private bool RemoveNode(AVLTreeNode <T> current)
{
if (current == null || current._tree != this)
{
return(false);
}
var parent = current.Parent;
//Case: no right child
if (current == Head)
{
Head = null;
}
if (current.Right == null)
{
if (parent == null)
{
Head = current.Left;
}
else
{
int compare = parent.Value.CompareTo(current.Value);
if (compare > 0)
{
parent.Left = current.Left;
}
else
{
parent.Right = current.Left;
}
}
}
//Case: the right child don't have left child
else if (current.Right.Left == null)
{
current.Right.Left = current.Left;
if (parent == null)
{
Head = current.Right;
}
else
{
int compare = parent.Value.CompareTo(current.Value);
if (compare > 0)
{
parent.Left = current.Right;
}
else
{
parent.Right = current.Right;
}
}
}
//Case: the right child has a left child
else
{
AVLTreeNode <T> leftMost = current.Right.Left;
AVLTreeNode <T> leftMostParent = current.Right;
while (leftMost.Left != null)
{
leftMostParent = leftMost;
leftMost = leftMostParent.Left;
}
leftMostParent.Left = leftMost.Right;
leftMost.Left = current.Left;
leftMost.Left = current.Right;
if (parent == null)
{
Head = leftMost;
}
else
{
int compare = parent.Value.CompareTo(current.Value);
if (compare > 0)
{
parent.Left = leftMost;
}
else
{
parent.Right = leftMost;
}
}
}
return(true);
}