Comments on: Wrap-around Consecutive Samurai Star http://www.garethmoore.co.uk/2009/07/wrap-around-consecutive-samurai-star/ Puzzle and brain-training author Sun, 10 Mar 2013 11:39:58 +0000 http://wordpress.org/?v=2.8.4 hourly 1 By: Christine http://www.garethmoore.co.uk/2009/07/wrap-around-consecutive-samurai-star/comment-page-1/#comment-245 Christine Wed, 08 Jul 2009 19:29:28 +0000 http://www.garethmoore.co.uk/?p=488#comment-245 This was a great puzzle - just the right degree of difficulty for me - challenging but manageable. As you probably know by now, I don't do the sudoku solving jargon (I've never got to grips with it, though I'm sure I use some of the strategies without realising it). Just to say that once started I managed this without too much difficulty. Like Spittledung I started with the lower centre box, and then looked at the very long line of consecutive numbers in the middle, and with some thought the puzzle seemed to fall into place. It took me about an hour to complete. Now to get back to the 12 x 12 one - I'm not getting anywhere fast with that. I may be asking for a few hints soon! This was a great puzzle – just the right degree of difficulty for me – challenging but manageable. As you probably know by now, I don’t do the sudoku solving jargon (I’ve never got to grips with it, though I’m sure I use some of the strategies without realising it). Just to say that once started I managed this without too much difficulty. Like Spittledung I started with the lower centre box, and then looked at the very long line of consecutive numbers in the middle, and with some thought the puzzle seemed to fall into place. It took me about an hour to complete.

Now to get back to the 12 x 12 one – I’m not getting anywhere fast with that. I may be asking for a few hints soon!

]]> By: Gareth Moore http://www.garethmoore.co.uk/2009/07/wrap-around-consecutive-samurai-star/comment-page-1/#comment-243 Gareth Moore Wed, 08 Jul 2009 17:07:01 +0000 http://www.garethmoore.co.uk/?p=488#comment-243 Ah, now that's a good point - I'd overlooked that! I ran my sudoku analysis software on it but it doesn't look at multiple groupings of consecutive markers in the same region, considering only any chosen pair at once. If you <em>don't</em> look at region cooccurrences then you need a hidden quad towards the end, but of course any human solver would make the more intuitive deduction instead. :) <p> You can see a similar issue in Futoshiki if a computer solver considers only pairs (the obvious way to implement). If a>b<c in a single row/column then in (say) a 5x5 grid clearly b cannot be 4, but if you consider only pairs then the only deduction the computer will make is that b is not 5 (without any other information at any rate). Whilst it's not hard to make a machine more intelligent (it can easily run an exhaustive search) the problem soon becomes that you make puzzles that are far too hard - so I've always thought it better to err on the side of too easy than too hard! :) Of course, if you have the time and inclination then the best solution of all is to make explicit implementations of all the things you find yourself doing as a human solver - then you can be sure it's fair <em>and</em> tricky! :) Ah, now that’s a good point – I’d overlooked that! I ran my sudoku analysis software on it but it doesn’t look at multiple groupings of consecutive markers in the same region, considering only any chosen pair at once. If you don’t look at region cooccurrences then you need a hidden quad towards the end, but of course any human solver would make the more intuitive deduction instead. :)

You can see a similar issue in Futoshiki if a computer solver considers only pairs (the obvious way to implement). If a>b<c in a single row/column then in (say) a 5×5 grid clearly b cannot be 4, but if you consider only pairs then the only deduction the computer will make is that b is not 5 (without any other information at any rate). Whilst it’s not hard to make a machine more intelligent (it can easily run an exhaustive search) the problem soon becomes that you make puzzles that are far too hard – so I’ve always thought it better to err on the side of too easy than too hard! :) Of course, if you have the time and inclination then the best solution of all is to make explicit implementations of all the things you find yourself doing as a human solver – then you can be sure it’s fair and tricky! :)

]]> By: Spittledung http://www.garethmoore.co.uk/2009/07/wrap-around-consecutive-samurai-star/comment-page-1/#comment-240 Spittledung Tue, 07 Jul 2009 16:02:44 +0000 http://www.garethmoore.co.uk/?p=488#comment-240 Yum Yum Fun! :D ***** SPOILER! ***** I am not sure what nasty hidden set you were referring to. At the start of the puzzle I worked on the center box and very lower box. Then I did the conga line of consecutives in the middle right row. Once you do this and apply the samurai flower rule diligently, the puzzle breaks down rather nicely. I think there were a few times I had triplets with a pair of consecutive numbers with no bars in the row/column ... which meant the non-consecutive number had to be in the middle square. I enjoyed this one. Thanks. Yum Yum Fun! :D

*****
SPOILER!
*****

I am not sure what nasty hidden set you were referring to. At the start of the puzzle I worked on the center box and very lower box. Then I did the conga line of consecutives in the middle right row.

Once you do this and apply the samurai flower rule diligently, the puzzle breaks down rather nicely. I think there were a few times I had triplets with a pair of consecutive numbers with no bars in the row/column … which meant the non-consecutive number had to be in the middle square.

I enjoyed this one. Thanks.

]]>