Day 9: 441

d9golf.hs

@@ -0,0 +1,9 @@
+import Data.List
+m!(a,b)|a>=0,b>=0,a<length m,c<-m!!a,b<length c=c!!b|let=9
+z m=(=<<)(m%)$(,)<$>[0..length m]<*>[0..length(m!!0)]
+m%p=[(p,m!p)|all((m!p<).(m!))$f p]
+f(x,y)=zip[x+1,x,x,x-1][y,y+1,y-1,y]
+x m g p|p`elem`g=[]|let=p:filter((/=9).(m!))(f p)
+m#g|v<-nub$(=<<)(\v->x m(g\\[v])v)g=last$m#v:[g|v==g]
+b i=product.take 3.reverse.sort.map(length.(i#).pure.fst)$z i
+main=interact$show.((,).b<*>sum.map((+1).snd).z).map(map$read.pure).lines