% Knapsack problem
% (c) 2007 Tomi Janhunen
%
% usage: lparse knapsack.lp | smodels 0

#option -cn=10
#option -cc=40

item(1..n).

weight c(I)=2*I.     % For example
weight v(I)=1000/I.  % For example

% Select which items are in

{ in(I) } :- item(I).

% Derive costs for the items

c(I) :- in(I), item(I).
broke :- c [ c(I):item(I) ].

% Enforce the limit

:- broke.

% Derive values for the items

v(I) :- in(I), item(I).
maximize [ v(I):item(I) ].

#hide item(I).
#hide v(I).
#hide c(I).