merge.clj

(defn acc-tail-merge
  "Trololo"
  [acc list1 list2 func]
  (cond
   (empty? list1) (concat acc list2)
   (empty? list2) (concat acc list1)
   :else (let [[first1 & rest1] list1
               [first2 & rest2] list2
               [small-first small-rest large-list] (if (func first1 first2) [first1 rest1 list2] [first2 rest2 list1])
               new-acc (concat acc [small-first])]
           (recur new-acc small-rest large-list func))))

(defn tail-merge
  "Lololo"
  [list1 list2 func]
  (acc-tail-merge [] (seq list1) (seq list2) func))