private void addChildrenToHeuristicMap(Map <Integer, Integer> heuristicMap) {
	   for (TrieNode child : this.children.values()) {
		   Integer weight = heuristicMap.get(Integer.valueOf(child.getId()));
		   if (weight == null) {
			   try {
				   heuristicMap.put(Integer.valueOf(child.getId()), Integer.valueOf(child.getHeuristic()));
			   } catch (Exception e) {
				   e.printStackTrace();
			   }
		   }
	   }
   }