giant sudokus

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Postby 1to9only » Thu Mar 10, 2022 11:46 am

philvo wrote:I rate this X-sudoku EXTREME-446.

This puzzle has been crossposted here: http://forum.enjoysudoku.com/sudoku16x16-x-t39847.html.
I'm not a fan of crossposting as it makes searching for info such a pain! So this puzzle is at least ED=12.9.
In the same ballpark as Blue's Ultimate 16x16s.
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Re: giant sudokus

Postby philvo » Mon Apr 25, 2022 11:18 am

Hello,
The 36x36 x-sudoku by hkociemba1 is SOLVED (see posts above) ! I knew that this grid was hard, but I did not expect a so incredible difficulty. This is the most difficult grid I have ever solved. With my own notation, it is rated over 4000 ! Has anyone rated this grid with the SExx notation ?
Congratulations to hkociemba1 for generating a so complex x-sudoku.
Phil
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Re: giant sudokus

Postby m_b_metcalf » Mon Apr 25, 2022 2:01 pm

philvo wrote:The 36x36 x-sudoku by hkociemba1 is SOLVED (see posts above) ! Il

Congratulations. What breakthrough did you make? How long did it take?

mike
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Re: giant sudokus

Postby urhegyi » Tue Apr 26, 2022 4:08 pm

I solved a 16x16 diagonal x-sudoku by hand in about 6 hours.
Curious to know the SE rating.
Code: Select all
ELPCGAD...K.I.H.
.GO...P..J......
.....CN.........
N...E...HI...GPK
...K...CLM..EJB.
.HA.L..G..D.F..C
.........HJ..LMG
....JN...G..KA..
..HL..E...MI....
CBN..OG.........
P..J.L..F..E.BC.
.FEA..MDB...L...
DCB...FM...J...N
.........OH.....
......A..F...OL.
.J.O.H...BADPFKI

solution:
Hidden Text: Show
Code: Select all
ELPCGADFONKBIMHJ
BGOHMIPKAJELCDNF
KMJIHCNODPFGBEAL
NADFEBJLHICMOGPK
GNIKDFOCLMPAEJBH
JHABLMKGIEDNFPOC
FPCDIEBAKHJONLMG
LOMEJNHPCGBFKAID
ODHLCJEBNAMIGKFP
CBNMFOGHJKLPDIEA
PKGJALINFDOEHBCM
IFEAKPMDBCGHLNJO
DCBPOKFMELIJAHGN
AEFNPGLIMOHKJCDB
HIKGBDAJPFNCMOLE
MJLONHCEGBADPFKI

If anyone can check this x-sudoku needs pointing/claiming and naked/hidden subsets(up to quad).
Image
Last edited by urhegyi on Tue Apr 26, 2022 4:35 pm, edited 1 time in total.
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Re: giant sudokus

Postby m_b_metcalf » Tue Apr 26, 2022 4:33 pm

urhegyi wrote:I solved a 16x16 diagonal x-sudoku by hand in about 6 hours.
Curious to know the SE rating.
My program needs pointing and also intersections, so that's SE 2.6 or 2.9.

Mike
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Re: giant sudokus

Postby philvo » Tue Apr 26, 2022 7:36 pm

Hello Mike,
For the 36 x-sudoku by hkociemba1, I use classic algorithms: X-wing, AIC, swordfish. And when they fail, I select the 'best' bi-value cell and continue on a next level solving the 2 sub-grids obtained with each value. And so on, until an error or a solution is found. For this extreme x-sudoku, I had to activate 24 levels and solve 5910 puzzles before obtaining a solution. And 37 levels & 7748 grids for full resolution and to confirm that this solution is unique. My solver is written in Excel. Since it's not the fastest language, my solver ran in cumulative time for 367 hours (!).
Thanks to hkociemba1 for this amazing grid. It was a very interesting challenge !
Phil
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Re: giant sudokus

Postby m_b_metcalf » Tue Apr 26, 2022 7:59 pm

m_b_metcalf wrote:
urhegyi wrote:I solved a 16x16 diagonal x-sudoku by hand in about 6 hours.
Curious to know the SE rating.
My program needs pointing and also intersections, so that's SE 2.6 or 2.9.

This version (with different numbering but otherwise the same with a few cells removed) is much harder:
Code: Select all
 14  .  8 12 16 10 13  .  .  .  9  .  2  .  1  .
  . 16  7  .  .  .  8  .  .  3  .  .  .  .  .  .
  .  .  .  .  . 12  6  .  .  .  .  .  .  .  .  .
  6  .  .  . 14  .  .  .  1  2  .  .  . 16  8  9
  .  .  .  9  .  .  . 12  4  5  .  . 14  3 11  .
  .  1 10  .  4  .  . 16  .  . 13  . 15  .  .  .
  .  .  .  .  .  .  .  .  .  .  .  .  .  4  5 16
  .  .  .  .  3  6  .  .  . 16  .  .  9 10  .  .
  .  .  1  4  .  . 14  .  .  .  5  2  .  .  .  .
 12 11  6  .  .  7 16  .  .  .  .  .  .  .  .  .
  8  .  .  3  .  4  .  . 15  .  . 14  . 11 12  .
  . 15 14 10  .  .  . 13 11  .  .  .  4  .  .  .
 13 12 11  .  .  . 15  5  .  .  .  3  .  .  .  6
  .  .  .  .  .  .  .  .  .  7  1  .  .  .  .  .
  .  .  .  .  .  . 10  .  . 15  .  .  .  7  4  .
  .  3  .  7  .  1  .  .  . 11 10 13  . 15  9  2
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Postby 1to9only » Fri Apr 29, 2022 7:45 am

