Clojure subsets

subsets.clj

(use 'clojure.contrib.combinatorics)

(def small-numbers [ 1 2 3 4 6 ])
(def large-numbers [ 3 4 9 14 15 19 28 37 47 50 54 56 59 61 70 73 78 81 92 95 97 99 ])

(defn largest-sum-of-rest?
  [ col ]
  (let [ [ largest & others ] (reverse (sort col)) ]
    (= largest (reduce + others))))

(defn size
  [ col ]
  (reduce (fn [x _] (inc x)) 0 col))

(defn num-subsets-with-largest-sum-of-rest
  [ col ]
  (size (filter largest-sum-of-rest? (clojure.contrib.combinatorics/subsets col))))

(println (num-subsets-with-largest-sum-of-rest large-numbers))