DISQUS

Since when did Google and Microsoft agree on the definition of "open"? Good luck!

No, he can't... he's limited to 500 characters.

Are all of your stories ripped off from Slashdot comments?

sorry, I'd forgotten how slow mod operator is. Even faster:

public class Chain
{
private int size;

public Chain(int size)
{
this.size = size;
}

public int kill(int nth)
{
int[] people = new int[size];
for(int i=0;i 1)
{
curCount++;
if (curCount != nth)
{
people[fillPos] = people[curPos];
fillPos++;
}
else curCount = 0;
curPos++;
if (curPos == realSize)
{
realSize -= (curPos - fillPos);
curPos = 0;
fillPos = 0;
}
}
return people[0];
}

public static void main(String[] args)
{
int ITER = 100000;
runTest(ITER);
runTest(ITER);
runTest(ITER);
runTest(ITER);
}

private static void runTest(int ITER)
{
long start = System.nanoTime();
for (int i = 0 ; i ITER ; i++)
{
Chain chain = new Chain(40);
chain.kill(3);
}
long end = System.nanoTime();
System.out.println("Time per iteration = " + ((end - start) / (ITER )) + " nanoseconds.");
}

}

I never understood why microbenchmarks are run with bad algorithms. If performance was critical, I would not write the code the way it has been written above. Also, for Java, in performance critical situations, you should run the test multiple times to see how the JIT compilation affects the performance.

Here is the code I would write for this. It works equally well in Java, C or C++.

public class Chain
{
protected static final String versionID = "@(#) $ Id: $ ";

private int size;

public Chain(int size)
{
this.size = size;
}

public int kill(int nth)
{
int[] people = new int[size];
for(int i=0;i 1)
{
curCount++;
if (curCount % nth != 0)
{
people[fillPos] = people[curPos];
fillPos++;
}
curPos++;
if (curPos == realSize)
{
realSize -= (curPos - fillPos);
curPos = 0;
fillPos = 0;
}
}
return people[0];
}

public static void main(String[] args)
{
int ITER = 100000;
runTest(ITER);
runTest(ITER);
runTest(ITER);
runTest(ITER);
}

private static void runTest(int ITER)
{
long start = System.nanoTime();
for (int i = 0 ; i ITER ; i++)
{
Chain chain = new Chain(40);
chain.kill(3);
}
long end = System.nanoTime();
System.out.println("Time per iteration = " + ((end - start) / (ITER )) + " nanoseconds.");
}

}

Testing

Ah, you didnt see it? i dont get why so many people are ignoring some great anime movies/series :