private void calcHeuristic(TrieNode node) {
		if (node.isLeaf()) {
			node.setHeuristic(node.getDepth());
		} else {
			for (TrieNode child : node.getChildren().values()) {
				calcHeuristic(child);
			}
			node.setHeuristic(getMaxChildHeuristic(node));
		}
	}