设停车场是一个可停放n辆车的狭长通道，且只有一个大门可供汽车进出。在停车场内，汽车按到达的先后次序，由北向南依次排列（假设大门在最南端）。-Parking lots is a car parked n the narrow channel, and only one gate for vehicle access. In the parking lot, the car arrived at the order, from north to south in order of priority (assuming the door at the southern tip.)