dfs

(declare helper)

(defn- dfs [graph start end n acc]
  (if (= n end) (conj acc end)
    (let [ns (seq (disj (get graph n) (peek acc)))]
      (if (empty? ns)
        nil
        (helper graph start end ns (conj acc n))))))

(defn- helper [graph start end ns acc]
  (if (empty? ns)
    nil
    (let [p (dfs graph start end (first ns) acc)]
      (if p
        p
        (recur graph start end (rest ns) acc)))))

(defn findpath [graph start goal]
  (dfs graph start goal start []))