// ExcludedRooms: composition program enforcing that course j is not
// assigned a room from its excluded set R[j].  Composed onto
// LLP-IntervalPartition via predicate conjunction:
//   [ LLP-IntervalPartition(s, f, G) && ExcludedRooms(R, G) ].

class ExcludedRooms {
  int[] ExcludedRooms(set<int>[] R, set<int>[] pre, int[] G) {
    int n = G.length;
    forbidden (j) : G[j] in R[j] =>
      advance : {
        G[j] = min r in [1..n] :
          !(r in R[j]) &&
          forall k in pre[j] : G[k] != r;
      };
    return G;
  }
}