FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in          Games  Calendar Log in to check your private messages    So I thought it wasn't possible...          Sudoku Programmers Forum Index -> Solving sudoku View previous topic :: View next topic   Author Message tilps Joined: 19 Jun 2005 Posts: 44 : Items Posted: Sun Jul 24, 2005 10:47 pm    Post subject: So I thought it wasn't possible... Code: ...|.7.|.9. ...|..8|..4 .42|..1|.7. ---+---+--- ..4|...|..8 8..|2.5|..9 5..|...|7.. ---+---+--- .7.|6..|13. 2..|8..|... .6.|.3.|... But this puzzle was rated a 2. How goes other peoples solvers with this challenging puzzle? Back to top Michael Kennett Joined: 21 Jul 2005 Posts: 11 : Location: Adelaide, South Australia Items Posted: Mon Jul 25, 2005 3:04 am    Post subject: Re: So I thought it wasn't possible... tilps wrote: How goes other peoples solvers with this challenging puzzle? I get the following solution history (c.f.: the solver) Code: D:\foo\sudoku-1.0.1>sudoku -dv tilps.txt Solution(s) to 'tilps 24/July/2005' [fiendish] % tilps 24/July/2005 << solved board omitted >> Solution history: 8 -> (1,2), 8 -> (3,7), 7 -> (5,3), 8 -> (6,5), 8 -> (7,3), 8 -> (9,8) 7 -> (2,1), 2 *> (7,9), 2 -> (2,5), 5 -> (7,5), 2 -> (9,6), 2 -> (1,7) 3 *> (5,2), 3 -> (8,3), 9 *> (7,6), 4 -> (7,1), 7 *> (8,6), 7 -> (4,4) 7 -> (9,9), 6 *> (3,5), 9 -> (4,5), 4 *> (5,5), 1 -> (5,8), 6 -> (5,7) 1 -> (8,5), 1 -> (6,4), 4 -> (6,8), 4 -> (1,6), 4 -> (9,4), 1 -> (1,9) 2 -> (6,2), 3 -> (6,9), 2 -> (4,8), 4 -> (8,7), 1 -> (4,2), 5 -> (3,9) 3 -> (2,7), 6 -> (2,8), 3 -> (4,6), 5 -> (4,7), 9 -> (6,3), 6 -> (6,6) 9 -> (9,7), 9 -> (8,2), 6 -> (8,9), 1 -> (9,1), 6 -> (4,1), 9 -> (3,1) 1 -> (2,3), 5 -> (2,2), 9 -> (2,4), 6 -> (1,3), 5 -> (9,3), 5 -> (8,8) 3 -> (1,1), 5 -> (1,4), 3 -> (3,4) Firstly, I rate your board as fiendish - and this certainly shows in the solution history. The eighth move [2*>(7,9)] requires a choice (that's what the '*' means), and is followed 5 further choices. Does your solver need to make any arbitrary choices? Here are 4 (partially completed) boards where the first move my solver makes is an arbitrary choice - again, does your solver need to make any arbitrary choices? I've stared at these boards for far too long, and cannot see any moves not requiring choice - are any possible? Code: . . 7 | . . 9 | . 8 . 9 . 6 | 7 4 . | . 1 5 4 . 2 | 5 1 . | . . . ------+-------+------ 6 . 5 | . 7 . | . . 8 . 7 4 | . . . | . 3 . 8 . 3 | . . . | 7 . 6 ------+-------+------ . . . | . 6 7 | 8 . . 7 4 . | . 5 . | 9 6 2 . 6 . | 4 . . | . . . . . 