gistfile1.clj

(use 'clojure.contrib.seq-utils)

(def graph {:a [:b], :b [:a :c], :c [:b :d], :d [:c]})

(defn find-path
  "Find a path between a start and an end node."
  ([g start end]
     (if (contains? g start)
       (find-path g start end [])))
  ([g start end path]
     (let [p (conj path start)]
       (if (= start end)
         p
         (continue-path g (g start) end p)))))

(defn continue-path [g [n & ns] end path]
  (if n
    (or (and (not (includes? path n))
             (find-path g n end path))
        (recur g ns end path))))