Re: [Haskell-cafe] Longest increasing subsequence

You can translate the following algorithm (written in Maple 11), which can be made purely functional. [For the cognoscenti: attributes are implemented in-place in Maple, but that is really just an instance of the Decorator pattern which can be just as easily implemented with a functional Map]. Note that all the assignments below are really just let bindings. Jacques longestIncreasingSequence := proc(L::list) local n,i,j,G; uses GraphTheory; n := nops(L); G := Digraph(n , {seq(seq(`if`(L[i] Arrivals(G,v)=[], Vertices(G)); [attributes(max(seq(len(v), v in sources)))]; end proc: