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 RW » Sun May 29, 2011 11:12 am

dobrichev wrote:Here are the results for the puzzles from Patterns Game 141


Very nice! There does seem to be quite strong correlation between sum(solved cells) and the difficulty. Of course there are some exceptions, but in general the harder puzzles have much fewer solved cells. Interesting to see a few with 0 solved cells, this means that you cannot solve a single cell in that puzzle without taking into account information from every single given clue! The high count for the last puzzle comes only from the fact that it starts with a hidden single, which is counted 18 times. Removing 18 of the 22 given clues we can still solve the same hidden single.

I'm planning to look more into this issue later, too busy at work right now. But maybe in a couple of weeks.

RW
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Re: The hardest sudokus (new thread)

Postby coloin » Wed Jun 01, 2011 1:28 am

Of course my study was woefully small !

However your data is excellent - and indeed the large unavoidable sets are not so uncommon.
I wonder what the important data is however -

the smallest max unavoidable seems important.
Also the figure for solved clues seems relevant [are you sure the value of the solved cells is 16 and not 1 for tarx075]

I cant see how the 3.6/3.6/3.6 comes out so favourable - except it does have a small max unavoidable for two of the clues.

It doesnt look as this is the complete picture - but we sure are a wee bit closer !

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Re: The hardest sudokus (new thread)

Postby dobrichev » Wed Jun 01, 2011 4:37 am

coloin wrote:are you sure the value of the solved cells is 16 and not 1 for tarx075

The results for this puzzle:
Hidden Text: Show
Code: Select all
........6..5..18...9...8.7....8.2.....3.1.2..4..5.3....6.....9...83..1..7.......4 # tarx0075
........6..5..18...9...8.7....8.2.....3.1.2..4..5.3....6.....9...83..1..7.......4       22
        1       8       91      53      #Clue,pos,numUA,maxUAsize

        2       11      114     49      #Clue,pos,numUA,maxUAsize

        3       14      157     50      #Clue,pos,numUA,maxUAsize

        4       15      311     52      #Clue,pos,numUA,maxUAsize

        5       19      130     54      #Clue,pos,numUA,maxUAsize

        6       23      8       53      #Clue,pos,numUA,maxUAsize
                1       ..............................................2..................................       #nSolved,solved

        7       25      126     49      #Clue,pos,numUA,maxUAsize

        8       30      58      49      #Clue,pos,numUA,maxUAsize

        9       32      109     52      #Clue,pos,numUA,maxUAsize

        10      38      428     51      #Clue,pos,numUA,maxUAsize

        11      40      4       41      #Clue,pos,numUA,maxUAsize
                15      .8....9..6.......2...6..............8..4.9....2....7................6..7.3...56..       #nSolved,solved

        12      42      319     52      #Clue,pos,numUA,maxUAsize

        13      45      132     53      #Clue,pos,numUA,maxUAsize

        14      48      17      46      #Clue,pos,numUA,maxUAsize

        15      50      24      44      #Clue,pos,numUA,maxUAsize

        16      55      167     48      #Clue,pos,numUA,maxUAsize

        17      61      41      48      #Clue,pos,numUA,maxUAsize

        18      65      92      49      #Clue,pos,numUA,maxUAsize

        19      66      173     53      #Clue,pos,numUA,maxUAsize

        20      69      225     52      #Clue,pos,numUA,maxUAsize

        21      72      125     49      #Clue,pos,numUA,maxUAsize

        22      80      150     52      #Clue,pos,numUA,maxUAsize
                        3001    54      16      #numUA,maxUAsize,nSolved

Additionally, the duplicates are counted, assuming the "solved cells" characterize the "removed clue" of the puzzle.
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the tool

Postby dobrichev » Wed Jun 01, 2011 6:01 am

The tool (incl. source) is available for downloading. See this post for details.
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Re: The hardest sudokus (new thread)

Postby coloin » Wed Jun 01, 2011 8:56 am

I see.
Those 15 clues are not in the uncovered unavoidable sets from the solution grid of the individual puzzle - but they are involved in the sets from the solution grids of the other [many] puzzle solutions.
This makes those other puzles with "0" solved cells perhaps more remarkable.

