FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in          Games  Calendar Log in to check your private messages    TheTimes - Sat 22 Oct 2005 - Su doku for all - Samurai 45min          Sudoku Programmers Forum Index -> Exotic sudoku View previous topic :: View next topic   Author Message kranser Joined: 18 Aug 2005 Posts: 35 : Items Posted: Sun Oct 23, 2005 7:49 pm    Post subject: TheTimes - Sat 22 Oct 2005 - Su doku for all - Samurai 45min Has anyone managed to solve the UK Times Newspaper - Sat 22 Oct 2005 - Su doku for all booklet - Samurai 45min puzzle? It doesn't seem to be solveable! Here is the pic: http://images.thetimes.co.uk/TGD/picture/0,,238060,00.jpg And here is the text version for anyone with solvers: Code: . . . ¦ 4 8 . ¦ . . 6 . . . ¦ . . . ¦ . . . . . 4 ¦ . . 9 ¦ 2 . . ------+-------+------- 7 . . ¦ . 5 . ¦ . . . 8 . . ¦ 1 2 . ¦ . 3 5 . . 6 ¦ . . . ¦ . . . ------+-------+------- . . 3 ¦ . . . ¦ 4 . . . . . ¦ . 3 . ¦ . . . 2 . . ¦ . 6 . ¦ . . 8 ------+-------+------- 2 . . ¦ . 7 3 ¦ . . . . . . ¦ . . . ¦ . . . . . 7 ¦ 6 . . ¦ 1 . . ------+-------+------- . . . ¦ . 6 . ¦ . . 1 4 5 . ¦ . 2 8 ¦ . . 6 . . . ¦ . . . ¦ 9 . . ------+-------+------- . . 3 ¦ . . . ¦ 8 . . . . . ¦ . 9 . ¦ . . . 9 . . ¦ . 5 . ¦ . . 7 ------+-------+------- 4 . . ¦ . 5 . ¦ . . 3 . . . ¦ . 4 . ¦ . . . . . 8 ¦ 2 . 7 ¦ 9 . . ------+-------+------- . . 6 ¦ . . . ¦ 4 . . 2 1 . ¦ . . . ¦ . 8 9 . . 5 ¦ . . . ¦ 7 . . ------+-------+------- . . 1 ¦ 7 . 9 ¦ 8 . . . . . ¦ . 6 . ¦ . . . 5 . . ¦ . 8 . ¦ . . 6 ------+-------+------- 3 . . ¦ . 5 . ¦ . . 1 . . . ¦ . 6 . ¦ . . . . . 8 ¦ . . . ¦ 5 . . ------+-------+------- . . 6 ¦ . . . ¦ . . . 4 . . ¦ 1 8 . ¦ . 9 7 2 . . ¦ . 7 . ¦ . . . ------+-------+------- . . 1 ¦ . . 2 ¦ 4 . . . . . ¦ . . . ¦ . . . . . . ¦ 4 9 . ¦ . . 8 ------+-------+------- 8 . . ¦ . 3 . ¦ . . 6 . . . ¦ . 5 . ¦ . . . . . 6 ¦ . . . ¦ 5 . . ------+-------+------- . . . ¦ . . . ¦ 7 . . 6 5 . ¦ . 8 9 ¦ . . 1 . . . ¦ . 6 . ¦ . . 3 ------+-------+------- . . 2 ¦ 3 . . ¦ 8 . . . . . ¦ . . . ¦ . . . 1 . . ¦ . 2 5 ¦ . . . ------+-------+------- The text represents each 9X9 grid in this order: Top left, Top Right, Middle, Bottom Left, Bottom Right. Kranser. Back to top Ruud Site Admin Joined: 17 Sep 2005 Posts: 708 : Location: Netherlands Items Posted: Mon Oct 24, 2005 12:27 am    Post subject: It is solvable. Basic solving of Top-left places a 3 in r9c7. That seems to be enough for my solver to crack the Middle grid. It used multicoloring, template exclusions and uniqueness test, amongst the more common solving methods. I haven't tried all 5, just needed those 2. Just tell me if you want me to post the answer. Back to top kranser Joined: 18 Aug 2005 Posts: 35 : Items Posted: Mon Oct 24, 2005 8:14 am    Post subject: Thanks for the reply and the hint. My solver doesn't do multicolouring or uniqueness test yet, so that might explain why it couldn't solve it. I think TheTimes must have missed a digit somewhere, as a 45min (very basic) samurai should not need multicolouring - should it?! In fact, do any newspaper published puzzles require multicolouring? Kranser. Back to top Ruud Site Admin Joined: 17 Sep 2005 Posts: 708 : Location: Netherlands Items Posted: Mon Oct 24, 2005 11:46 am    Post subject: kranser wrote: I think TheTimes must have missed a digit somewhere, as a 45min (very basic) samurai should not need multicolouring - should it?! Maybe it doesn't. I looked at only 2 of the 5 grids. Back to top petef Joined: 14 May 2005 Posts: 8 : Location: West Sussex Items Posted: Tue Oct 25, 2005 7:21 pm    Post subject: The problem with this puzzle is that there are many solutions. There are four ways of