flengyel-4clojure-solution112.clj

;; flengyel's solution to Sequs Horribilis
;; https://4clojure.com/problem/112

(fn [n s]
  (letfn [(sequs [n s]
   (loop [acc 0 v [] s s]
     (if (or (empty? s) (< n acc))
       [acc v] 
       (let [elt (first s)]
   (if (vector? elt)
       (let [[m t] (sequs (- n acc) elt)
	           newacc (+ acc m)]
               (recur newacc  (if (empty? t) v (conj v t)) (rest s)))
            (let [newacc (+ acc elt)]
	      (recur newacc (if (< n newacc) v (conj v elt)) (rest s))))))))]
(second (sequs n s))))