public TValue this[TKey key]
{
get
{
return(Search(key));
}
set
{
NodeAVL <TKey, TValue> current = root;
while (current != null)
{
if (key.Equals(current.Key))
{
current.Value = value;
}
else if (key.CompareTo(current.Key) > 0)
{
current = current.RightChild;
}
else
{
current = current.LeftChild;
}
}
if (current == null)
{
throw new Exception("That key doesn't exist.");
}
}
}
public void Balance(NodeAVL <TKey, TValue> node)
{
if (node == null)
{
return;
}
if (node.BalancFactor < -1 && node.RightChild.BalancFactor == -1)
{
LeftRotation(node.RightChild.RightChild);
}
else if (node.BalancFactor < -1 && node.RightChild.BalancFactor == 1)
{
RightRotation(node.RightChild.LeftChild);
}
else if (node.BalancFactor < -1)
{
LeftRotation(node.RightChild);
}
else if (node.BalancFactor > 1 && node.LeftChild.BalancFactor == -1)
{
LeftRotation(node.LeftChild.RightChild);
}
else if (node.BalancFactor > 1 && node.LeftChild.BalancFactor == 1)
{
RightRotation(node.LeftChild.LeftChild);
}
else if (node.BalancFactor > 1)
{
RightRotation(node.LeftChild);
}
Balance(node.Parent);
}
public bool Contains(KeyValuePair <TKey, TValue> item)
{
NodeAVL <TKey, TValue> current = this.root;
while (current != null)
{
if (current.Key.Equals(item.Key))
{
if (item.Value.Equals(current.Value))
{
return(true);
}
else
{
return(false);
}
}
else if (current.Key.CompareTo(item.Key) > 0)
{
current = current.LeftChild;
}
else
{
current = current.RightChild;
}
}
return(false);
}
public void Add(TKey key, TValue value)
{
NodeAVL <TKey, TValue> node = new NodeAVL <TKey, TValue>(key, value);
NodeAVL <TKey, TValue> current;
if (this.root == null)
{
this.root = node;
}
else
{
current = this.root;
while (current.LeftChild != null && current.RightChild != null)
{
if (current.Key.CompareTo(key) > 0)
{
current = current.LeftChild;
}
else
{
current = current.RightChild;
}
}
if (current.Key.CompareTo(key) > 0 && current.LeftChild == null)
{
current.LeftChild = node;
node.Parent = current;
return;
}
else if (current.Key.CompareTo(key) <= 0 && current.RightChild == null)
{
current.RightChild = node;
node.Parent = current;
return;
}
else if (current.Key.CompareTo(key) > 0 && current.LeftChild != null)
{
current = current.LeftChild;
}
else
{
current = current.RightChild;
}
if (current.Key.CompareTo(key) > 0)
{
current.LeftChild = node;
node.Parent = current;
current = node;
RightRotation(current);
}
else
{
current.RightChild = node;
node.Parent = current;
current = node;
LeftRotation(current);
}
}
}
public bool IsLeaf(NodeAVL <TKey, TValue> node)
{
if (node.LeftChild == null && node.RightChild == node)
{
return(true);;
}
return(false);
}
public void PrintInside(NodeAVL <TKey, TValue> element)
{
if (element != null)
{
Console.WriteLine(element.Value + " " + element.Key + " " + element.Height + " " + element.BalancFactor);
Console.WriteLine("Left Child: ");
PrintInside(element.LeftChild);
Console.WriteLine("Right Child: ");
PrintInside(element.RightChild);
}
}
public void RightRotation(NodeAVL <TKey, TValue> current)
{
if (current == null || current.Parent == null)
{
return;
}
if (current.Parent.Parent == null)
{
current.Parent.LeftChild = current.RightChild;
current.RightChild = current.Parent;
current.Parent = null;
current.RightChild.Parent = current;
root = current;
}
else if (current.Parent.Parent.LeftChild == current.Parent)
{
current = current.Parent;
if (current.Parent != root)
{
if (current.Parent.Parent.LeftChild == current.Parent)
{
current.Parent.Parent.LeftChild = current;
}
else
{
current.Parent.Parent.RightChild = current;
}
current.Parent.LeftChild = current.RightChild;
current.RightChild = current.Parent;
current.Parent = current.Parent.Parent;
current.RightChild.Parent = current;
}
else
{
current.Parent.LeftChild = current.RightChild;
current.RightChild = current.Parent;
current.Parent = current.Parent.Parent;
current.RightChild.Parent = current;
root = current;
}
}
else
{
current.Parent.Parent.RightChild = current;
current.Parent.LeftChild = current.LeftChild;
current.RightChild = current.Parent;
current.Parent = current.Parent.Parent;
current.RightChild.Parent = current;
current = current.RightChild;
LeftRotation(current);
}
}
/// <summary>
/// Method to find the value with given key.
