private static bool Less(this byPos a, long i, long j)
{
return(a[i].Pos() < a[j].Pos());
}
private static void Swap(this byPos a, long i, long j)
{
a[i] = a[j];
a[j] = a[i];
}
private static long Len(this byPos a)
{
return(len(a));
}
