/// <summary>
/// Delete the node from the tree.
/// Update the related wires, and update the median.
/// According to the book page 221 it's O(h)
/// </summary>
/// <param name="node">Node for delete</param>
public void Delete(T node)
{
if (node == null)
{
return;
}
var deletedTheOldMedian = false;
UpdateWiresRelatedToRemovedNode(node);
// If we delete the current median, the counters are already updated
// so we can update it now.
if (node.Id == Median.Id)
{
UpdateMedianAfterMedianDelete();
deletedTheOldMedian = true;
}
AbstractNode nodeForRemove, nextNode = null;
if (!node.HasALeftChild() || !node.HasARightChild())
{
nodeForRemove = node;
}
else
{
nodeForRemove = node.GetSuccessor();
}
if (nodeForRemove.HasALeftChild())
{
nextNode = nodeForRemove.LeftChild;
}
else if (nodeForRemove.HasARightChild())
{
nextNode = nodeForRemove.RightChild;
}
if (nextNode != null)
{
nextNode.Parent = nodeForRemove.Parent;
}
if (nodeForRemove.Parent == null)
{
Root = nextNode as T;
}
else
{
if (nodeForRemove.Id == nodeForRemove.Parent.LeftChild.Id)
{
nodeForRemove.Parent.LeftChild = nextNode;
// If after this change, the parent gets a "null child"
// instead of the delete node, wire it to predecessor
if (nodeForRemove.Parent.LeftChild == null)
{
nodeForRemove.Parent.LeftChild = nodeForRemove.Parent.GetPredecessor();
}
}
else
{
nodeForRemove.Parent.RightChild = nextNode;
// If after this change, the parent gets a "null child"
// instead of the delete node, wire it to successor
if (nodeForRemove.Parent.RightChild == null)
{
nodeForRemove.Parent.RightChild = nodeForRemove.Parent.GetSuccessor();
}
}
}
if (nodeForRemove.Id != node.Id)
{
node.Clone(nodeForRemove);
}
// If we deleted another node(not the median), update the median
// if needed
if (!deletedTheOldMedian)
{
UpdateMedianAfterRemoveNotMedian(node);
}
}
protected AbstractNode(int id)
{
Id = id;
Parent = null;
}