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Re: The hardest sudokus (new thread)

Postby coloin » Wed Jun 01, 2011 8:47 pm

Running the program on Golden Nuggett, Silver Plate and Easter Monster
Code: Select all
gridchecker --unav --minus1 < gn.txt                                                                                     
.......39.....1..5..3.5.8....8.9...6.7...2...1..4.......9.8..5..2....6..4..7.....       21      2842    55      109316  0
{53,50,55,53,53,53,48,49,53,54,54,54,50,50,55,51,52,49,53,49,55}        1093                                             
Total time 0.256 seconds.                                                                                                 
                                                                                                                         
gridchecker --unav --minus1 < sp.txt                                                                                     
1.......7.2.4...6...3...5...9..4........62.4....9..8....5.....3.6.2...8.7....1...       21      2974    56      113066  0
{55,50,50,52,45,49,47,49,52,50,51,50,50,53,52,56,52,53,56,49,56}        1077                                             
Total time 0.279 seconds.                                                                                                 
                                                                                                                         
gridchecker --unav --minus1 < em.txt                                                                                     
1.......2.9.4...5...6...7...5.9.3.......7.......85..4.7.....6...3...9.8...2.....1       21      2733    55      106068  0
{53,48,53,51,53,52,48,51,50,52,51,55,53,49,53,52,53,53,51,51,51}        1083                                             
Total time 0.210 seconds.


looks promising and fast !

maybe suggest rating for gn to be some or all of 1093/21 * 48 * 55

will look at a few more puzzle perhaps
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Re: The hardest sudokus (new thread)

Postby coloin » Wed Jun 01, 2011 11:15 pm

This puzzle = found by eleven - has a very high suexrat9/suexratt rating
Code: Select all
rating:  10403 ,    5762 , ..3......4...8..36..8...1...4..6..73...9..........2..5..4.7..686........7..6..5..   

Code: Select all
..3......4...8..36..8...1...4..6..73...9..........2..5..4.7..686........7..6..5..       22      21523   53      813602  44
{51,48,48,53,50,51,48,48,49,48,49,48,50,28,50,48,43,47,52,50,45,49}     1053   


And there happens to be a plethera of unavoidables with many of the clues. Which might explain suexrat9's problem.

The min UA of 28 and the 44 solved cells might be the puzzles weakness.

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Re: The hardest sudokus (new thread)

Postby champagne » Wed Jun 15, 2011 8:34 am

Hi,

I continue to slowly explore the 22 clues field.
The current step if more productive than the first one, but for the time being, I will publish only some puzzles having specific properties.

Here is, as far as I know, the highest diamond ever found up to now.

98.7.....6.....8....7....5..4..3...2..96..4.......4.1...85..6......1..4......2..3;11.5;11.5;11.5

I hope to have in hands soon "skfr" (sudoku fast rating) the "quasi clone" rating version of Sudoku Explainer.

I'll then re rate all the puzzles that in my opinion worth it and try a summary complementary to the nice work done by eleven

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New update next weekend

Postby tarek » Sat Jun 18, 2011 12:27 pm

The next update will hopefully take place next week. All the ratings have been done. What is left is the slow Suexrat 10000 rating which should be finished before then.

I found 4 posted puzzles that have been posted before as well

Code: Select all
HardestSudokusThread-01458
1...5...9...7..1........56.2...6..1...4..8..2.3........7...4...6...2.9....83..... Posted Puzzle
1...5...9...7..1........56.2...6..1...4..8..2.3........7...4...6...2.9....83..... Canonical
1.......5.2.4...6...3...7...4...6.......49.8...28.........5.1...6.9...2...7.....3 col803

HardestSudokusThread-01459
1...5......7..9....8.2....4..5..7....3.6....29......1.....62......3..8...6....4.3 Posted Puzzle
1...5......7..9....8.2....4..5..7....3.6....29......1.....62......3..8...6....4.3 Canonical
1....5....6.2...4...3...7...4.69........8..6.......2.4..7...1...8.9...2.5.......3 colx022

