public static int FindIndex(Listy listy, int x)
{
int left = 0;
int right = 1;
while (listy.ElementAt(right) != -1)
{
right = right * 2;
}
return(FindIndex(listy, left, right, x));
}
public static int FindIndex(Listy listy, int left, int right, int x)
{
if (left > right)
{
return(-1);
}
int mid = (left + right) / 2;
if (listy.ElementAt(mid) == x)
{
return(mid);
}
if (listy.ElementAt(mid) == -1 || listy.ElementAt(mid) > x)
{
return(FindIndex(listy, left, mid - 1, x));
}
return(FindIndex(listy, mid + 1, right, x));
}
public static int FindIndexIterative(Listy listy, int left, int right, int x)
{
while (left <= right)
{
int mid = (left + right) / 2;
if (listy.ElementAt(mid) == x)
{
return(mid);
}
if (listy.ElementAt(mid) == -1 || listy.ElementAt(mid) > x)
{
right = mid - 1;
}
else
{
left = mid + 1;
}
}
return(-1);
}