completing the central Sudoku, two answers for ABCD but I estimate that there are 10s or 100s of thousands of solutions for the whole grid. There is some discussion of this on the Su Doku / Times forum. I've had no reply from The Times yet. Back to top Ruud Site Admin Joined: 17 Sep 2005 Posts: 708 : Location: Netherlands Items Posted: Tue Oct 25, 2005 10:40 pm    Post subject: OK, I've given it the full treatment. The uniqueness test is worthless on a sudoku with multiple solutions, so I disabled it. This is the maximum you can get out of the middle grid. Code: 4 6 .|9 5 8|1 . 3 1 9 .|. 4 .|5 . 8 3 5 8|2 1 7|9 6 4 -----+-----+----- 7 3 6|8 9 1|4 5 2 2 1 4|. 7 .|6 8 9 9 8 5|. 2 .|7 3 1 -----+-----+----- 6 2 1|7 3 9|8 4 5 8 4 .|. 6 .|. . 7 5 7 .|. 8 .|. . 6 r3c1, r3c2, r8c1 and r8c2 all have (2,7) as candidate, but Top-left grid and Top-right grid have multiple solutions on the shared (2,7) candidates, so no help there. The remaining cells can be filled in 2 patterns, also here the connections to Bottom-left and Bottom-right have multiple solutions. I suggest you send in 2 solutions: A=8, B=1, C=4, D=6 A=8, B=1, C=6, D=4 Though the whole Samurai has many solutions, these are the only 2 possible answers for ABCD. Ruud. Back to top Lardarse Joined: 06 Sep 2005 Posts: 11 : Location: Bristol, UK Items Posted: Wed Oct 26, 2005 7:25 am    Post subject: Too late, Ruud - the competition closed on Sunday Back to top petef Joined: 14 May 2005 Posts: 8 : Location: West Sussex Items Posted: Wed Oct 26, 2005 7:33 am    Post subject: No, I think that the closing date for that pair of puzzles is 2nd November. However it has been reported that the email address for entries bounces. Back to top kranser Joined: 18 Aug 2005 Posts: 35 : Items Posted: Wed Oct 26, 2005 7:55 am    Post subject: petef wrote: No, I think that the closing date for that pair of puzzles is 2nd November. However it has been reported that the email address for entries bounces. Yes, I had it bounce on Sunday, but yesterday it seemed to work! So maybe it was fixed. Kranser. Back to top kranser Joined: 18 Aug 2005 Posts: 35 : Items Posted: Wed Oct 26, 2005 7:57 am    Post subject: petef wrote: The problem with this puzzle is that there are many solutions. There are four ways of completing the central Sudoku, two answers for ABCD but I estimate that there are 10s or 100s of thousands of solutions for the whole grid. There is some discussion of this on the Su Doku / Times forum. I've had no reply from The Times yet. The only good thing about the puzzle is that my solver finds an X-Wing, Swordfish AND Jellyfish while trying to solve it - but gets to about the same place as Ruud's post. Does anyone else spot the Jellyfish? Kranser. Back to top petef Joined: 14 May 2005 Posts: 8 : Location: West Sussex Items Posted: Thu Oct 27, 2005 9:18 pm    Post subject: petef wrote: I think that the closing date for that pair of puzzles is 2nd November. I've just got back my copy of the copy of the paper. Entries must actually be received by Tuesday 1st November. I've still had no response from The Times about the multiple solutions. Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         Sudoku Programmers Forum Index -> Exotic sudoku All times are GMT Page 1 of 1   Jump to: Select a forum Sudoku----------------Solving sudokuSetting sudokuProgramming sudokuThe mathematics of sudokuExotic sudoku Library----------------PuzzlesSoftwareSudoku elsewhere Not sudoku----------------Random thoughtsForum feedback  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum   Powered by phpBB © 2001, 2005 phpBB Group Igloo Theme Version 1.0 :: Created By: Andrew Charron