program sample;
    var c1,c2:integer;
    procedure p1
        begin
        repeat
            other section 1;
            repeat
            c1 = 1-c2;
            until c2!=0
            critical section;//临界区
            c1 = 1;
        until false
        end
    procedure p2
        begin
        repeat
            other section 2;
            repeat
            c2 = 1-c1;
            until c1!=0
            critical section;//临界区
            c2 = 1;
        until false
        end
    begin 
        c1 = 1;
        c2 = 1;    
        cobegin    
            p1;    
            p2;//进程p1,p2并行执行
        end

var s=1,s0=1,s1=1,s2=1:semaphore;
var count0=0,count1=0,count2=0;

cobegin
process videoshow0 //vcd_id = 0
begin
    repeat
        p(s0);
        count0 = count0 +1;
        if(count0=1) p(s);
        v(s0);    
        看影片；
        p(s0);
        count0 = count0 -1;
        if(count0=1) v(s);
        v(s0);
    until false
end

process videoshow1 //vcd_id = 1
begin
    repeat
        p(s1);
        count1 = count1 +1;
        if(count1=1) p(s);
        v(s1);    
        看影片；
        p(s1);
        count1 = count1 -1;
        if(count1=1) v(s);
        v(s1);
    until false
end
process videoshow2 //vcd_id =2
begin
    repeat
        p(s2);
        count2 = count2 +1;
        if(count2=1) p(s);
        v(s2);    
        看影片；
        p(s2);
        count1 = count1 -1;
        if(count2=1) v(s);
        v(s2);
    until false
end
coend

var mutex=1,count=1:semaphore;

cobegin
process Readeri(i=1,2)
begin
    repeat
        进入图书馆；
        p(count);
        p(mutex);
        i = 获取座位号；
        登记i项表目(名字，座位号);
        v(mutex);
        坐下阅读；
        p(mutex);
        消去登记项（名字，座位号）
        v(mutex);
        v(count);
        离开；
    until false
end

var s1=1,s0=0:semaphore;

cobegin
process p1
begin
    repeat
        p(s1);
        捡白子；
        v(s2);
    until false
end

process p2
begin
    repeat
        p(s2);
        捡黑子；
        v(s1);
    until false
end

var sa=1,sb=1,mutex=1,c1=0,c2=0,k1=0,k2=0:semaphore;

cobegin

process 甲
begin
    L1:p(mutex);
        p(sa);
        c1 = c1 +1;
        v(sa);
        if(c1<=100) then
        begin
            从标志为“B"且不为”Sb"或无标识的毕业生队列中选第i个学生将学生i标识为"A"和"sa"
        end
        v(mutex);
        面试;
        p(mutex);
        if 合格 then
        begin
            k1 = k1 +1;
            if(学生i的标识不含"B") then 
            begin
                p(sb);            
                c2 = c2+1;
                v(sb);
                将学生i从队列上摘除；
            end
            else
                将学生 i从队列上摘除；
        else
        if(学生i的标识含“B”）then 
            将学生i从队列上摘除
        else
            取消学生i的"sa"标识；
        v(mutex);
        if(k1<10) and (c1<100) then goto L1
end
        v(s2);
    until false
end

process 乙
begin
    L2:p(mutex);
        p(sa);
        c2 = c2 +1;
        v(sb);
        if(c2<=100) then
        begin
            从标志为“A"且不为”Sa"或无标识的毕业生队列中选第i个学生将学生i标识为"B"和"sb"
        end
        v(mutex);
        面试;
        p(mutex);
        if 合格 then
        begin
            k2 = k2 +1;
            if(学生i的标识不含"A") then 
            begin
                p(sa);            
                c1 = c1+1;
                v(sa);
                将学生i从队列上摘除；
            end
            else
                将学生 i从队列上摘除；
        else
        if(学生i的标识含“A”）then 
            将学生i从队列上摘除
        else
            取消学生i的"sb"标识；
        v(mutex);
        if(k2<10) and (c2<100) then goto L2
end
        v(s2);
    until false
end