Google面试题（java）—有四个线程1、2、3、4。线程1的功能就是输出1，线程2的功能就是输出2，以此类推.........现在有四个文件ABCD

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class CallThread {
private static class MyRunable implements Runnable {
int index = 0;
int max = 4 * 2;
HashMap<Integer, List<Integer>> map = new HashMap<Integer, List<Integer>>();
{
for (int i = 0; i < 4; i++) {
map.put(i, new ArrayList<Integer>());
}
}
boolean isRunning = true;

public synchronized void run() {
while (true) {
int name = Integer.valueOf(Thread.currentThread().getName());
while (index % 4 != name) {
try {
this.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (!isRunning) {
return;
}
}
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
for (int i = 0, arrIndex = index; i < 4; i++ ) {
try {
if (arrIndex-- < 0) {
break;
}
List<Integer> list = map.get(i);
if (list.size() < max) {
list.add(name + 1);
}
} catch (Exception e) {
}
}
System.err.println("A:" + map.get(0));
System.err.println("B:" + map.get(1));
System.err.println("C:" + map.get(2));
System.err.println("D:" + map.get(3));
System.err.println("-----------------------");

if (map.get(map.size()-1).size() == max) {
isRunning = false;
this.notifyAll();
return;
} else {
index++;
}
this.notifyAll();
}
}

}

public static void main(String[] args) throws InterruptedException {
Runnable runable = new MyRunable();
for (int i = 0; i < 4; i++) {
Thread t = new Thread(runable);
t.setName(String.valueOf(i));
t.start();
}
}
}

1 #include <iostream>
2 #include <stdlib.h>
3 #include <pthread.h>
4 using namespace std;
5
6 pthread_mutex_t myloack=PTHREAD_MUTEX_INITIALIZER;
7 pthread_cond_t mycond=PTHREAD_COND_INITIALIZER;
8 int n=0;
9 void *ThreadFunc(void *arg)
10 {
11     int num=(int )arg;
12     for (int i = 0; i < 10; ++i)
13     {
14         pthread_mutex_lock(&myloack);
15         while (n!=num)//1号线程第一次执行时直接跳过
16             pthread_cond_wait(&mycond,&myloack);//因为多个线程共用一个条件变量，所以在田间变量被signal后，需要用while来确定是否本线程获得执行权
17
18         if (num==0)
19             cout<<"1";
20         else if(num==1)
21             cout<<"2";
22         else if(num==2)
23             cout<<"3";
24         else
25             cout<<"4"<<endl;
26         n=(n+1)%4;
27         pthread_mutex_unlock(&myloack);
28         pthread_cond_broadcast(&mycond);
29     }
30     return (void *)0;
31 }
32
33 int  main(int argc, char const *argv[])
34 {
35
36     pthread_t id[4];
37     for (int i = 0; i < 4; ++i)
38     {
39         int err=pthread_create(&id[i],NULL,ThreadFunc,(void *)i);
40         if (err!=0)
41         {
42             cout<<"create err:"<<endl;
43             exit(-1);
44         }
45
46     }
47
48     for (int i = 0; i < 4; ++i)
49     {
50         int ret=pthread_join(id[i],NULL);
51         if (ret!=0)
52         {
53             cout<<"join err:"<<endl;
54             exit(-1);
55         }
56     }
57     return 0;
58 }