HardestSudokusThread-01472
....5.7..4....9.3..8......12....4.6....7....8....1.5..3.2....9....94.....6...3... Posted Puzzle
....5.7..4....9.3..8......12....4.6....7....8....1.5..3.2....9....94.....6...3... Canonical
1....5....6.2...4...3...7...4.69.........8.6.......2.4..7...1...8.9...2.5.......3 colx015


HardestSudokusThread-01484
.....6.8....1..2...9..7...4.....86..3...4...5..52......3.......74.....1.9...3...7 Posted Puzzle
.....6.8....1..2...9..7...4.....86..3...4...5..52......3.......74.....1.9...3...7 Canonical
..1.....7.2..4..6.3.....5...9.4.6.......92.4.......8....7..3....6..2..8.5.......1 weekender2
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Re: The hardest sudokus (new thread)

Postby champagne » Sun Jun 19, 2011 8:45 pm

To continue like in the pattern game, here a puzzle equalling the highest ED I have in my database (2 puzzles rating 11.8).
So far, the highest rating for a 11.7 puzzle was 11.2 if I am right

98.7.....7.....9....6.5.....4..3..2...74..8.......1..4..86..5......4..1......2..3 ED=11.7/11.7/11.6

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HardestDatabase110626

Postby tarek » Sun Jun 26, 2011 8:52 pm

The Database has been updated. The Top 5 lists in the head post have also been updated.

You can now download the latest database using a link in the head post.

The list subsumes the previous list (HardestDatabase101230)

Champagne,
Your last puzzle is an isomorph of HardestSudokusThread-00051 with a different ER/EP/ED rating
I have updated the database with this new LOWER rating.
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Re: HardestDatabase110626

Postby champagne » Mon Jun 27, 2011 7:03 am

tarek wrote:The Database has been updated. The Top 5 lists in the head post have also been updated.

You can now download the latest database using a link in the head post.

The list subsumes the previous list (HardestDatabase101230)

Champagne,
Your last puzzle is an isomorph of HardestSudokusThread-00051 with a different ER/EP/ED rating
I have updated the database with this new LOWER rating.


hi tarek,

You are right. At that point, I had not yet checked for duplication.
I have that puzzle coming from eleven database

elev 16 1....6.8....7..1........5.6..9.4.....7.2...3.8....76..3....1..5.4.9.......2.7....

rated 11.8 11.8 11.6

BTW, rating in that area should be seen as an order of magnitude.

champagne
Last edited by champagne on Thu Jul 21, 2011 8:47 am, edited 1 time in total.
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Re: The hardest sudokus (new thread)

Postby champagne » Thu Jul 21, 2011 8:46 am

deleted
Last edited by champagne on Wed Aug 10, 2011 8:13 pm, edited 1 time in total.
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Re: The hardest sudokus (new thread)

Postby champagne » Fri Jul 22, 2011 9:01 am

Hi,

I am suspecting eleven was right thinking it would be possible to get more than SE ER 11.9.

I just got that puzzle with the highest known SE rating

Code: Select all
98.7.....7.....6....6.5.....4...5.3...79..5......2...1..85..9......1...4.....3.2. ;11.9;11.9;11.8



champagne

EDIT: I checked how that puzzle is seen by my solver. It has an EXOCET pattern and is relatively easy to solve.

I did not make so far a complete analysis of the new "hardest", but I know some appear much tougher to solve.

EDIT2: Some more comments on that puzzle.
I tested the Allan Barker mode included in my solver.
up to 5 floors, nothing came.
This means that it should be difficult to find something using XSUDO, at least without the UR mode
For Golden Nugget, a five floors construction is possible.
Last edited by champagne on Fri Jul 22, 2011 1:25 pm, edited 1 time in total.
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Re: The hardest sudokus (new thread)

Postby tarek » Fri Jul 22, 2011 10:33 am

champagne wrote:I just got that puzzle with the highest known SE rating

Code: Select all
98.7.....7.....6....6.5.....4...5.3...79..5......2...1..85..9......1...4.....3.2. ;11.9;11.9;11.8

Well done. I couldn't understand if this was a very recent find or that it had been there for some time but posted elsewhere.

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