有一个理发师，一把理发椅和n把提供给等候理发的顾客座的椅子。如果没有顾客，则理发师便在理发椅子上睡觉；当第一个顾客到来时，必须唤醒该理发师进行理发；如果理发师正在理发时又有顾客到来，则如果有空椅子可坐，他就坐下来等待，如果没有空椅子，他就离开理发店。
为理发师和顾客各编一段程序描述他们的行为，要求不能带有竞争条件，试用P、V操作实现。(There was a barber, a barber's chair and a chair n offered to the customer waiting for the haircut. If no customers, the barber would sleep in the barber chair; when the customer comes first, must arouse the barber for a haircut; if the barber is the barber again when customers come, if the empty chair sitting, he sat down to wait, if there is no empty seat, he left the barber shop.
Prepare a program for barbers and customers to describe their actions, requiring no competition, and trial P and V operations.)