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| Spok
| | Joined: 03 Jan 2006 | | Posts: 8 | | : | | Location: London |
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 Posted: Wed Feb 22, 2006 9:47 pm Post subject: A problem with Simple Sudoku 4.1z |
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I am using version 4.1z and have come across a problem which someone may be able to help with.
I entered the following puzzle:
+---+---+---+
|53.|...|.26|
|..9|6.8|5..|
|..2|...|8..|
+---+---+---+
|6..|5.1|..8|
|...|...|...|
|4..|2.9|..7|
+---+---+---+
|..6|...|7..|
|..4|8.6|9..|
|95.|...|.81|
+---+---+---+
I am new to Sudoku and wanted the program to help me solve this puzzle. I began hitting F11 to step through the solving process and to read the hints on the Status Bar at the bottom.
On the 27th press of F11 I get 'No hint available' in the Status Bar, and the solving process halts. As far as I know, this puzzle has only one solution and can be solved using logic alone.
Does 'No hint available' mean that the puzzle cannot be solved? If this is the case the program should say so, perhaps explaining why in the Status Bar.
Here is another puzzle where the same thing happens, this time on the 32nd press of F11.
+---+---+---+
|3.7|6.4|8..|
|.6.|...|...|
|9..|..8|..6|
+---+---+---+
|...|5.7|9..|
|8.9|...|2.5|
|..1|2.3|...|
+---+---+---+
|6..|8..|..9|
|...|...|.5.|
|..2|7.6|1.3|
+---+---+---+
Does anyone know what is going on here?
Thanks,
Spok. |
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| Ruud
Site Admin
 | | Joined: 17 Sep 2005 | | Posts: 708 | | : | | Location: Netherlands |
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| Posted: Wed Feb 22, 2006 10:20 pm Post subject: |
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Hi Spok,
the first of these 2 sudokus can be solved with a Uniqueness Test type 1. An alternative to the Uniqueness Test is Forcing Chains or Tabling, which is also required for the second sudoku you posted.
These techniques are not implemented in Simple Sudoku.
If you want to solve these sudokus, be warned that you're in the "extreme" territory. You can use programs like Sudo Cue, Sudoku Susser and IntoSudoku to help you with these.
Ruud.
_________________
Meet me at sudocue.net |
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| angusj
Site Admin
 | | Joined: 18 Jun 2005 | | Posts: 406 | | : | |
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| Posted: Thu Feb 23, 2006 12:13 am Post subject: Re: A problem with Simple Sudoku 4.1z |
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| Spok wrote: | | Does 'No hint available' mean that the puzzle cannot be solved? If this is the case the program should say so, perhaps explaining why in the Status Bar. |
No, if the puzzle can't be solved Simple Sudoku will tell you it's an invalid puzzle.
There are some extreme solving techniques that I've chosen not to implement in Simple Sudoku (some because I think they require unreasonable assumptions, others because I think they're too obscure for mere mortals). So "No hint available" simply means "No hint available" and you're on your own to figure out the solution. |
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| Spok
| | Joined: 03 Jan 2006 | | Posts: 8 | | : | | Location: London |
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| Posted: Thu Feb 23, 2006 11:39 am Post subject: |
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Do Uniqueness Test type 1, (is there a type 2 and 3?), Forcing Chains and Tabling still constitute solving by logic, or are they regarded as 'Trial & Error'? If it's the former, then the puzzles that require these techniques are valid (providing there is still only one solution)
Perhaps Angus could incorporate these solving methods into another 'Extra Extreme' level, above 'Extreme'. We could then choose this level if we fancied a challenge  , while mere mortals could stck to the lower levels.
Thanks for your help,
Spok. |
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| angusj
Site Admin
| | Joined: 18 Jun 2005 | | Posts: 406 | | : | |
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| Posted: Thu Feb 23, 2006 12:30 pm Post subject: |
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| Spok wrote: | | Do Uniqueness Test type 1, (is there a type 2 and 3?), Forcing Chains and Tabling still constitute solving by logic, or are they regarded as 'Trial & Error'? If it's the former, then the puzzles that require these techniques are valid (providing there is still only one solution) |
None of the techniques you've mentioned involve 'Trial & Error'. However, if a puzzle did require T & E that wouldn't make the puzzle invalid just as T & E is not invalid.
| Spok wrote: | | Perhaps Angus could incorporate these solving methods into another 'Extra Extreme' level, above 'Extreme'. |
That's most unlikely. Sorry. |
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