The New Sudoku Players' Forum

[enxio27]

I know that vanilla gattai are not the usual fare for most of you, but I'm hoping at least one of you will take a look at this one. Am I mistaken, or does this puzzle have more than one solution? Richard Broughton's Sudoku Solver's validity function apparently checks for *a* solution, but not for multiple solutions. I was able to solve all but grids 4, 5, and 7, as was Sudoku Solver.

Code: Select all

9...7.6.5.86.........6.....5....8.1.2.8..5.934.193......45.7........9......1.....
2..85...4.....7......9.1...6.......9.59...76.........3..........1..32........9...
.....9.3....18........2.8.....2.....3.2.5..4..143...25...87.......9..........1...
..8......75.642.1.6....9....19.635.2..7..4.6..6215..9..2.3.....87..1.............
...8...................2........1.453.......8.1.7.62.......8...............1.....
...8..2........6.....9.7..6.8.2.57....9......7...3....6...2.8.....1.3..2...7....4
....1................3.....7.21.3..91..5.8....6....1.............79......2.6.....
...2.86...............9......17.....4...697.3.....3.5.....8.......3...72...95..3.
............47.......3.....1.....7.42..74...8....6859.7.........2.9.54..8......3.


[eleven]

Yes, its annoying, the puzzle has multiple solutions.
Though i cannot be sure that i made everything correct (i started 3 times manually, then doublechecked with a vanilla solver), it looks so.
In the grid for puzzle 4 you can see a typical deadly pattern with 2 solutions. Box 9 is box 1 of puzzle 7, but it is not resolved there either.

Code: Select all

4
+-------------+-------------+-------------+
| 2   9   8   | 5   3   1   | 7   4   6   |
| 7   5   3   | 6   4   2   | 9   1   8   |
| 6   4   1   | 8   7   9   | 3   2   5   |
+-------------+-------------+-------------+
| 4   1   9   | 7   6   3   | 5   8   2   |
| 5   8   7   | 9   2   4   | 1   6   3   |
| 3   6   2   | 1   5   8   | 4   9   7   |
+-------------+-------------+-------------+
| 1   2   6   | 3   9   7   | 8   5   4   |
| 8   7   45  | 24  1   56  | 26  3   9   |
| 9   3   45  | 24  8   56  | 26  7   1   |
+-------------+-------------+-------------+
5
+-------------------+-------------------+-------------------+
| 9     3     2     | 8     1     7     | 4     5     6     |
| 5     7     6     | 49    349   349   | 8     2     1     |
| 1     4     8     | 5     6     2     | 9     7     3     |
+-------------------+-------------------+-------------------+
| 26    26    9     | 3     8     1     | 7     4     5     |
| 3     5     7     | 249   249   49    | 1     6     8     |
| 8     1     4     | 7     5     6     | 2     3     9     |
+-------------------+-------------------+-------------------+
| 267   269   3     | 269   279   8     | 5     1     4     |
| 467   8     1     | 46    47    5     | 3     9     2     |
| 24    29    5     | 1     2349  349   | 6     8     7     |
+-------------------+-------------------+-------------------+
7
+-------------------+-------------------+-------------------+
| 8     5     4     | 27    1     269   | 267   269   3     |
| 26    3     9     | 247   25    2456  | 467   8     1     |
| 26    7     1     | 3     8     2469  | 24    29    5     |
+-------------------+-------------------+-------------------+
| 7     4     2     | 1     6     3     | 8     5     9     |
| 1     9     3     | 5     7     8     | 26    26    4     |
| 5     6     8     | 24    9     24    | 1     3     7     |
+-------------------+-------------------+-------------------+
| 9     1     6     | 8     3     7     | 5     4     2     |
| 4     8     7     | 9     25    25    | 3     1     6     |
| 3     2     5     | 6     4     1     | 9     7     8     |
+-------------------+-------------------+-------------------+

[enxio27]

Thank you, eleven! It is as I suspected. You got to the same point I did and that Richard Broughton's Sudoku Solver did.

This is disappointing. The way the Web site is set up, you have to complete one puzzle before you are allowed to even see the next one. And it's all in French (which I don't speak/write).

[enxio27]

Apparently they figured out that the puzzle was invalid and revised it. Updated puzzle (which I completed last week):

Code: Select all

9...7.6.5.86.........6.....5....8.1.2.8..5.934.193.......5.7......489......1.....
2..85.........7......9.1...6.......9.59...76.........3.............32........9...
.....9.3....18........2.8.....2.....3.2.5..4..143...25...87.......9..........1...
..8......75.642...6....9....19.635.2..7..4.6..6215..9..2.3.....87..1.............
...8...................2........1.453.......8.1.7.62.......8...............1.....
...8..2........5.....9.7..6.8.2.57....9......7...3........2.8.....1.3..2...7....4
....1................3.2...7.21.3..91..5.8.6..6....1.......7.....79......2.6.....
...2.8................9......17.....4...697.3.....3.5.....8.......3...72...95..3.
.....6......47.......35....1.....7.42..74...8....6859.7.........2.9.54..89.....3.


FWIW, the sudoku puzzles on that site come from vfalcone.ru. Jeux.kevicar.com has dropped the sudoku section from their updated site (something about not being able to run the sudoku part under phpBB3).