private IEnumerable <Route> Compute(Request request)
{
var town = _towns.FirstOrDefault(a => a.Name == request.From);
_queue.Enqueue(town, 0, Route.Empty);
while (_queue.HasData)
{
_queue.Dequeue();
foreach (var neighbor in _queue.CurrentTown.Neighbors)
{
town = neighbor.Key;
int distance = neighbor.Value;
if ((_queue.CurrentRoute.Distance + distance) >= (request.DistanceLessThan ?? int.MaxValue))
{
continue;
}
if (_queue.CurrentRoute.Stops > (request.MaxStop ?? int.MaxValue))
{
continue;
}
if (town.Name == request.To)
{
if (request.AllowCircularRoute)
{
_queue.Enqueue(town, distance, _queue.CurrentRoute);
}
yield return(_queue.CurrentRoute.NewRouteTo(request.To, distance));
}
else
{
if (_queue.CurrentRoute.TownHasVisited(town) && !request.AllowCircularRoute)
{
continue;
}
_queue.Enqueue(town, distance, _queue.CurrentRoute);
}
}
}
}