The current 64x64 sudoku puzzle of the month at https://sudokugeant.cabanova.com is rated ED=3.0/1.2/1.2.

m_b_metcalf wrote:IMHO, this 36x36 X-sudoku, due to hkociemba1, is SE10+:

philvo wrote:With my own notation, it is rated over 4000 ! Has anyone rated this grid with the SExx notation ?

To start with, there are a number of singles and intersections. This reduces the number of candidates from 4681 to 3651. Enough to attempt a rating!
At candidates 3651, ED=3.6/1.2/1.2. After a number more solving steps, the rating is ED=12.9/1.2/1.2. The final rating is not yet available!

urhegyi wrote:I solved a 16x16 diagonal x-sudoku by hand in about 6 hours.
Curious to know the SE rating.

ED=2.6/1.2/1.2

m_b_metcalf wrote:This version (with different numbering but otherwise the same with a few cells removed) is much harder:

ED=10.1/1.2/1.2
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Postby 1to9only » Fri May 06, 2022 7:46 am

philvo wrote:By the way, my personal record is this 3-symmetry 16x16 X-sudoku that I have generated some years ago.
I rate this X-sudoku EXTREME-446.

. . . . 16 12 . . . . 7 3 . . . .
. . . . . 2 . 7 4 . 11 . . . . .
. . . 6 11 1 15 10 9 5 2 8 14 . . .
. . 1 . . . . 3 6 . . . . 7 . .
10 . 9 . . . . 12 5 . . . . 4 . 2
8 14 3 . . . . 2 1 . . . . 13 5 7
. . 4 . . . . . . . . . . 16 . .
. 6 16 5 3 13 . . . . 8 14 1 11 12 .
. 2 5 13 9 11 . . . . 1 16 8 15 4 .
. . 8 . . . . . . . . . . 12 . .
1 12 10 . . . . 6 14 . . . . 5 9 11
3 . 11 . . . . 1 8 . . . . 2 . 13
. . 14 . . . . 5 3 . . . . 8 . .
. . . 9 14 7 2 11 16 10 13 1 4 . . .
. . . . . 9 . 16 2 . 14 . . . . .
. . . . 12 4 . . . . 5 6 . . . .


ED=12.9/1.5/1.5
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Re: giant sudokus

Postby urhegyi » Mon May 09, 2022 7:54 pm

Another 16x16 sudoku-X.
Curious about it's rating.
Code: Select all
+-------------+-------------+-------------+-------------+
 |  1  .  .  4 |  .  .  .  . |  . 10  .  . | 13 14  .  . |
 |  .  .  .  . |  9  .  . 12 |  .  .  .  . |  .  2  3  . |
 |  9  .  .  . | 14  . 15  . |  .  2  .  . |  6  .  .  . |
 | 13  .  . 15 |  .  2  .  4 |  .  .  .  7 |  9  . 11 12 |
 +-------------+-------------+-------------+-------------+
 |  2  1  .  . |  .  .  8  6 |  .  .  .  . |  .  .  . 15 |
 |  .  6  8  . | 10  .  9  . |  .  .  .  . |  .  .  4  3 |
 | 10  .  .  . |  . 16 13  . |  .  .  .  3 |  .  .  7  . |
 |  .  .  .  . |  .  .  4  . |  5  8  7  . |  .  . 12 11 |
 +-------------+-------------+-------------+-------------+
 |  3  .  .  . |  .  .  .  . |  . 12  9 11 |  . 16  .  . |
 |  .  .  .  6 | 11  9  . 10 |  .  .  . 15 |  .  .  .  . |
 |  . 12  .  . |  .  .  . 15 |  3  .  .  . |  .  5  .  . |
 | 16  . 13  . |  .  .  .  3 |  .  .  .  . |  .  .  .  . |
 +-------------+-------------+-------------+-------------+
 |  .  .  2  . |  8  .  6  . | 12  .  .  9 | 16  .  . 13 |
 |  8  .  .  . |  . 11 10  . | 16  .  . 13 |  .  .  .  1 |
 |  .  . 10  . |  . 15 14  . |  4  .  2  . |  8  .  .  . |
 |  .  . 14 13 |  .  .  .  . |  .  .  6  . | 12  .  .  . |
 +-------------+-------------+-------------+-------------+
diagonal sudoku
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Re: giant sudokus

Postby philvo » Sat May 14, 2022 3:27 pm

Hello urhegyi,
Very interesting X-sudoku. It is one of the hardest I have seen. My solver rates it EXTREME-106.
If you want, you can download the X-sudoku solver on http://sudokugeant.cabanova.com
I also noticed that this grid is very regular : the same groups of 4 numbers are aligned in every box. We can roughly guess it in the initial grid.
With this hypothesis, you can find easily a solution, but it is more difficult to prove that this solution is unique.
phil
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Postby 1to9only » Sun May 15, 2022 10:42 am

philvo wrote:I also noticed that this grid is very regular : the same groups of 4 numbers are aligned in every box. We can roughly guess it in the initial grid.

