104.clj

(ns e104 
  (:require [clojure.contrib.math :as math
             clojure.contrib.string :as string
             ]))

(defn next-fib [[pos last value]]
  [(inc pos) value (+ last value)])

(def fibs (iterate next-fib [2 1 1]))

(defn pandigital?
  [numstring]
  (and (= 9 (count numstring))
       (= 9 (count (distinct (remove #(= \0 %) numstring))))))

(defn first-nine [somenum]
  (take 9 (str somenum)))

(defn last-nine [somenum]
  (take 9 (reverse (str somenum))))

(defn test-last [[pos last value]]
  (pandigital? (last-nine value)))

(defn test-first [[pos last value]]
  (pandigital? (first-nine value)))

(time (println (ffirst (take 1 (filter test-first fibs)))))
(time (println (ffirst (take 1 (filter test-last fibs)))))

(time (println (ffirst (take 1 (filter #(and (test-first %)
                                             (test-last %)) fibs)))))