数据结构作业　　某商场有一个100个车位的停车场，当车位未满时，等待的车辆可以进入并计时；当车位已满时，必须有车辆离开，等待的车辆才能进入；当车辆离开时计算停留的的时间，并且按照每小时1元收费。

汽车的输入信息格式可以是（进入/离开，车牌号，进入/离开时间），要求可以随时显示停车场内的车辆信息以及收费历史记录。

-a mall with a 100 parking spaces, while parking is not full, the vehicles can enter and wait time　when parking is full, you must leave a vehicle, waiting for vehicles to enter　when the vehicle left the residence when calculating of time, and in accordance with fee of $ 1 per hour. Car format can be input (enter/leave, license plate number, enter/leave time), required parking lot at any time within the vehicle information display, and charging history.