hardest 6x6?

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

Re: hardest 6x6?

Postby 999_Springs » Wed Apr 24, 2019 1:09 am

i had trouble getting the se-modified-for-6x6 thing set up, so i decided to convert what i could from the big pile of 542257 unique not-singles sudokus into 9x9s. i managed to convert 375052 of them into 9x9's (maybe another 1% or so is possible - my code is a bit buggy). i then rated them all with skfr as it's faster than se for now, and then double-checked the top end with se.

here is the distribution of 6x6s by clue count, and how many that were able to be converted to 9x9s
Code: Select all
clues, unique 6x6s, convertible to 9x9s
8  0      0
9  103    2
10 5323   1630
11 38778  19053
12 84895  49736
13 101229 64816
14 98356  68931
15 82129  61720
16 58576  46568
17 35903  29937
18 19622  16934
19 9715   8389
20 4613   4093
21 2075   1737
22 625    573
23 242    215
24 59     58
25 14     14

here is the distribution by skfr rating. note that there may be some differences between skfr and se, such as most or all skfr 6.9's being se 7+ (haven't found one that's not yet) and some 7.7's being 7.8, a few 8.2's being 8.3 and so on.
Code: Select all
1.7 1456
2.0 31165
2.5 1173
2.6 19633
2.8 1301
3.0 2857
3.2 3068
3.4 378
3.6 15
3.8 56
4.2 101278
4.4 6682
4.5 7002
4.6 1372
4.7 18
5.6 12372
5.7 2854
5.8 43
6.2 505
6.5 2157
6.6 102638
6.7 4603
6.8 4571
6.9 5057
7.0 3318
7.1 46282
7.2 12858
7.3 64
7.5 2
7.6 44
7.7 24
7.8 4
8.2 44
8.3 149
8.4 9

here is the distribution of top ratings by clue count. the top line refers to clue count in the converted 9x9s, the next line to the original 6x6s
Code: Select all
se\cl9 54     55     56     57     58     59     60     61     62     63     64     65
se\cl6 9      10     11     12     13     14     15     16     17     18     19     20     total
-------------------------------------------------------------------------------------------------
8.4                         8                           1                                  9
8.3           4      25     71     17     15     10     7                                  149
8.2                  42     2                                                              44
7.8                                4                                                       4
7.7                                3      7      12     2                                  24
7.6           2      4      14     12     10            2                                  44
7.5                  2                                                                     2
7.3                  34     8      18     4                                                64
7.2           110    1423   3459   3019   2295   1531   686    255    58     19            12858
7.1           374    5589   11268  10186  8677   5383   2846   1257   600    60     14     46282

and finally here are the nine SE 8.4's. the top one is the 16-clue and is a (non-minimal) diamond that solves in one step. the other 8 are 12-clue puzzles that have ED=3.0 but have a much longer solve path, and i wonder if they're all basically isomorphic. numbers 1 and 5-8 are new; the others were found in the previous batch by 1to9only twice each, as there are two places to get rid of an initial single in each one.
original 6x6 format:
Code: Select all
1...56...1..21...5.35..13.1.6..62.1.
....5.4....3...5.1...34.3.2.1..6..3.
.2......61..2.4...61.....4.6.5.6..3.
.2.4....6...2.4...61......2..5..123.
.....64...2.23...1..5..2...61....2.4
1....6....2..3..6.6.5.4....61....2.4
..3....5.1....456...5..234....5.1...
..34...5.....3..6..1.3.234....5.1...
1...5......3...5.1...34...2..556...4

converted 9x9s:
Code: Select all
8...19567...7..81919785623498...1725.15..79833729856417.1.6.398.68.9.172239178456
....8.9579....7834487953126...8.9571...37.4898795412637.8.9.312.6..3.798392718645
.8....927..97..8162671893459.8...47271....689624897153.7.6.8594.9..3.768846975231
.8.9..247..7...8969264871358.9...47267....981214879563..8..5729..279.318791238654
.....89679...7.82448792613583...2719..9..7582275891346...78.691...2.9478798614253
8....9167....7.892197826345.8..9.6737.9.6.458635748921...68.719...9.7284978214536
..8...937.9.7..815357189246..957.468..5..879287496215398....3747.1...589543897621
..89..347.7....895953487126.8..9.673.3.7.821971936245889....7345.7...981341879562
8...9.157.....7893197853246...9.8571...37.984978541632..9..572878...9465562784319

a summary of hardest high-clue puzzles has been posted to my "maximum clues for each se rating" thread.
i'm not sure what to do with the remaining 167205 non-convertibles. maybe i'll leave the task of re-rating the entire batch with se-modified-for-6x6s to 1to9only to work his magic :P
Once upon a time I was a teenager who was active on here 2007-2011
ocean and eleven should have paired up to make a sudoku-solving duo called Ocean's Eleven
999_Springs
 
Posts: 473
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

Re: hardest 6x6?

Postby qiuyanzhe » Wed Apr 24, 2019 9:49 am

999_Springs wrote:
Code: Select all
....5.4....3...5.1...34.3.2.1..6..3.
.2......61..2.4...61.....4.6.5.6..3.
.2.4....6...2.4...61......2..5..123.
.....64...2.23...1..5..2...61....2.4
1....6....2..3..6.6.5.4....61....2.4
..3....5.1....456...5..234....5.1...
..34...5.....3..6..1.3.234....5.1...
1...5......3...5.1...34...2..556...4

Yes, these 12-clue 8.4 puzzles are isomorphic.
qiuyanzhe
 
Posts: 78
Joined: 21 August 2017
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