说明：  Parking Lot Simulation： Parking lot attendants often park cars bumper-to-bumper, several cars deep. This maximizes the number of cars they can fit into a parking lot at the expense of complicating the process of retrieving someone s car when they want to leave. Consider the case of a person wanting to leave the parking lot but their car is parked in the back of a row of cars. In this case, all the cars parked in front of this person s car must be temporarily moved to allow this person to leave.
(Parking Lot Simulation: Parking lot attendants often park cars bumper-to-bumper, several cars deep. This maximizes the number of cars they can fit into a parking lot at the expense of complicating the process of retrieving someone s car when they want to leave . Consider the case of a person wanting to leave the parking lot but their car is parked in the back of a row of cars. In this case, all the cars parked in front of this person s car must be temporarily moved to allow this person to leave.)