Sep 11, 2012 12:42 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pnm wrote:
Edit: yes, I see that in Adobe Reader there are thin lines between the dashes (!)
They don't show in the PDF reader I use ("evince"). I'll try to fix it for Adobe Reader..

I've tracked the cause: it's a bug in "inkscape", the program I use to create EPS files of
the puzzles (inkscape is a great piece of software by the way).

https://bugs.launchpad.net/inkscape/+bug/997595

Author:  pnm  [ Tue Sep 11, 2012 8:02 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pnm wrote:
I've tracked the cause: it's a bug in "inkscape", the program I use to create EPS files of
the puzzles

I've compiled and installed the latest version of Inkscape, but it still has the bug :-(
I've now found a solution by converting the puzzles to high-resolution images instead.
If all works well, I'll send people who've already bought a copy an updated version.

Patrick

Author:  pnm  [ Thu Sep 20, 2012 5:00 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pnm wrote:
If all works well, I'll send people who've already bought a copy an updated version.

I'm also re-rating the difficult puzzles
(also see this post: viewtopic.php?p=3196#p3196).

In the "Difficult" chapter, the harder puzzles are:

202
205
211
217
219
221
228
232
234
235
236
248

Of these, probably the hardest are 217, 221, 234, 236, and 248.

I'll probably:
- remove 25 easy puzzles
- add 25 difficult puzzles
- reorder the difficult puzzles

and then publish a 2nd edition (I'll send a free copy to people who bought the 1st edition, of course)

Patrick

Author:  pharosian  [ Thu Sep 20, 2012 5:25 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

pnm wrote:
In the "Difficult" chapter, the harder puzzles are:

202
205
211
217
219
221
228
232
234
235
236
248

Of these, probably the hardest are 217, 221, 234, 236, and 248.

That makes me feel much better. I gave up on 217 after being able to put numbers in only a small number of cells, and struggling for more than an hour to find any more.

I've been trying to keep track of how long it takes me to do each one, and 202 took me about half again as long as some of the easier ones.

I've finished 220, so it's good to have a warning about the other harder ones coming up.

Looking forward to the revision!

Author:  bram  [ Tue Feb 26, 2013 3:04 pm ]
Post subject:  Re: new book with Killer Sudoku puzzles

The harder puzzles from the "Difficult" chapter of the 1st edition that Patrick listed above have these numbers in the 2nd edition:

226 (b21d26)
229 (b21d9)
231 (b21d5)
240 (b21d13)
241 (b21d12)
243 (b21d28)
244 (b21d41)
245 (b21d34)
246 (b21d42)
247 (b21d39)
248 (b21d25)
249 (b21d48)

Of these, Patrick rated 243, 245, 247, 248 and 249 as probably the hardest.

So far I have only solved puzzles 176-221 from the 2nd edition, which means I haven't tried any of the hardest ones from the "Difficult" chapter of the 1st edition yet. I thought puzzle 220 (b21d53) from the 2nd edition (which wasn't in the 1st edition) was pretty hard, though [smile]

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