Re: "Divide" challenge

Brute force algorithm (C++) had problems even with 8 machines

That surprises me. Unless I'm very much mistaken there are 8!/(4! * 2!) == 840 possibilities, which doesn't look like a terribly high number, and looks very brute-forceable to me. Is there a deeper reason why it should be so hard to brute force?

Comment on Re: "Divide" challenge

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Re^2: "Divide" challenge by grizzley (Chaplain) on Mar 11, 2009 at 17:55 UTC
Yes, it seems you are right. Maybe it was about dividing 16-machines into two 8-machines groups, which is 16!/(8!*2!) = 259.459.200 possibilities (correct me if I am wrong). This, too, doesn't look like apocalypse, but hey, there is still 64-machines group :) Anyway, at the meeting, the speaker was talking so loud I couldn't focus on the problem! :) Only AI::Genetic came to my mind, what I tried yesterday, but this package doesn't work well with 'find best permutation' problems. I found only some C implementations on the web, which must be adopted to perl. When I develop working example, I'll paste it in monastery.	[reply]

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Re^2: "Divide" challenge
by grizzley (Chaplain) on Mar 11, 2009 at 17:55 UTC

Yes, it seems you are right. Maybe it was about dividing 16-machines into two 8-machines groups, which is 16!/(8!*2!) = 259.459.200 possibilities (correct me if I am wrong). This, too, doesn't look like apocalypse, but hey, there is still 64-machines group :)

Anyway, at the meeting, the speaker was talking so loud I couldn't focus on the problem! :) Only AI::Genetic came to my mind, what I tried yesterday, but this package doesn't work well with 'find best permutation' problems. I found only some C implementations on the web, which must be adopted to perl. When I develop working example, I'll paste it in monastery.

[reply]