Triple Sudoku

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Triple Sudoku

Postby kakuroatk » Sat Dec 11, 2021 12:36 am

Here is a triple sudoku that encompasses 3 - 9x9 overlapping sudokus:

Image

This puzzle can be playable online here: https://www.atksolutions.com/games/sudoku.html
and the puzzle # is M90516 which can be entered by clicking the pencil/paper icon on the main screen.

This puzzle may have some unique strategies due to the symmetry.

It is a medium level puzzle.
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Re: Triple Sudoku

Postby m_b_metcalf » Sat Dec 11, 2021 10:46 am

Here's your puzzle in text form. It's not too hard, but has 11 redundant clues. By removing, for instance, r8c1 and r12c5, you obtain a very hard, minimal puzzle.
Code: Select all
 . . 7 5 . . . 6 . . . . . . .
 4 . . . . . . . 9 . . . . . .
 5 2 . . . . 3 . . . . . . . .
 . 3 . 7 . . 1 . . . 5 . . . .
 . . . . . 1 . . . . . . . . .
 . . . . 5 . 8 . . . . . . . .
 . . 8 . . . 9 . . 8 . . . . .
 3 . . 8 . . . . . . . 3 . . 2
 . . . . . 9 . . 4 . . . 1 . .
 . . . . . . . . 9 . 3 . . . .
 . . . . . . . . . 2 . . . . .
 . . . . 9 . . . 7 . . 4 . 5 .
 . . . . . . . . 6 . . . . 8 7
 . . . . . . 8 . . . . . . . 9
 . . . . . . . 9 . . . 7 5 . .

The solution:
Hidden Text: Show
Code: Select all
 9 1 7 5 2 3 4 6 8 . . . . . .
 4 8 3 1 6 7 5 2 9 . . . . . .
 5 2 6 4 9 8 3 1 7 . . . . . .
 2 3 5 7 8 4 1 9 6 3 5 2 . . .
 8 6 4 9 3 1 2 7 5 4 8 6 . . .
 7 9 1 2 5 6 8 4 3 9 1 7 . . .
 1 4 8 6 7 5 9 3 2 8 4 1 7 6 5
 3 7 9 8 4 2 6 5 1 7 9 3 8 4 2
 6 5 2 3 1 9 7 8 4 6 2 5 1 9 3
 . . . 1 2 7 4 6 9 5 3 8 2 7 1
 . . . 4 6 3 5 1 8 2 7 9 6 3 4
 . . . 5 9 8 3 2 7 1 6 4 9 5 8
 . . . . . . 1 4 6 9 5 2 3 8 7
 . . . . . . 8 7 5 3 1 6 4 2 9
 . . . . . . 2 9 3 4 8 7 5 1 6


Regards,

Mike
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Re: Triple Sudoku

Postby m_b_metcalf » Sun Dec 12, 2021 11:06 am

Seems to me that, in these puzzles, the central box, common to all three sub-puzzles, should be empty. Here's a not-quite minimal but symmetric and human-solvable example:

Code: Select all
 . . . . . . 9 . . . . . . . .
 . 2 8 . . 1 . . . . . . . . .
 . 7 . 5 . . . . . . . . . . .
 5 . . 3 . . . . . 9 . . . . .
 8 . . . 7 . 3 . 9 8 . . . . .
 . . 2 . . . . 8 . . . . . . .
 6 . . . 8 . . . . . . 7 . . .
 . . . . 3 . . . . . 9 . . . .
 . . . 4 . . . . . . 2 . . . 7
 . . . . . . . 3 . . . . 1 . .
 . . . . . 9 6 . 8 . 3 . . . 2
 . . . . . 3 . . . . . 6 . . 3
 . . . . . . . . . . . 1 . 6 .
 . . . . . . . . . 3 . . 2 8 .
 . . . . . . . . 7 . . . . . .
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Re: Triple Sudoku