I think this was created using hkociemba's sudokuNxM program from here; hkociemba first posted about here.
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Re: giant sudokus

Postby philvo » Mon Jun 27, 2022 3:19 pm

Hi,
I submit this symmetric 16x16 X-sudoku. My solver ( http://sudokugeant.cabanova.com ) rates it EXTREME - 106, one of the hardest I have generated.

. . . 4 8 10 1 . . 16 7 6 12 . . . . 16 6 10 13 . . . . . . 3 15 4 9 . . . 15 . 2 . . . . . . 12 . 5 . . 13 . . 3 16 . . . . . . 14 1 . . 7 . 9 . . . . 16 . . 14 . . . . 1 . 8 . 7 . 10 . . . . . . 5 . 2 . 15 . . . . . 13 . . . . 11 . . . . . . . . . 4 6 11 . . 13 9 2 . . . . . . 12 . . 16 . . . . 8 . . 13 . . 1 . 2 . . . . . . . . . . 3 . 8 6 11 . 9 . . . . . . . . 4 . 12 1 . 4 . . . . 8 . . 2 . . . . 16 . . 12 16 . . . . . . . . . . 14 2 . . 10 . 7 . . . 16 12 . . . 5 . 8 . 11 2 . . . . . 5 1 . . . . . 4 9 . 3 . . 9 . 13 6 2 8 . 10 . . 15 .

I will be interested if somebody can rate this X-sudoku with the SExx notation (that I do not master).
Thanks very much.
Phil
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Re: giant sudokus

Postby urhegyi » Tue Jun 28, 2022 7:11 am

philvo wrote:Hi,
I submit this symmetric 16x16 X-sudoku. My solver ( http://sudokugeant.cabanova.com ) rates it EXTREME - 106, one of the hardest I have generated.

. . . 4 8 10 1 . . 16 7 6 12 . . . . 16 6 10 13 . . . . . . 3 15 4 9 . . . 15 . 2 . . . . . . 12 . 5 . . 13 . . 3 16 . . . . . . 14 1 . . 7 . 9 . . . . 16 . . 14 . . . . 1 . 8 . 7 . 10 . . . . . . 5 . 2 . 15 . . . . . 13 . . . . 11 . . . . . . . . . 4 6 11 . . 13 9 2 . . . . . . 12 . . 16 . . . . 8 . . 13 . . 1 . 2 . . . . . . . . . . 3 . 8 6 11 . 9 . . . . . . . . 4 . 12 1 . 4 . . . . 8 . . 2 . . . . 16 . . 12 16 . . . . . . . . . . 14 2 . . 10 . 7 . . . 16 12 . . . 5 . 8 . 11 2 . . . . . 5 1 . . . . . 4 9 . 3 . . 9 . 13 6 2 8 . 10 . . 15 .

I will be interested if somebody can rate this X-sudoku with the SExx notation (that I do not master).
Thanks very much.
Phil

Code: Select all
  .  .  .  4  8 10  1  .  . 16  7  6 12  .  .  .
  . 16  6 10 13  .  .  .  .  .  .  3 15  4  9  .
  .  . 15  .  2  .  .  .  .  .  . 12  .  5  .  .
 13  .  .  3 16  .  .  .  .  .  . 14  1  .  .  7
  .  9  .  .  .  . 16  .  . 14  .  .  .  .  1  .
  8  .  7  . 10  .  .  .  .  .  .  5  .  2  . 15
  .  .  .  .  . 13  .  .  .  . 11  .  .  .  .  .
  .  .  .  .  4  6 11  .  . 13  9  2  .  .  .  .
  .  . 12  .  . 16  .  .  .  .  8  .  . 13  .  .
  1  .  2  .  .  .  .  .  .  .  .  .  .  3  .  8
  6 11  .  9  .  .  .  .  .  .  .  .  4  . 12  1
  .  4  .  .  .  .  8  .  .  2  .  .  .  . 16  .
  . 12 16  .  .  .  .  .  .  .  .  .  . 14  2  .
  . 10  .  7  .  .  . 16 12  .  .  .  5  .  8  .
 11  2  .  .  .  .  .  5  1  .  .  .  .  .  4  9
  .  3  .  .  9  . 13  6  2  8  . 10  .  . 15  .
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