This is what I ended up with, which I think is relatively clear and straightforward (but then, I'm not entirely unbiased :)
The algorithm is very close to what you described. - Generate all sub-sequences of length > 1 - Filter to keep only increasing subsequences - Tack on the empty sequence, which is what needs to be returned if there are no increasing sub-sequences - Sort by length in descending order - Take the first (longest) (fn [coll] (let [increasing? (fn [xs] (apply < xs)) n (count coll) sub-seqs (mapcat #(partition % 1 coll) (range 2 (inc n)))] (->> sub-seqs (filter increasing?) (cons []) (sort-by count >) first))) On Tuesday, June 12, 2012 12:11:07 PM UTC-7, Andy C wrote: > > Hi, > > First a quick disclaimer. Those are my first steps in Clojure so I am > not be super accustomed to the language entire landscape and might > miss some basics here. However I was able to solve my first 4clojure > hard problem https://www.4clojure.com/problem/53 and have some second > thoughts after looking up top contributor's solutions as well as mine. > Why it has to be so complicated??? > > Conceptually, you just reduce the list to list of lists using a simple > condition < . Then you filter items longer then 1. And at the same > time you reduce the output to a first longest list. In this case, > stack for recursion is really not required, although I did use it in > my solution since I could figure out the "reduction" based way to > partition the source sequence. > > It also seems that imperative solution would be quite straightforward > although maintaining at least 4 state variables is not compelling at > all. Bottom line, I want to have a idiomatic Clojure solution ... Any > insight .... > > Thx, > Andy > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en