Postby Hajime » Sun Dec 12, 2021 5:04 pm

Remembers me of my "name"-puzzle some 3 years ago
http://forum.enjoysudoku.com/post267510.html?hilit=Name#p267510
It is still my avatar at this moment ;)
Only it is using 5 sudoku's instead of 3.
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Re: Triple Sudoku

Postby kakuroatk » Sun Dec 12, 2021 6:36 pm

Hi m_b_metcalf, that one I rate as a Easy/Medium ... Solution:

Hidden Text: Show
Code: Select all
 1 6 5 8 2 3 9 7 4 . . . . . .
 9 2 8 7 4 1 6 3 5 . . . . . .
 3 7 4 5 6 9 2 1 8 . . . . . .
 5 9 6 3 1 8 4 2 7 9 6 5 . . .
 8 4 1 2 7 5 3 6 9 8 4 1 . . .
 7 3 2 6 9 4 5 8 1 3 7 2 . . .
 6 5 7 9 8 2 1 4 3 6 5 7 9 2 8
 4 8 9 1 3 6 7 5 2 4 9 8 6 3 1
 2 1 3 4 5 7 8 9 6 1 2 3 4 5 7
 . . . 7 6 1 2 3 4 5 8 9 1 7 6
 . . . 5 2 9 6 1 8 7 3 4 5 9 2
 . . . 8 4 3 9 7 5 2 1 6 8 4 3
 . . . . . . 3 2 9 8 4 1 7 6 5
 . . . . . . 4 6 1 3 7 5 2 8 9
 . . . . . . 5 8 7 9 6 2 3 1 4


Hi Hajime,

Remembers me of my "name"-puzzle some 3 years ago
post267510.html?hilit=Name#p267510
It is still my avatar at this moment ;)
Only it is using 5 sudoku's instead of 3.


I like that named one! Very nice. I assume you needed to set the fixed values to match your name pattern and then generated a puzzle from there.
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tripledoku4 ratings

Postby 1to9only » Tue Dec 14, 2021 10:34 am

SE ratings for the 2 tripledoku4 puzzles:
triple= 3 sudokus
4= 4 nonets overlap for 2 adjacent sudokus

Code: Select all
..75...6.4.......952....3...3.7..1.......1.......5.8....8...9..3..8..........9..4 ED=3.0/1.2/1.2
7..1...5...1.......5.8........9..8..8.......3..9..4........9.3.......2...9...7..4 ED=3.4/1.2/1.2
9..8..........3..2..4...1....9.3.......2.......7..4.5...6....878.......9.9...75.. ED=1.5/1.2/1.2
ED=3.4/1.2/1.2

Code: Select all
......9...28..1....7.5.....5..3.....8...7.3.9..2....8.6...8........3.......4..... ED=2.8/1.2/1.2
3.....9...7.3.98......8.....8......7.3.....9.4......2.....3......96.8.3...3.....6 ED=2.8/1.2/1.2
.....7.......9........2...7.3....1..6.8.3...2.....6..3.....1.6....3..28...7...... ED=2.8/1.2/1.2
ED=2.8/1.2/1.2
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Re: Triple Sudoku

Postby m_b_metcalf » Tue Dec 14, 2021 12:28 pm

Could I ask you to try the first of these with r8c1 and r12c5 removed? Thanks. M
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Re: Triple Sudoku

Postby 1to9only » Tue Dec 14, 2021 1:01 pm

m_b_metcalf wrote:Could I ask you to try the first of these with r8c1 and r12c5 removed? Thanks. M

Code: Select all
..75...6.4.......952....3...3.7..1.......1.......5.8....8...9.....8..........9..4 ED=9.0/1.2/1.2
7..1...5...1.......5.8........9..8..8.......3..9..4........9.3.......2.......7..4 ED=9.3/1.2/1.2
9..8..........3..2..4...1....9.3.......2.......7..4.5...6....878.......9.9...75.. ED=9.2/1.2/1.2
ED=9.3/1.2/1.2
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Re: Triple Sudoku

Postby m_b_metcalf » Tue Dec 14, 2021 1:17 pm

Confirms my result. Thanks.
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