public bool Insert(T data)
{
/* if (!(data is ValueType) && EqualityComparer<T>.Default.Equals(data, default(T)) )
* {
* return false;
* }
* else */if (m_Root == m_Bottom)
{
// create root node
m_Root = CreateNode(data);
return(true);
}
else
{
Node currentNode = m_Root;
Node parent = null;
int comparisonResult = 1; // initial value for loop condition to hold
// store traversal history in stack
Stack <TraversalHistory> nodeStack = new Stack <TraversalHistory>((int)Math.Ceiling(Math.Log(Count + 1, 2)) + 1);
nodeStack.Push(new TraversalHistory(currentNode, parent, TraversalHistory.ECHILDSIDE.ISROOT));
while (currentNode != m_Bottom)
{
parent = currentNode;
comparisonResult = CompareTo(data, currentNode.Data, COMPARISON_TYPE.INSERT);
TraversalHistory histEntry;
// switch between left or right
if (comparisonResult <= 0)
{
currentNode = currentNode.Left;
histEntry = new TraversalHistory(currentNode, parent, TraversalHistory.ECHILDSIDE.LEFT);
nodeStack.Push(histEntry);
}
else if (comparisonResult > 0)
{
currentNode = currentNode.Right;
histEntry = new TraversalHistory(currentNode, parent, TraversalHistory.ECHILDSIDE.RIGHT);
nodeStack.Push(histEntry);
}
}
// check if traversed until bottom
bool didInsert = false;
if (nodeStack.Pop().node == m_Bottom) // This node must be m_Bottom.
{
// use last comparison result and parent to insert new node
if (comparisonResult <= 0)
{
parent.Left = CreateNode(data);
didInsert = true;
}
else if (comparisonResult > 0)
{
parent.Right = CreateNode(data);
didInsert = true;
}
}
// pop history stack and change shift tree when necessary
while (nodeStack.Count != 0)
{
TraversalHistory t = nodeStack.Pop();
Node n = t.node;
n = Skew(n, t.parentNode, t.side);
Split(n, t.parentNode, t.side);
}
// return whether a node was inserted
return(didInsert);
}
}
public bool Delete(T data)
{
if (m_Root == m_Bottom /*|| EqualityComparer<T>.Default.Equals(data, default(T)) */)
{
return(false);
}
Node currentNode = m_Root;
Node parent = null;
Node deleted = m_Bottom;
Stack <TraversalHistory> nodeStack = new Stack <TraversalHistory>((int)Math.Ceiling(Math.Log(Count + 1, 2)) + 1);
nodeStack.Push(new TraversalHistory(currentNode, parent, TraversalHistory.ECHILDSIDE.ISROOT));
while (currentNode != m_Bottom)
{
parent = currentNode;
TraversalHistory hist;
int comparisonResult = CompareTo(data, currentNode.Data, COMPARISON_TYPE.DELETE);
if (comparisonResult < 0)
{
currentNode = currentNode.Left;
hist = new TraversalHistory(currentNode, parent, TraversalHistory.ECHILDSIDE.LEFT);
}
else
{
deleted = currentNode;
currentNode = currentNode.Right;
hist = new TraversalHistory(currentNode, parent, TraversalHistory.ECHILDSIDE.RIGHT);
}
nodeStack.Push(hist);
}
bool didDelete = false;
if (deleted != m_Bottom && CompareTo(data, deleted.Data, COMPARISON_TYPE.DELETE) == 0)
{
if (nodeStack.Pop().node != m_Bottom) // Pop since the last entry is m_Bottom
{
throw new Exception("First node in traversal history was not Bottom!");
}
TraversalHistory lastHist = nodeStack.Pop();
Node last = lastHist.node; // This is the node that is leftmost of the node that we want to delete.
if (last.Left != m_Bottom)
{
throw new Exception("Last has a left child that is not Bottom!");
}
deleted.Data = last.Data;
Node copy = last.Right;
if (copy != m_Bottom)
{
last.Data = copy.Data;
last.Left = copy.Left;
last.Right = copy.Right;
last.Level = copy.Level;
// Destroy the node
copy.Left = null;
copy.Right = null;
copy.Data = default(T);
}
else
{
if (lastHist.side == TraversalHistory.ECHILDSIDE.LEFT)
{
lastHist.parentNode.Left = m_Bottom;
}
else if (lastHist.side == TraversalHistory.ECHILDSIDE.RIGHT)
{
lastHist.parentNode.Right = m_Bottom;
}
else
{
m_Root = m_Bottom;
}
}
--Count;
didDelete = true;
}
// pop history stack and change tree when necessary
while (nodeStack.Count != 0)
{
TraversalHistory t = nodeStack.Pop();
Node n = t.node;
if (n.Left.Level < n.Level - 1 || n.Right.Level < n.Level - 1)
{
--n.Level;
if (n.Right.Level > n.Level)
{
n.Right.Level = n.Level;
}
n = Skew(n, t.parentNode, t.side);
n.Right = Skew(n.Right, n, TraversalHistory.ECHILDSIDE.RIGHT);
n.Right.Right = Skew(n.Right.Right, n.Right, TraversalHistory.ECHILDSIDE.RIGHT);
n = Split(n, t.parentNode, t.side);
n.Right = Split(n.Right, n, TraversalHistory.ECHILDSIDE.RIGHT);
}
}
return(didDelete);
}
