public void AddStation(string stationName)
{
if (!HasStation(stationName))
{
Station station = new Station(stationName);
_stations.Add(station);
}
}
public void AddConnection(string lineName, string station1Name, string station2Name)
{
if (!HasStation(station1Name)) { throw new ArgumentException("Invalid connection! Station " + station1Name + " does not exist."); }
if (!HasStation(station2Name)) { throw new ArgumentException("Invalid connection! Station " + station2Name + " does not exist."); }
Station station1 = new Station(station1Name);
Station station2 = new Station(station2Name);
// Direction 1
Connection connection1 = new Connection(lineName, station1, station2);
_connections.Add(connection1);
// Direction 2
Connection connection2 = new Connection(lineName, station2, station1);
_connections.Add(connection2);
}
private void AddToNetwork(Station station1, Station station2)
{
if (_network.ContainsKey(station1))
{
List<Station> connectingStations = _network[station1];
if (!connectingStations.Contains(station2))
{
connectingStations.Add(station2);
}
}
else
{
List<Station> connectingStations = new List<Station>() { station2 };
_network.Add(station1, connectingStations);
}
}
public bool HasConnection(string lineName, string station1Name, string station2Name)
{
Station station1 = new Station(station1Name);
Station station2 = new Station(station2Name);
foreach (Connection connection in _connections)
{
if (string.Compare(connection.LineName, lineName) == 0)
{
if ((connection.Station1.Equals(station1)) &&
(connection.Station2.Equals(station2)))
{
return true;
}
}
}
return false;
}
public Connection(string lineName, Station station1, Station station2)
{
LineName = lineName;
_station1 = station1;
_station2 = station2;
}
/// <summary>
/// This method is based on a well-known bit of code called Dijkstra's Algorithm, which figures out the shortest path between two nodes on a graph.
/// </summary>
/// <param name="startStationName"></param>
/// <param name="endStationName"></param>
/// <returns></returns>
public List<Connection> GetDirections(string startStationName,
string endStationName)
{
if (!HasStation(startStationName)) { throw new ArgumentException("Invalid connection! Station " + startStationName + " does not exist."); }
if (!HasStation(endStationName)) { throw new ArgumentException("Invalid connection! Station " + endStationName + " does not exist."); }
Station start = new Station(startStationName);
Station end = new Station(endStationName);
List<Connection> route = new List<Connection>();
List<Station> reachableStations = new List<Station>();
Dictionary<Station, Station> previousStations = new Dictionary<Station, Station>();
List<Station> neighbors = _network[start];
for (int i = 0; i < neighbors.Count; i++)
{
Station station = neighbors[i];
if (station == end)
{
route.Add(GetConnection(start, end));
return route;
}
else
{
reachableStations.Add(station);
previousStations.Add(station, start);
}
}
List<Station> nextStations = new List<Station>();
nextStations.AddRange(neighbors);
Station currentStation = start;
// searchLoop:
for (int j = 1; j < _stations.Count; j++)
{
List<Station> tmpNextStations = new List<Station>();
for (int k = 0; k < nextStations.Count; k++)
{
Station searchStation = nextStations[k];
reachableStations.Add(searchStation);
currentStation = searchStation;
List<Station> currentNeighbors = _network[currentStation];
for (int l = 0; l < currentNeighbors.Count; l++)
{
Station neighbor = currentNeighbors[l];
if (neighbor == end)
{
reachableStations.Add(neighbor);
previousStations.Add(neighbor, currentStation);
break;
}
else if(!reachableStations.Contains(neighbor))
{
reachableStations.Add(neighbor);
tmpNextStations.Add(neighbor);
previousStations.Add(neighbor, currentStation);
}
}
}
nextStations = tmpNextStations;
}
// We've found the path by now
bool keepLooping = true;
Station keyStation = end;
Station loopingStation;
while (keepLooping)
{
loopingStation = previousStations[keyStation];
route.Add(GetConnection(loopingStation, keyStation));
//route.Add(0, GetConnection(loopingStation, keyStation));
if (start == loopingStation)
{
keepLooping = false;
}
keyStation = loopingStation;
}
return route;
}
private Connection GetConnection(Station station1, Station station2)
{
foreach (Connection connection in _connections)
{
Station one = connection.Station1;
Station two = connection.Station2;
if ((station1.Name == one.Name) && (station2.Name == two.Name))
{
return connection;
}
}
return null;
}
