[Kde-games-devel] Killer Sudoku / Mathdoku

[Richard Llom]

Ian Wadham wrote:
> Hi Richard and Ronald,
> On 06/04/2015, at 7:59 PM, Richard Llom wrote:
>> Ian Wadham wrote:
>>> On 25/03/2015, at 5:43 AM, Ronald Ellison wrote:
>>>> 
>>>> http://killersudokuonline.com/play.html?puzzle=D34b3vy2894&year=2013
>>>> 
>>>> This puzzle brings simple maths into Sudoku and I find it the most
>>>> addictive of all.
>>> 
>>> I have done some Googling around re Killer Sudoku and I must say it does
>>> pose an interesting design and programming challenge.  The problems are
>>> to find a Killer Sudoku generator, an accurate difficulty grader and a
>>> Killer Sudoku solver.
> 
> You will be pleased to hear that I have added Mathdoku and Killer Sudoku
> to KSudoku, with a DLX (Dancing Links) solver.
> 
Cool :-)

> The Mathdoku is working
> quite well, with sizes 3x3 up to 9x9, selected in the Settings dialog. It
> still needs some user-friendly messages to be added, plus a little
> "tuning" to ensure that the puzzle generator always behaves itself.
> 
> There is a 4x4 Tiny Killer, but the full 9x9 Killer Sudoku is on hold
> until I  can get it to generate more realistic and interesting puzzles. 
> They are far too hard ATM - too many possibilities and not enough leads,
> even when using "rule of 45", "innies", "outies" and other tips.
> 
Not so sure about this, I think 9x9 is supposed to be incredibly hard. The 
difficulty raises with the grid size and I don't think its linear. From my 
Androip app for mathdoku[1] the new game / difficulty settings reads like 
this:
4x4 easy
5x5 medium
6x6 hard
7x7 harder
8x8 hardest
9x9 ultimate

I mostly play 5x5 (around 8min) and 6x6 (~17 min) never went above...

> Also, the KSudoku
> graphics and themes are going to need work in order to display square
> 3x3 blocks and cages simultaneously without looking messy.
> 
> The source code has been committed to the KSudoku repository master
> branch and I expect it will be released in August in the KDE Applications
> 15.08 release, see
> https://techbase.kde.org/Schedules/Applications/15.08_Release_Schedule
> 
>> Actually "Killer" Soduko is just subset/variant of KenKen:
>> https://en.wikipedia.org/wiki/KenKen
>> Due to trademark issues this is often available as Mathdoku (which is
>> also a more fitting name, IMHO), e.g.
>> https://play.google.com/store/apps/details?id=net.cactii.mathdoku
>> This app is open source and the source is here:
>> https://code.google.com/p/mathdoku/source/browse/
> 
> That Java code was a good source of ideas, as well as some other code
> I found for DLX solvers.  Thanks, Richard.
Glad I could help. :-)

> Nobody seems to have a good
> algorithm for predicting the difficulty of a generated Mathdoku or Killer
> Sudoku puzzle - or if they do, they are not publishing it… ;-)
> 
See above, maybe there isn't such and they just get harder by size. But 
below is also another source to checkout ;-).

> All the best, Ian W.
Cheers
richard


[1]
https://code.google.com/p/holoken/