hierarchy.java

 TreeMap<Integer, List<Node>> nodesSortedByLevel = sc.roomGraph.getNodesSortedByLevel();
        Iterator<Map.Entry<Integer, List<Node>>> nodesSortedByLevelIterator  = nodesSortedByLevel.entrySet().iterator();
        while(nodesSortedByLevelIterator.hasNext()) {
            Map.Entry<Integer, List<Node>> e = nodesSortedByLevelIterator.next();
            for(Node n : e.getValue()) {
                if(n.getParent() == null && e.getKey() != 0) {
                    for(Edge edge : n.getNeighbors()) {
                        if(nodesSortedByLevel.get(e.getKey()-1).contains(edge.getNeighbor(n)))
                            n.setParent(edge.getNeighbor(n));
                    }
                }
                for(Edge edge : n.getNeighbors()) {
                    if(edge.getNeighbor(n).getLevel() == n.getLevel()+1)
                        n.getChildren().add(edge.getNeighbor(n));
                }
            }
        }