/// <summary>
/// Corects tree.
/// </summary>
/// <param name="node">Start fom this node.</param>
private void RepairTree(AVLNode node)
{
AVLNode temp = node;
//if (node == this.rootNode)
//{
// return;
//}
while (temp.BalanceFactor <= 1 && temp.BalanceFactor >= -1)
{
if (temp.ParentNode != null)
{
this.RepairTree(temp.ParentNode);
}
return;
}
if (temp.BalanceFactor > 1)
{
if (temp.LeftNode.BalanceFactor > -1)
{
temp.RotateRight(this);
RepairTree(temp);
return;
}
temp.LeftNode.RotateLeft(this);
temp.RotateRight(this);
return;
}
if (temp.RightNode.BalanceFactor < 1)
{
temp.RotateLeft(this);
return;
}
temp.RightNode.RotateRight(this);
temp.RotateLeft(this);
return;
}
public void RotateLeft_FullTree()
{
var node = new AVLNode <int>(100);
node.Left = new AVLNode <int>(50);
node.Right = new AVLNode <int>(150);
node.Left.Left = new AVLNode <int>(25);
node.Left.Right = new AVLNode <int>(75);
node.Right.Left = new AVLNode <int>(125);
node.Right.Right = new AVLNode <int>(175);
node = node.RotateLeft();
Assert.AreEqual <int>(150, node.Value);
Assert.AreEqual <int>(175, node.Right.Value);
Assert.AreEqual <int>(100, node.Left.Value);
Assert.AreEqual <int>(125, node.Left.Right.Value);
Assert.AreEqual <int>(50, node.Left.Left.Value);
Assert.AreEqual <int>(25, node.Left.Left.Left.Value);
Assert.AreEqual <int>(75, node.Left.Left.Right.Value);
}
public void RotateLeft_FullTree()
{
var node = new AVLNode<int>(100);
node.Left = new AVLNode<int>(50);
node.Right = new AVLNode<int>(150);
node.Left.Left = new AVLNode<int>(25);
node.Left.Right = new AVLNode<int>(75);
node.Right.Left = new AVLNode<int>(125);
node.Right.Right = new AVLNode<int>(175);
node = node.RotateLeft();
Assert.AreEqual<int>(150, node.Value);
Assert.AreEqual<int>(175, node.Right.Value);
Assert.AreEqual<int>(100, node.Left.Value);
Assert.AreEqual<int>(125, node.Left.Right.Value);
Assert.AreEqual<int>(50, node.Left.Left.Value);
Assert.AreEqual<int>(25, node.Left.Left.Left.Value);
Assert.AreEqual<int>(75, node.Left.Left.Right.Value);
}
/// <summary>
/// Removes the elemet from tree.
/// </summary>
/// <param name="item">Key Value pair of the elemet.</param>
/// <returns>True if removed.</returns>
public bool Remove(KeyValuePair <TKey, TValue> item)
{
AVLNode temp = this.rootNode;
while (temp != null)
{
switch (item.Key.CompareTo(temp.NodeKey))
{
case -1:
temp = temp.LeftNode;
break;
case 1:
temp = temp.RightNode;
break;
default:
{
if (temp.IsLeaf)
{
if (temp.ParentNode.LeftNode == temp)
{
temp.ParentNode.LeftNode = null;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
temp.ParentNode.RightNode = null;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
else if (temp.LeftNode == null)
{
temp.RightNode.ParentNode = temp.ParentNode;
if (temp.ParentNode.LeftNode == temp)
{
temp.ParentNode.LeftNode = temp.RightNode;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
temp.ParentNode.RightNode = null;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
else if (temp.RightNode == null)
{
temp.LeftNode.ParentNode = temp.ParentNode;
if (temp.ParentNode.LeftNode == temp)
{
temp.ParentNode.LeftNode = temp.LeftNode;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
temp.ParentNode.RightNode = null;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
else
{
temp.RotateLeft(this);
temp.ParentNode.LeftNode = temp.LeftNode;
temp.LeftNode.ParentNode = temp.ParentNode;
this.RepairTree(temp.ParentNode);
nodeCount--;
isModfied = true;
return(true);
}
}
}
}
return(false);
}