设停车场内只有一个可停放辆汽车的狭长通道且只有一个大门可供汽车进出。汽车在停车场内按车辆到达时的先后顺序依次由北向南排列（大门在最南端，最先到达的第一辆车停放在车场的最北端若车场内已停满N辆车，则最后来的汽车只能在门外的便道上等候，一旦停车场内有车开走，则排在便道上的第一辆车可开入；当停车场内某辆车要离开时由于停车场是狭长的通道，在它之后开入车场的车辆必须先退出车场为它让路，待该车开出大门外后，为它让路的车辆再按原次序进入车场。在这里假设汽车不能从便道上开走。试设计一个停车场管理系统-There is only one car park for the parking of vehicles can be long and narrow and there is only one channel open to motor out of the door. Car in the parking lot with the arrival of the vehicles according to the order in which they followed north to south at the time of order (the door in the southernmost tip of the first to arrive at the first car parked in the most northern end of the depot if the car had been parked inside vehicles over N, then the last car can only wait for the sidewalk outside, once the car park a car drive away, then in the sidewalk on the first car to be opened　when parking vehicles within a certain time to leave the car park is long and narrow as a result of the channel in it into the car after the vehicle must first withdraw from the yard to make way for it to be outside the main entrance of the car out after it to make way for vehicles to enter the car and then the original sequence. Here the assumption that the vehicle can not be driven away from the sidewa