Hi, I just started to learn clojure in a more serious way and I am
doing the first level of the greplin challenge.
I made it to work with a short palindrome like the example they give
me, but when it comes to work with the input file, it takes for ever
and I have to stop it.
$ time clj level1.clj
^C
real 11m35.477s
user 1m44.431s
sys 9m3.878s
This is my code:
(defn palindrome? [s]
(= s (reduce str (reverse s))))
(defn all-combs [in]
(let [len (count in)]
(for [i (range 0 (- len 2)), j (range (+ i 1) len)]
(subs in i j))))
(defn max-comp [x y]
(let [lenx (count x), leny (count y)]
(cond (< lenx leny) 1
(= lenx leny) 0
(> lenx leny) -1)))
;;(let [input "I like racecars that go fast"]
(let [input (slurp "../_input/level1.in")]
(println (nth (sort max-comp (filter palindrome? (all-combs
input))) 0)))
The input file is this http://challenge.greplin.com/static/gettysburg.txt
It looks a bit procedural. It is long, but I don't think is the
biggest bottleneck, I think it is my approach to create all the
combinations possible for substrings. Maybe I should be using a lazy
seq? How would I go to do that?
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