/// <summary>
/// Deletes <paramref name="x"/> from this subtree.
/// </summary>
/// <param name="x">
/// The value to delete.
/// </param>
/// <remarks>
/// This method is based upon the vEB-Tree-Delete(V, x)
/// algorithm pseudocode from the CLRS book on page 554.
/// </remarks>
public void Delete(int x)
{
if (x < 0 || x >= Universe)
{
// Simply return if the value to delete is outside of
// the universe, since it can never be in this tree.
return;
}
if (Minimum == Maximum)
{
Minimum = null;
Maximum = null;
}
else if (Universe == 2)
{
Minimum = x == 0 ? 1 : 0;
Maximum = Minimum;
}
else
{
if (x == Minimum)
{
int?firstCluster = Summary.Minimum;
x = Index(firstCluster.Value, Cluster[firstCluster.Value].Minimum.Value);
Minimum = x;
}
int highX = High(x);
Cluster[highX].Delete(Low(x));
if (!Cluster[highX].Minimum.HasValue)
{
Summary.Delete(highX);
if (x == Maximum)
{
int?summaryMax = Summary.Maximum;
if (!summaryMax.HasValue)
{
Maximum = Minimum;
}
else
{
Maximum = Index(summaryMax.Value, Cluster[summaryMax.Value].Maximum.Value);
}
}
}
else if (x == Maximum)
{
Maximum = Index(highX, Cluster[highX].Maximum.Value);
}
}
}
public void Delete(uint x)
{
if (Min == Max)
{
Min = null;
Max = null;
}
else if (U == 2)
{
if (x == 0)
{
Min = 1;
}
else
{
Min = 0;
}
Max = Min;
}
else
{
if (x == Min)
{
var firstCluster = Summary.Minimum();
x = Index(firstCluster.Value, Cluster[firstCluster.Value].Minimum().Value);
Min = x;
}
Cluster[High(x)].Delete(Low(x));
if (Cluster[High(x)].Minimum() == null)
{
Summary.Delete(High(x));
if (x == Max)
{
var summaryMax = Summary.Maximum();
if (summaryMax == null)
{
Max = Min;
}
else
{
Max = Index(summaryMax.Value, Cluster[summaryMax.Value].Maximum().Value);
}
}
}
else
{
if (x == Max)
{
Max = Index(High(x), Cluster[High(x)].Maximum().Value);
}
}
}
}
