Sudoku Extreme Volume 1 solutions not unique

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Sudoku Extreme Volume 1 solutions not unique

Postby ghfick » Thu May 04, 2017 4:39 pm

I must pass along a concern about a recently published book of puzzles. The book is called 'Sudoku Extreme Volume 1' by AD Ardson. I tried the very first puzzle in this book and I did not get very far. While labeled 'extreme', I became suspicious and so checked the solution count using Andrew Stuart's solver site. The puzzle does not have a unique solution. I have now checked the next 5 puzzles and all fail to have a unique solution. Ardson has published many books of puzzles but this is the first one to receive my attention. I have left a message of concern on his website and his email but so far I have not received a response. Clearly, the 'solutions' in the back of this book offer just one of the many possible 'solutions'. Here are the first 6:

.4.2..3...93......2..1...45.....56.2..28.14..8.56.....62...3..4......27...1..2.3.
....7.8.69..5..4....7....35...43...262.....491...92...37....6....6..9..32.5.4....
....362..6.8..4..9..9....4.5..78....1.4...7.3....41..8.4....8..8..4..1.7..219....
..2..3.7...5.6..2.1...27..8..7..56...6.....9..4.6..5..7..35...6.5..1.2...3.4..7..
.8......61..64.5...57..3....7..9..68...8.4...81..5..9....9..62...9.32..12......5.
.46....9.5...6........846.562.....5...46721...7.....641.572........1...2.3....51.

Best
Gordon
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Re: Sudoku Extreme Volume 1 solutions not unique

Postby dobrichev » Thu May 04, 2017 6:42 pm

Hi ghfick,

I am confirming that the puzzles you posted if follow the traditional rules have multiple solutions.
Code: Select all
.4.2..3...93......2..1...45.....56.2..28.14..8.56.....62...3..4......27...1..2.3.   28   18
....7.8.69..5..4....7....35...43...262.....491...92...37....6....6..9..32.5.4....   28   47
....362..6.8..4..9..9....4.5..78....1.4...7.3....41..8.4....8..8..4..1.7..219....   28   43
..2..3.7...5.6..2.1...27..8..7..56...6.....9..4.6..5..7..35...6.5..1.2...3.4..7..   28   21
.8......61..64.5...57..3....7..9..68...8.4...81..5..9....9..62...9.32..12......5.   28   9
.46....9.5...6........846.562.....5...46721...7.....641.572........1...2.3....51.   29   427

I don't know what 'Sudoku Extreme Volume 1' is.
Seems that either the author goofed, or there are additional constraints for these puzzles which you neglected.

If you are sure there are no additional rules and it is entirely authors goof, you may copy these along with a link to the publication in the dedicated thread http://forum.enjoysudoku.com/sudokus-of-shame-t3071.html.
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Re: Sudoku Extreme Volume 1 solutions not unique

Postby Botchee » Thu Apr 16, 2020 9:19 am

Unique solutions were why I took down tophatpuzzle.com, but since have learned how to do my own programming, to create a sliding puzzle with its unique shape. I've finally escaped my code cave, but the world has gone whacky with this Covid-19 thing!

:oops: <-- dude's running a fever <-- :lol:
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Re: Sudoku Extreme Volume 1 solutions not unique

Postby m_b_metcalf » Thu Apr 16, 2020 10:17 am

I took another look at these puzzles. The first 5 of the 6 'solve' with a simple backdoor. Maybe the sixth can be 'solved' by a less simple backdoor.

Could it be that the puzzles were generated using a backdoor technique, among others, something that should not be done?

Mike
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