orthonormal comments on A puzzle - Less Wrong

-6 Post author: Thomas 14 April 2012 06:55AM

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Comment author: orthonormal 14 April 2012 01:48:38PM 2 points [-]

Unless there's some clever structure to the optimal position, this is a problem best solved by computer search. Potentially it could make a good Project Euler problem, potentially not (depending on how much computation the best human-writable program requires to do it).

Also, this post gave the false impression that there was a known answer. That irritated me when I read the comments.

Comment author: gRR 14 April 2012 02:06:02PM 1 point [-]

I think I can prove 53 is the maximum. And the solution does have a nice structure.

Comment author: Thomas 14 April 2012 03:28:52PM *  -1 points [-]

Prove it, since your answer is correct, as far as I know.

Can you answer for the case of the two sets of pieces? Black and white, 32 of them. Again the color does not matter.

Comment author: gRR 14 April 2012 05:10:46PM 1 point [-]

No, I'll leave it to you for now.

For two sets, the answer is 118.

Comment author: Thomas 14 April 2012 05:14:30PM 1 point [-]

119.

Comment author: gRR 14 April 2012 05:43:35PM 1 point [-]

According to my proof, more than 128-10 is impossible. Are you sure?

Comment author: Thomas 14 April 2012 06:01:56PM *  4 points [-]

Comment author: gRR 14 April 2012 07:02:58PM 0 points [-]

Thanks! Clever trick with a rook and two bishops to reduce the length of the top boundary, I missed it.

Cebbs fxrgpu sbe n fvatyr frg: svefg, pbafvqre gjb xavtugf naq n xvat. Rnfl gb frr gurl unir ng yrnfg 4 serr pbaarpgvbaf, ab znggre ubj bgure cvrprf ner cynprq. Gura pbafvqre gur gbc obhaqnel (=cvrprf jvgu ng yrnfg bar serr hcjneq ovfubc-zbir naq ng yrnfg bar serr ebbx-zbir). Gur gbc obhaqnel pna'g or yrff guna 6 cvrprf, rnpu jvgu ng yrnfg bar serr pbaarpgvba, naq ng yrnfg bar bs gur obhaqnel cvrprf unf abguvat va gur ebjf nobir vg, fb vg unf ng yrnfg gjb serr pbaarpgvbaf. Nygbtrgure 64-(4+6+1)=53.

Comment author: TrE 14 April 2012 08:55:09PM 0 points [-]

Can you give a position for 53 'bounds'?

Comment author: gRR 14 April 2012 09:12:49PM 1 point [-]
Comment author: Thomas 14 April 2012 09:16:30PM 0 points [-]

What about the three sets? And four?

Comment author: gRR 14 April 2012 10:56:18PM 0 points [-]

Cool! Using the bishops trick, any N-sets for N>2 reduce to N*64 - 8