for(String key:idMap.keySet()){
for(String subkey:idMap.get(key).keySet()){
ArcModel arc = arcMap.get(subkey);
if(arc == null) continue;
g.addEdge(idToVertex.get(arc.getSourceId()), idToVertex.get(arc.getTargetId()));
}
}
rpst = new RPST<DirectedEdge,Vertex>(g);