advent_or_day12.mzn

include "globals.mzn";
include "gecode.mzn";

%
% Data
%
int: N; % number of nodes
set of int: NODE = 1..N;

array[NODE, NODE] of int: distances;  % distance matrix
int: min_val = min([distances[i,j] | i,j in NODE where distances[i,j] > 0]);
int: max_val = max([distances[i,j] | i,j in NODE]);
array[NODE] of var min_val..max_val: d;

var min_val..sum(distances): distance;

constraint distance  = sum(d);

array[NODE] of var NODE: route;             % the circuit
constraint  forall(i in NODE) (
     distances[i, route[i]] = d[i]
   );
constraint circuit(route);
constraint value_precede(N, N-1, route);
   

%% Search
annotation relax_and_reconstruct(array[int] of var int,int);
annotation restart_luby(int);

solve
            :: relax_and_reconstruct(d ++
                        route, 93)
            :: restart_luby(100)
  minimize distance;


output [
       show(distance)
];