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Brainteaser thread http://www.rcbroughton.co.uk/sudoku/forum/viewtopic.php?f=17&t=32 |
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Author: | udosuk [ Tue May 20, 2008 8:58 am ] |
Post subject: | Re: Brainteaser thread |
Richard has gone to vacation already? Was asking if he could check whether the 21 shafts as {1,2,...,21} would produce any plausible solution... |
Author: | Glyn [ Tue May 20, 2008 9:44 am ] |
Post subject: | Re: Brainteaser thread |
Richard on vacation. Oh well that gives us all a chance to catch up , hope he's left a machine running to complete the task. Matt I take it that a complete sequence of shafts from 1 through to 21 was not the solution you had then. |
Author: | rcbroughton [ Tue May 20, 2008 5:32 pm ] |
Post subject: | Re: Brainteaser thread |
Hope to see a solution waiting for me on my pc when I get back on 30th. Only have mobile phone browser until then. Plenty of time for someone else to find a solution. Hasta luego ! My paella and cerveza is waiting for me |
Author: | rcbroughton [ Fri May 30, 2008 4:57 pm ] |
Post subject: | Re: Brainteaser thread |
Good News & Bad News I'm afraid. Good News, I'm back from vacation and will start to catch up on some of the posting that's been going on . . Bad News . . . Having left my Golden Rods calculator running for 10 days and it having now tried over 261,752,700,000 possibilities, we still have no hits. I know the logic is sound - it finds even 4 rod solutions in seconds - so must be a very well hidden solution - maybe it is unique! If anyone wants to put some CPU power into the solution, I could distribute the solver and we could all start from different points (even this far into the possibilities, we are still only at a first rod of {1,2,4,11,29,4} and [Edit:] trying rod 2 combinations starting with 20. Rgds |
Author: | udosuk [ Sat May 31, 2008 4:01 am ] |
Post subject: | Re: Brainteaser thread |
I definitely know the existence of one solution, and remember the source has claimed it being unique (I've lost the link to the source however, and can't google it up anymore ). Richard, is it possible to ask your solver to separately run on another search using {1..21} as the lengths of the 21 shafts? I don't think it would take too long. Or if you don't mind upload your solver up for us to try ourselves. |
Author: | rcbroughton [ Sat May 31, 2008 8:12 am ] |
Post subject: | Re: Brainteaser thread |
udosuk wrote: I definitely know the existence of one solution, and remember the source has claimed it being unique (I've lost the link to the source however, and can't google it up anymore ). On a separate machine, I'm currently trying out limiting the shafts to 1..21, picking up on your hint. No hits yetRichard, is it possible to ask your solver to separately run on another search using {1..21} as the lengths of the 21 shafts? I don't think it would take too long. Or if you don't mind upload your solver up for us to try ourselves. [Edit] . . . and since we didn't see a 1..n solution for 4 or 5 rods, I'm not holding my breath for a 1..21 solution |
Author: | rcbroughton [ Sun Jun 01, 2008 12:30 pm ] |
Post subject: | Re: Brainteaser thread |
First solution has dropped out of the search: (and it doesn't use 1 ... 21) {1, 4, 25, 6, 14, 3} {8, 10, 16, 12, 9} {2, 22, 19, 13} {7, 33, 11} {15, 27} {39} Still looking for more . . . Rgds Richard |
Author: | udosuk [ Sun Jun 01, 2008 1:54 pm ] |
Post subject: | Re: Brainteaser thread |
Well done Richard! Bow to you! I suspect you'll find other solutions pretty soon. I'm still holding my breath for a solution with shafts {1..21}. Perhaps the original source was referring to that being unique. Or it has been proved utterly wrong with a brute force search like this and thus has disappeared from the googling range over these years. To confess, I don't have the solution with me all this time. (It was on a corrupted old hard drive which I still haven't found time to recover. But I definitely know a solution exists, which might or might not be the one Richard found first. From vague memory it doesn't look like it so I guess there are probably more. Luckily Richard has found at least one solution to bail me out, or I would have to spend a lot of time digging it from my corrupted drive or some old archives. ) Also with that Richard has become the official winner this time (well he is no matter what). So whenever you like you could post another brainteaser/riddle. Hopefully it won't be a cpu-teaser (or more exact a cpu-workout) like mine. |
Author: | Glyn [ Sun Jun 01, 2008 3:00 pm ] |
Post subject: | Re: Brainteaser thread |
Well done Richard. and thanks Matt for setting it. It has forced me into having a crack at programming again, so not an entirely fruitless exercise for me. As regards the {1..21} set this may be within the possible range of a manual calculation at least for the early placements. e.g 1 is either on the shortest rod or has 21 as its only neighbour. Edit. {1..21} is manually checkable and has no solution. Failure to place 7 removes the last option. |
Author: | rcbroughton [ Sun Jun 01, 2008 4:07 pm ] |
Post subject: | Re: Brainteaser thread |
Ok - a nice bit of gentle arithmetic then . . . Please fill in the missing digits in this sum, similar to the famous Feynman Long Division: Attachment: equation.png [ 4.2 KiB | Viewed 16745 times ] |
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