class City {
   private String name;
   
   
   public City(String name){
      this.name = name;
   }
   
   public getName(){
      return this.name;
   }

}

class Link {
   private City cityA;
   private City cityB;
   private int weight;
   private boolean isRail;
   
   public Link(City a, City b, int weight, boolean isRail){
   
   }
   
   public City getCityA(){
   
   }
   
   public City getCityB(){
   
   }
   
   public boolean isCityInLink(City city){
      boolean foundCity = false;
      if((cityA == city) || (cityB == city)){
         foundCity = true;
      }
      return foundCity;
   }
   
}


class TransportNet{
   private List<Link> links = new ArrayList<Link>();
   private List<City> cities = new ArrayList<City>();
   
   public TransportNet(){
      //add cities
      cities.add(new City("Sydney"));
      cities.add(new City("Melbourne"));
      cities.add(new City("London"));
      cities.add(new City("Venice"));
      
      //add links
      addLink("Sydney", "Melbourne", 10, false);
      addLink("Sydney", "Melbourne", 12, true);
      addLink("Sydney", "Venice", 45345, false);
      
   }
   
   private addLink(String city1, String city2, int weight, boolean isRail){
      City a = getCitybyName(city1);
      City b = getCitybyName(city1);
      
      links.add(new Link(a, b, weight, isRail);
   }
   
   public getCitybyName(String name){
   
   }
   
   public List<City> getCities(){
      return cities;
   }
   
   public getLinks(City cityA){
      List<Link> cityLinks = new ArrayList<Link>();
      for(Link link : links){
         if(link.isCityInLink(cityA)){
            cityLinks.add(link);
         }
      }
   }
   
}