private static int TopDown(int n)
{
int[] counts = new int[n + 1];
counts[0] = 1;
return(TripleStep.TopDown(n, counts));
}
private static int TopDown(int n, int[] counts)
{
if (n < 0)
{
return(0);
}
if (counts[n] == 0)
{
counts[n] = TripleStep.TopDown(n - 1, counts)
+ TripleStep.TopDown(n - 2, counts)
+ TripleStep.TopDown(n - 3, counts);
}
return(counts[n]);
}