language ESSENCE 1.2.0
$ prob133.essence: Knapsack Problem
$
$ 03 September 2007
$

given U new type enum,
      s, v : function (*total*) U -> int (*1..*),
      B, K : int (*1..*)

find U' : set of U

such that
    sum u in U' . s(u) <= B,
    sum u in U' . v(u) >= K