int waiting=0;
barber:
do{
wait(working);
signal(barber);
…
//理发
…
}while(true);

customer:
do{
wait(mutex);
if(waiting signal(working;
waiting++;
signal(mutex);
wait(barber);
wait(mutex);
waiting--;
wait(mutex);
…
//理发
…
}
else{
signal(mutex);
}
}while(true);