/// It returns value if tree contains node with that , and default value otherwise.
/// </summary>
/// <param name="key"></param>
/// <returns></returns>
public TValue Search(TKey key)
{
NodeAVL <TKey, TValue> current = root;
while (current != null)
{
if (key.Equals(current.Key))
{
return(current.Value);
}
else if (key.CompareTo(current.Key) > 0)
{
current = current.RightChild;
}
else
{
current = current.LeftChild;
}
}
return(default(TValue));
}
public bool ContainsKey(TKey key)
{
NodeAVL <TKey, TValue> current = this.root;
while (current != null)
{
if (current.Key.Equals(key))
{
return(true);
}
else if (current.Key.CompareTo(key) > 0)
{
current = current.LeftChild;
}
else
{
current = current.RightChild;
}
}
return(false);
}
public NodeAVL <TKey, TValue> Delete(TKey key)
{
NodeAVL <TKey, TValue> node;
NodeAVL <TKey, TValue> current;
NodeAVL <TKey, TValue> toReturn;
if (root.Key.Equals(key))
{
if (IsLeaf(root))
{
root = null;
return(null);
}
else if (root.RightChild != null)
{
node = this.root;
current = root.RightChild;
while (current.LeftChild != null)
{
current = current.LeftChild;
}
if (current.Parent.LeftChild == current)
{
toReturn = current.Parent;
current.Parent.LeftChild = current.RightChild;
root = current;
root.RightChild = node.RightChild;
}
else
{
toReturn = root;
root = current;
root.RightChild = current.RightChild;
}
root.LeftChild = node.LeftChild;
return(toReturn);
}
else
{
root = root.LeftChild;
return(root);
}
}
else
{
current = root;
while (current != null && !current.Key.Equals(key))
{
if (current.Key.CompareTo(key) > 0)
{
current = current.LeftChild;
}
else
{
current = current.RightChild;
}
}
if (current == null)
{
return(null);
}
else if (IsLeaf(current))
{
if (current.Parent.LeftChild == current)
{
current.Parent.LeftChild = null;
}
else
{
current.Parent.RightChild = null;
}
current = current.Parent;
}
else if (current.RightChild != null && current.LeftChild != null)
{
node = current.RightChild;
while (node.LeftChild != null)
{
node = node.LeftChild;
}
toReturn = node.Parent;
current.LeftChild.Parent = node;
if (node.Parent.LeftChild == node)
{
node.Parent.LeftChild = node.RightChild;
current.RightChild.Parent = node;
node.RightChild = current.RightChild;
}
if (current.Parent.LeftChild == current)
{
current.Parent.LeftChild = node;
}
else
{
current.Parent.RightChild = node;
}
node.Parent = current.Parent;
node.LeftChild = current.LeftChild;
return(toReturn);
}
else if (current.RightChild != null)
{
if (current.Parent.LeftChild == current)
{
current.Parent.LeftChild = current.RightChild;
}
else
{
current.Parent.RightChild = current.RightChild;
}
if (current.RightChild != null)
{
current.RightChild.Parent = current.Parent;
}
return(current.Parent);
}
else
{
if (current.Parent.LeftChild == current)
{
current.Parent.LeftChild = current.LeftChild;
}
else
{
current.Parent.RightChild = current.LeftChild;
}
if (current.LeftChild != null)
{
current.LeftChild.Parent = current.Parent;
}
return(current.Parent);
}
}
return(current);
}
public void Clear()
{
root = null;
}
public AVLDictionary(TKey key, TValue value)
{
root = new NodeAVL <TKey, TValue>(key, value);
}