1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
/* The Great Computer Language Shootout
http://shootout.alioth.debian.org/
contributed by Isaac Gouy
*/
public class process {
public static void main(String args[]) {
int n = Integer.parseInt(args[0]);
EndLink chainEnd = new EndLink(null, n);
chainEnd.start();
Link chain = chainEnd;
for (int i=2; i<=n; i++){
Link link = new Link(chain);
link.start();
chain = link;
}
chain.put(0);
try { chainEnd.join(); } catch (InterruptedException e){}
System.out.println(chainEnd.count);
System.exit(0);
}
}
class Link extends Thread {
Link next;
int message = -1;
boolean busy = false;
Link(Link t){
next = t;
}
public void run() {
for (;;) next.put(this.take());
}
synchronized void put(int m) {
while (busy)
try { wait(); } catch (InterruptedException e){}
busy = true;
message = m;
notifyAll();
while (message != -1)
try { wait(); } catch (InterruptedException e){}
busy = false;
notifyAll();
}
synchronized int take() {
while (message == -1)
try { wait(); } catch (InterruptedException e){}
int m = message;
message = -1;
notifyAll();
return m+1;
}
}
class EndLink extends Link {
public int count = 0;
private int finalcount;
EndLink(Link t, int i){
super(t);
finalcount = i;
}
public void run() {
do
count += this.take();
while (count < finalcount);
}
}
// vim: set ts=4 ft=java
|
