find-pin.clj

(ns find-pin)

(defn ^String to-pin 
  [^Integer x]
  (let [v (str x)]
   (.concat (apply str (repeat (- 4 (count v)) 0)) v)))

(defn ^java.lang.Boolean valid-pin? 
  [^String v]
    (and 
      (= 3 (count (distinct v)))
      (some true? 
            (->> (range 10) (map str) (map #(.concat % %)) (map #(.contains v %))))))

(prn (count (filter valid-pin? (map to-pin (range 10000)))))