Euler: Problem 92

pe_92.clj

;; Problem 92
;; "Elapsed time: 160349.067511 msecs"


(defn num-to-list [n]
  (if (zero? n)
    []
    (conj (num-to-list (quot n 10)) (rem n 10))))

(defn get-digits [n]
  (sort (filter #(not= 0 %) (num-to-list n))))
 
(defn add-square [s]
  (reduce + (map #(* % %) s)))
 
(defn-memo end-with-89? [digit-list]
    (cond (= digit-list [8 9]) true
          (= digit-list [1]) false
          :t (end-with-89? (get-digits (add-square digit-list)))))
 
(count  (filter true? (map end-with-89? (map get-digits (range 1 10000000)))))


;;user> (time (count (map get-digits (range 1 10000000))))
;;"Elapsed time: 118325.744157 msecs"