public void showAllNodeAndEdge(){
		System.out.println("!!!!! dijkstra node and edge !!!!!" );
		for( Node node : nodes ){
			System.out.print("node:" + node.nodeID);
			for( Edge edge : node.edges){
				System.out.print(" edge:" + edge.to + "(" + edge.cost + ")");
			}
			System.out.println("");
		}
	}