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/**
* The Computer Language Benchmarks Game
* http://shootout.alioth.debian.org/
* contributed by Klaus Friedel
*/
import java.util.*;
public class threadring {
public static long startTime;
public static final int THREAD_COUNT = 503;
// The scheduler for cooperative Multithreading
static class Scheduler extends Thread{
private final List<CooperativeThread> threads = Collections.synchronizedList(new ArrayList<CooperativeThread>());
private int rrIndex = -1;
public void start(CooperativeThread t){
threads.add(t);
}
public void run() {
for(;;){ // Scheduler will run foerever
CooperativeThread nextThread;
synchronized (threads){
rrIndex++;
if(rrIndex >= threads.size()) rrIndex = 0;
nextThread = threads.get(rrIndex);
}
nextThread.handleMessage();
}
}
}
static abstract class CooperativeThread{
public abstract void handleMessage();
}
static class MessageThread extends CooperativeThread{
MessageThread nextThread;
String name;
Integer msg;
public MessageThread(MessageThread nextThread, int name) {
this.name = "" + name;
this.nextThread = nextThread;
}
public void handleMessage(){
if(msg == null) return;
if(msg == 0){
System.out.println(getName());
System.exit(0);
}
nextThread.put(msg - 1);
msg = null;
}
void put(Integer message){
msg = message;
}
String getName() {
return name;
}
}
public static void main(String args[]) throws Exception{
int hopCount = Integer.parseInt(args[0]);
MessageThread thread = null;
MessageThread last = null;
for (int i = THREAD_COUNT; i >= 1 ; i--) {
thread = new MessageThread(thread, i);
if(i == THREAD_COUNT) last = thread;
}
// close the ring:
last.nextThread = thread;
Scheduler scheduler = new Scheduler();
// start all Threads
MessageThread t = thread;
do{
scheduler.start(t);
t = t.nextThread;
}while(t != thread);
scheduler.start();
// inject message
thread.put(hopCount);
}
}
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