////////////////////////////////////////////////////////////////////////
// File routes-stations.java

/*
            +-------------------------------------------------------+
            |                      +-------------+                  |
            v                      |             v                  |
 +----------------------------+    | +-------------------------+    |
 | Route                      |    | | Station                 |    |
 +----------------------------+    | +-------------------------+    |
 | String  name               |    | | String name             |    |
 | ALoS    stations           |-+  | | ALoR   routes           |-+  |
 +----------------------------+ |  | +-------------------------+ |  |
 | ALoS addStation(Station s) | |  | |  ALoS addRoute(Route r) | |  |
 +----------------------------+ |  | +-------------------------+ |  |
          +---------------------+  |       +---------------------+  |
          |                        |       |                        |
          |       +-------------+  |       |      +--------------+  |
          v       v             |  |       v      v              |  |
 +------------------------+     |  | +-------------------------+ |  |
 | ALoS                   |     |  | | ALoR                    | |  |
 +------------------------+     |  | +-------------------------+ |  |
            / \                 |  |            / \              |  |
            ---                 |  |            ---              |  |
             |                  |  |             |               |  |
      +------+------+           |  |      +------+---------+     |  |
      |             |           |  |      |                |     |  |
      v             v           |  |      v                v     |  |
+-------+   +-------------+     |  |  +-------+  +-----------+   |  |
| MTLoS |   | ConsLoS     |     |  |  | MTLoR |  | ConsLoR   |   |  |          
+-------+   +-------------+     |  |  +-------+  +-----------+   |  |       
            | Station fst |-----+--+             | Route fst |---+--+      
            | ALoS    rst |-----+                | ALoR  rst |---+
            +-------------+                      +-----------+
*/

class Route{
  String name;
  ALoS stations;

  Route(String name){
    this.name = name;
    this.stations = new MTLoS();
  }

  // add a tation to the route, when initializing
  void addStation(Station s){
    this.stations = new ConsLoS(s, this.stations);
    s.addRoute(this);
  }
}

abstract class ALoR { }

class MTLoR extends ALoR{
    MTLoR(){ }
}

class ConsLoR extends ALoR{
    Route fst;
    ALoR  rst;

    ConsLoR(Route fst, ALoR rst) {
	this.fst = fst;
	this.rst = rst;
    }
}

class Station {
    String name;
    ALoR routes;

    Station(String name){
	this.name = name;
	this.routes = new MTLoR();
    }

  // add a route to a station, when initializing
    void addRoute(Route r){
        this.routes = new ConsLoR(r, this.routes);
    }
}


abstract class ALoS { }

class MTLoS extends ALoS{
    MTLoS(){ }
}

class ConsLoS extends ALoS{
    Station fst;
    ALoS  rst;

    ConsLoS(Station fst, ALoS rst) {
	this.fst = fst;
	this.rst = rst;
    }
}

// "Examples of stations"

// Station ken = new Station("Kenmore");

// Station prk = new Station("Park");

// Station ctr = new Station("Center");

// Station nor = new Station("North");

// Station sci = new Station("Science");

// Station ash = new Station("Ashmont");

// Station dwn = new Station("Downtown");

// Station chs = new Station("Charles");


// "Make examples for the stations on the Blue Line:
// Bowdoin, State, and Wonderland"


// "Examples of routes"

// Route green = new Route("Green");

// Route red = new Route("Red");


// "Add stations to the green line"

// green.addStation(ken);

// green.addStation(prk);

// green.addStation(ctr);

// green.addStation(nor);

// green.addStation(sci);

// green.addStation(ken);


// "Add stations to the red line"

// red.addStation(ash);

// red.addStation(dwn);

// red.addStation(prk);

// red.addStation(chs);