Am Montag 01 März 2010 21:40:16 schrieb Artyom Kazak:
Maybe we were compiling with different options? I compiled with -O2 -fvia-C -optc-O3. ... Oh, I know! I slightly changed the code.
import Data.Ord
e ((x, y), arr) p = [(t, arr // [(t, p)]) | t <- changes] where legit ps = [t | t <- allTurns ! ps, arr ! t == 0] changes = sortOn (length . legit) (legit (x, y)) sortOn = sortBy . comparing
Ah, that! I also tried that, that gets stuck for different values. With a little debugging output, I saw that it got stuck in a dead-end, always advancing a few steps and then backtracking. I'm now considering also the grand-children, that speeds things up and enters fewer dead-ends, but so far I haven't found a valuation which doesn't enter a dead-end for some values. I have an idea, though, also consider the distance from the border, try squares near the border first.
My version gives answer for 60, 60 in one second. But if both dimensions are >60, it won't finish. Yes, very strange.