Store FleetState as a vector instead of a map?

[matdahl]

In the current Python version of the FleetState, the VehicleStates are stored in a dictionary/map.

However, if I see it correctly, there are no vehicles removed during a simulation run. Thus, instead of putting the VehicleStates into a map that requires a search for the correct index each time a VehicleState is accessed, one could also store them into a vector, using the index of the vehicle as its vehicle_id (thus, all vehicle_ids would be in [0,numVehicles-1] )

In this case, the access of a random VehicleState would be (in C++) a trivial operation, as the program immediately knows where to find the vehicle_id-th entry of a vector.

If later vehicles should be "mutable", i.e. put out of service e.g. for maintenance work, one could add a flag inService to VehicleState to tell the dispatcher, whether this vehicle is available or not.

Or is there another reason to use a dictionary/map here?