The hardest sudokus (new thread)

Everything about Sudoku that doesn't fit in one of the other sections

Re: The hardest sudokus (new thread)

Postby tarek » Sun Aug 18, 2019 11:55 am

There is no standard for the representation of a pencilmark grid in a line format. The 729-character line representation has benefits but having delimiters will certainly shorten the lines in most cases. In the Sukaku explainer project we are working on at the moment we are using the 729-character line and the multi line pencilmark grid. So it appears that the 729-character is becoming more of a standard as more people use it.

If you are using delimiters especially spaces may have issues with sharing and posting them as you can’t control how the message board formats them. The 729-character line has less problems in the way.

We are currently working on a project on github to improve Sudoku explainer and allow rating of Sukaku. The puzzles I posted remain challenging without a rating as we speak because of the time required to process even a single elimination

Tarek
User avatar
tarek
 
Posts: 3024
Joined: 05 January 2006

Postby Pat » Sun Aug 18, 2019 12:04 pm

denis_berthier wrote:Is there any problem with spaces in a line?

i would use a colon (":")
to separate the cells

    ( as used in URL for dailysudoku )
User avatar
Pat
 
Posts: 3820
Joined: 18 July 2005

Re:

Postby tarek » Sun Aug 18, 2019 1:06 pm

Pat wrote:
denis_berthier wrote:Is there any problem with spaces in a line?

i would use a colon (":")
to separate the cells

    ( as used in URL for dailysudoku )

I’m hoping that the next release of Sukaku explainer will allow Pasting into GUI these multiple formats which in theory should allow pasting any pencilmark grid (sudoku or Sukaku) and continue solving/analysis from that point in the pencilmark grid
User avatar
tarek
 
Posts: 3024
Joined: 05 January 2006

Re: The hardest sudokus (new thread)

Postby dobrichev » Sun Aug 18, 2019 3:40 pm

denis_berthier wrote:Another question about these puzzles: has anyone finally found a solution to compute their SER?


No.

SE had one elimination technique at the bottom which failed to rate them. All known vanilla puzzles don't use it.
This enforced us to make changes in the techniques beyond the ones that solve vanilla sudoku.
So far the extension gives some more eliminations but still fails to solve them.

In this context, at the moment we have an extension to SE which gives some number for a puzzle, but this shouldn't be considered as "SE rating" when technique beyond the old one is in use.

The 999_Springs example uses only old techniques and its result can be considered SER.

Technically SE now accepts 729-char pencilmarks as input, can dump the solving steps, and does ~17 hours processing on a 4-core machine to ensure the puzzle is beyond the implemented techniques.
dobrichev
2016 Supporter
 
Posts: 1711
Joined: 24 May 2010

Re: The hardest sudokus (new thread)

Postby blue » Mon Aug 19, 2019 6:49 am

Hi Denis,

denis_berthier wrote:A more interesting question for me would now be: can one find a Sukaku not in B7B?

Tarek's "singles backdoor size 6" puzzles are all "TE[singles](4)" -- "in BBBB, but not in BBB".
There were two more puzzles of interest, mentioned here:

The others (with high SE ratings) were "TE[singles](2)", and so in BB.
I can't say whether they're in B7B.

Cheers,
Blue.
blue
 
Posts: 853
Joined: 11 March 2013

Re: The hardest sudokus (new thread)

Postby denis_berthier » Mon Aug 19, 2019 1:03 pm

Hi Blue,

blue wrote:
denis_berthier wrote:A more interesting question for me would now be: can one find a Sukaku not in B7B?

Tarek's "singles backdoor size 6" puzzles are all "TE[singles](4)" -- "in BBBB, but not in BBB".
There were two more puzzles of interest, mentioned here:


Thanks for your answer; it totally solves the question for me. Having Sukakus in T&E(4) or even T&E(3) - i.e. intractable - is enough to show that Sukakus can be terribly harder than Sudokus.

denis_berthier wrote:The others (with high SE ratings) were "TE[singles](2)", and so in BB.
I can't say whether they're in B7B.

If there are Sukakus in B3B, I have no doubt that there are also Sukakus in BpB for some p > 7. Unless anyone is interested in knowing about these two particular ones, I see no point in checking.
I fear this also puts an end to my short-lived interest for the hardest Sukakus.
denis_berthier
2010 Supporter
 
Posts: 1275
Joined: 19 June 2007
Location: Paris

hello guys i am checkvil

Postby checkvilelurl » Tue Aug 20, 2019 10:29 pm

i am Checkvil. This i my login on this forum. it is good ? :)
User avatar
checkvilelurl
 
Posts: 1
Joined: 20 August 2019
Location: Mongolia

Re: The hardest sudokus (new thread)

Postby ssxsssxs » Mon Sep 02, 2019 4:50 am

new 11.7
Code: Select all
120300000600070010004005000300000400060020030008000009000900008070030060000002500  ED=11.7/1.2/1.2
User avatar
ssxsssxs
 
Posts: 159
Joined: 22 January 2014

Re: The hardest sudokus (new thread)

Postby tarek » Mon Sep 02, 2019 7:41 am

This puzzle solved successfully in the Sukaku explainer and would get the following rating combination:

Code: Select all
11.7/1.2/1.2 DCFC+DFC/HS/HS

with the hardest step at

Code: Select all
+-------------------+-------------------+-------------------+
| 1     2     579   | 3     4689  4689  | 6789  4589  4567  |
| 6     3589  359   | 24    7     489   | 2389  1     2345  |
| 789   389   4     | 1268  1689  5     | 23678 2789  2367  |
+-------------------+-------------------+-------------------+
| 3     159   127   | 15678 15689 16789 | 4     2578  1267  |
| 4579  6     1579  | 4578  2     14789 | 178   3     157   |
| 2457  145   8     | 14567 1456  3     | 1267  257   9     |
+-------------------+-------------------+-------------------+
| 245   1345  136   | 9     1456  167   | 1237  247   8     |
| 24589 7     1259  | 458   3     148   | 129   6     124   |
| 489   13489 136   | 14678 1468  2     | 5     479   137   |
+-------------------+-------------------+-------------------+


Image
You can pick a more difficult one as well

Image
User avatar
tarek
 
Posts: 3024
Joined: 05 January 2006

Previous

Return to General