（1）一个理发店接待室有n张椅子，工作室有1张椅子；

（2）没有顾客时，理发师睡觉；

（3）第一个顾客来到时，必须将理发师唤醒；

（4）顾客来时如果还有空座的话，他就坐在一个座位上等待；

（5）如果顾客来时没有空座位了，他就离开，不理发了；

（6）当理发师处理完所有顾客，而又没有新顾客来时，他又开始睡觉。

用条件变量实现(3张椅子)

-(1) a barber shop in the reception room with n chairs, the studio has a chair　(2) no customers, the barber sleep　(3) The first customer arrives, the barber must wake up　(4) When customers come to, then if there is room, he sat on a seat to wait　(5) If the customer does not come empty seats, and he left, not a haircut　(6) When the barber finished with all customers, and and no new customers come, he began to sleep. With the condition variable implementation (three chairs)