gistfile1.clj

(defn possible-shrinks [s]
  (let [cnt (count s)]
    (concat
      (->> (iterate #(* % 2) 1)
        (take-while #(< % cnt))
        reverse
        (map #(drop % s)))
      (->> (iterate #(* % 2) 1)
        (take-while #(< % cnt))
        (map #(take % s)))
      (map
        (fn [n]
          (concat
            (take n s)
            (drop (inc n) s)))
        (range (count s))))))

(defn minimal-shrink [test s]
  (if-let [shrunk (loop [s (possible-shrinks s)]
                    (cond
                      (empty? s)
                      nil

                      (test (first s))
                      (first s)

                      :else
                      (recur (rest s))))]
    (recur test shrunk)
    s))