visit-all-nodes.clj

;;visit all nodes using reduce
;;clojure
;;store nodes in visited order.

(defn visit [g]
  (let [walk (fn walk [g seen n]
               (reduce (fn [seen, m]
                           (cond
                            (seen m) seen
                            :else (walk g (conj seen m) m) )) seen (g n))
               )]
    (walk g (sorted-set :u1) :u1)))

;;example
(visit {:u1 [:u2 :u3], :u2 [:u4], :u3 [:u4 :u6], :u4 [:u5], :u6 [:u5 :u7]})

;;#{:u1 :u2 :u3 :u4 :u5 :u6 :u7}