order.clj

;; http://xkcd.com/287/

(defn order [menu amount items]
  (cond
    (< amount 0) []
    (= amount 0) [items]
    :else (reduce
            (fn [meals, [item price]]
              (concat meals (order menu (- amount price) (into [item] items)))) [] menu)))

(def menu {:mixed_fruit 215, :french_fries 275, :side_salad 335, :hot_wings 355, :mozzarella_sticks 420, :sampler_plate 580})

(distinct (map #(sort-by str %) (order menu 1505 [])))