tree-height.clj

(ns try)

;; find the height of a tree
;; try> (height nil)
;; 0
;; try> (height {:L {:R {:L {:L nil} :R nil}}})
;; 4

(defn height-simple [t]
  (if (nil? t)
    0
    (-> (max (-> t :L height-simple)
             (-> t :R height-simple))
        inc)))

(defn height [t]
  (if (nil? t)
    0
    (-> (reduce max (map height (-> t
                                    (select-keys [:L :R])
                                    vals)))
        inc)))

(defn height-destruct [{:keys [L R] :as t}]
  (if (nil? t)
    0
    (-> (max (height-destruct L)
             (height-destruct R))
        inc)))

(defn height-red [{:keys [L R] :as t}]
  (if (nil? t)
    0
    (->> (map height-red [L R])
         (reduce max)
         inc)))