private static void TraceToSource(Bus FromBus, Bus BusThatStartedItAll, HashSet <Bus> busesInThisTrace, HashSet <Bus> busesOnPath)
{
//start at FromBus, take a step away from FromBus.
//If we're at the source, add the path that we took to BusesOnRouteToSource.
//If we're at a dead-end, then stop tracing this branch.
//If we hit a bus that's already on the route, then terminate and add the branch.
var connectedBuses = FromBus.ConnectedTo.OfType <Line>().Select(line => line.ConnectedTo.OfType <Bus>().Except(FromBus.Yield()).Single()) //all the buses neighbouring this one
.Except(busesInThisTrace) //exclude any buses we've already touched in this trace
;
foreach (var bus in connectedBuses)
{
if (busesOnPath.Contains(bus)) //we're connected to the target bus. no further processing required on this branch.
{
busesOnPath.UnionWith(busesInThisTrace.Except(BusThatStartedItAll.Yield()));
continue;
}
else
{
//keep searching!
HashSet <Bus> NextStepTraceList;
if (connectedBuses.Count() == 1) //if this is the only possible way forward, then just keep using the same thingy.
{
NextStepTraceList = busesInThisTrace;
}
else
{
NextStepTraceList = new HashSet <Bus>(busesInThisTrace);
}
NextStepTraceList.Add(bus);
TraceToSource(bus, BusThatStartedItAll, NextStepTraceList, busesOnPath);
}
}
}
private static void _traceWithoutCrossingBuses(Bus FromBus, HashSet <Bus> ExcludeList, HashSet <Bus> busesInThisTrace, HashSet <Bus> busesOnPath)
{
var connectedBuses = FromBus.ConnectedTo.OfType <Line>().Select(line => line.ConnectedTo.OfType <Bus>().Except(FromBus.Yield()).Single()) //all the buses neighbouring this one
.Except(busesInThisTrace) //exclude any buses we've already touched in this trace
;
if (connectedBuses.Count() == 0)
{
busesOnPath.UnionWith(busesInThisTrace);
return;
}
foreach (var bus in connectedBuses)
{
if (ExcludeList.Contains(bus)) //we're connected to the target bus. end the thread.
{
continue;
}
else
{
//keep searching!
HashSet <Bus> NextStepTraceList;
if (connectedBuses.Count() == 1) //if this is the only possible way forward, then just keep using the same thingy.
{
NextStepTraceList = busesInThisTrace;
}
else
{
NextStepTraceList = new HashSet <Bus>(busesInThisTrace);
}
NextStepTraceList.Add(bus);
_traceWithoutCrossingBuses(bus, ExcludeList, NextStepTraceList, busesOnPath);
}
}
}