8 | 2 . . | 4 . . . 9 4 | . 7 1 | 3 5 . . 1 . | . 4 . | . . 6 ------+-------+------ 4 . 1 | . . 7 | . 2 3 . 2 . | . 3 . | . . . . 8 . | 1 2 . | . . 4 ------+-------+------ 5 4 9 | . 1 . | 6 8 . 1 7 6 | . 8 . | . 3 . 8 3 2 | . . 5 | 1 4 . . . 6 | 9 8 4 | . 3 . 8 . 3 | 6 . 7 | 9 2 4 4 . 9 | 3 . 2 | 6 8 . ------+-------+------ 5 9 8 | 7 3 1 | 4 6 2 3 4 1 | 2 9 6 | . 7 . . . 2 | 8 4 5 | 3 1 9 ------+-------+------ . 8 . | 4 . 3 | . . 6 . . . | 5 . . | . . 3 . 3 . | 1 6 . | 2 . . 2 . . | . 8 4 | 5 1 6 1 . 6 | . . . | 8 3 4 . 8 . | . . 6 | 2 7 9 ------+-------+------ . . . | . . . | . 6 1 6 2 . | 4 . 9 | 3 8 5 8 5 . | . . . | . 2 7 ------+-------+------ 9 1 2 | 5 . . | 6 4 8 . . . | . . . | 7 . 2 . . 8 | . 4 2 | 1 . 3 Back to top tilps Joined: 19 Jun 2005 Posts: 44 : Items Posted: Mon Jul 25, 2005 10:37 am    Post subject: Re: So I thought it wasn't possible... Code: . . 7 | . . 9 | . 8 . 9 . 6 | 7 4 . | . 1 5 4 . 2 | 5 1 . | . . . ------+-------+------ 6 . 5 | . 7 . | . . 8 . 7 4 | . . . | . 3 . 8 . 3 | . . . | 7 . 6 ------+-------+------ . . . | . 6 7 | 8 . . 7 4 . | . 5 . | 9 6 2 . 6 . | 4 . . | . . . 1.0.2 - this is definitely within the realms of human logic solving. Code: . . 8 | 2 . . | 4 . . . 9 4 | . 7 1 | 3 5 . . 1 . | . 4 . | . . 6 ------+-------+------ 4 . 1 | . . 7 | . 2 3 . 2 . | . 3 . | . . . . 8 . | 1 2 . | . . 4 ------+-------+------ 5 4 9 | . 1 . | 6 8 . 1 7 6 | . 8 . | . 3 . 8 3 2 | . . 5 | 1 4 . 1.1.2 Code: . . 6 | 9 8 4 | . 3 . 8 . 3 | 6 . 7 | 9 2 4 4 . 9 | 3 . 2 | 6 8 . ------+-------+------ 5 9 8 | 7 3 1 | 4 6 2 3 4 1 | 2 9 6 | . 7 . . . 2 | 8 4 5 | 3 1 9 ------+-------+------ . 8 . | 4 . 3 | . . 6 . . . | 5 . . | . . 3 . 3 . | 1 6 . | 2 . . 1.0.3 - also easy Code: 2 . . | . 8 4 | 5 1 6 1 . 6 | . . . | 8 3 4 . 8 . | . . 6 | 2 7 9 ------+-------+------ . . . | . . . | . 6 1 6 2 . | 4 . 9 | 3 8 5 8 5 . | . . . | . 2 7 ------+-------+------ 9 1 2 | 5 . . | 6 4 8 . . . | . . . | 7 . 2 . . 8 | . 4 2 | 1 . 3 1.1.2 All of these puzzles look to be within the realms of human solution using basic logic rules... I havent verified that the 1.1.2's arent very hard by hand though. Back to top Nick70 Joined: 08 Jun 2005 Posts: 160 : Items Posted: Mon Jul 25, 2005 1:10 pm    Post subject: Puzzles 1 and 3 are solved iwth notiing more than single sector candidates. Puzzles 2 and 4 with nothing more than hidden pairs. Back to top darq Joined: 29 Jul 2005 Posts: 7 : Items Posted: Fri Jul 29, 2005 11:19 pm    Post subject: If puzzle 1 can be solved without x wings, what is the first step? 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