public string FindShortestRoutes(MetroMapObject map, string start, string end)
{
StationObject starting = GetStation(map, start);
StationObject ending = GetStation(map, end);
RouteObject routeFromOrigin = new RouteObject(starting, ending);
routeFromOrigin.AddStopToRoute(starting);
RouteBundle shortestRoutes = ExporeAllBranches(routeFromOrigin, new RouteBundle(), map);
return(shortestRoutes.PrintResult());
}
private RouteBundle ExporeAllBranches(RouteObject seedRoute, RouteBundle allRoutes, MetroMapObject mapE)
{
if (debug)
{
Console.WriteLine($"smallest path so far: {lowestPathSoFar}");
}
StationObject currentStation = seedRoute.CurrentStation();
//seedRoute.AddStopToRoute(currentStation);
if (debug)
{
Console.WriteLine($"length of route: {seedRoute.Distance}");
}
if (debug)
{
Console.WriteLine($"~~~~~current station~~~~~: {currentStation.Name}");
}
//the for loop below is to handle any station with more than 1 stop left to explore,
//either dumping it or finding a route
if (debug)
{
Console.WriteLine($"current station # of contacts: {currentStation.NumberOfContacts}");
}
for (int s = 0; s < currentStation.NumberOfContacts; s++)
{
if (debug)
{
Console.WriteLine($"location in for loop: <{s}>");
}
//Console.WriteLine($"destination name: {seedRoute.Destination.Name}");
StationObject addStation = GetStation(mapE, currentStation.ConnectionList[s]);
if (debug)
{
Console.WriteLine($"next station: [{addStation.Name}]");
}
if (addStation.Name == seedRoute.Destination.Name)
{
allRoutes.AddRoute(seedRoute);
if (seedRoute.Distance >= 3)
{
seedRoute.CheckLineSwitch(currentStation, addStation, seedRoute.PreviousStation());
}
if (debug)
{
Console.WriteLine($"# # # # NEW BRANCH ADDED # # # #");
}
if (seedRoute.Distance <= lowestPathSoFar)
{
lowestPathSoFar = seedRoute.Distance;
}
if (debug)
{
Console.WriteLine($"Is new record?: {seedRoute.Distance <= lowestPathSoFar}");
}
if (debug)
{
Console.WriteLine($"smallest path so far: {lowestPathSoFar}");
}
continue;
}
if (debug)
{
Console.WriteLine($"next station # of contacts: {addStation.NumberOfContacts}");
Console.WriteLine($"enters recursive loop: {seedRoute.Distance + 1 < lowestPathSoFar && addStation.NumberOfContacts > 1 && !seedRoute.AlreadyCheckedThisStation(addStation)}");
Console.WriteLine($"already checked the next station? {seedRoute.AlreadyCheckedThisStation(addStation)}");
}
if (seedRoute.Distance + 1 < lowestPathSoFar && addStation.NumberOfContacts > 1 && !seedRoute.AlreadyCheckedThisStation(addStation))
{
RouteObject clone = seedRoute.CloneRoute();
clone.AddStopToRoute(addStation);
if (clone.Distance >= 3)
{
clone.CheckLineSwitch(currentStation, addStation, seedRoute.PreviousStation());
}
allRoutes = ExporeAllBranches(clone, allRoutes, mapE);
}
if (debug)
{
Console.WriteLine($"/////current station post loop/////: {currentStation.Name}");
}
}
//below is the part of code that should only be accessed by branches with a single station remaining.
StationObject nextStation = GetStation(mapE, currentStation.ConnectionList[0]);
if (debug)
{
Console.WriteLine($"next station: {nextStation.Name}");
Console.WriteLine($"next station # of contacts: {nextStation.NumberOfContacts}");
}
string dest = seedRoute.Destination.Name;
if (seedRoute.Distance + 1 <= lowestPathSoFar && nextStation.Name == dest)
{
seedRoute.AddStopToRoute(nextStation);
if (seedRoute.Distance >= 3)
{
seedRoute.CheckLineSwitch(currentStation, nextStation, seedRoute.PreviousStation());
}
allRoutes.AddRoute(seedRoute);
lowestPathSoFar = seedRoute.Distance;
if (debug)
{
Console.WriteLine($"smallest path so far: {lowestPathSoFar}");
}
}
allRoutes.PruneLongRoutes();
return(allRoutes);
}