4clojure

problem_112.clj

(defn find-coll [max-sum acoll]
  (if (empty? acoll)
    [() max-sum]
    (loop [max-sum max-sum
           cur ()
           coll acoll]
      (cond (< max-sum 0) [(list* cur) -1]
            (nil? (seq coll)) [(list* cur) max-sum]
            (and (number? (first coll)) (> (first coll) max-sum)) [(concat () cur) -1]
            (number? (first coll)) (recur (- max-sum (first coll))
                                          (concat cur (list (first coll)))
                                          (rest coll))
            :else (let [[cur-coll remaining] (find-coll max-sum
                                                        (first coll))]
                    (cond (>= remaining 0) (recur remaining
                                                  (concat cur (list cur-coll))
                                                  (rest coll))
                          (empty? cur-coll) [cur -1]
                          :else [(concat cur (list cur-coll)) remaining]))))))

(defn find-tree [max-sum coll]
  (first (find-coll max-sum coll)))