private AVL_Node <T> Rotate(AVL_Node <T> x, Direction direction)
{
AVL_Node <T> y;
if (direction == Direction.Left) // left
{
if (x == null || x.Rigth == null)
{
return(x);
}
y = x.Rigth;
x.Rigth = y.Left;
y.Left = x;
}
else // right
{
if (x == null || x.Left == null)
{
return(x);
}
y = x.Left;
x.Left = y.Rigth;
y.Rigth = x;
}
x.Update();
y.Update();
return(y);
}
private AVL_Node <T> Insert(AVL_Node <T> x, T item)
{
if (x == null)
{
x = new AVL_Node <T> {
Key = item, Height = 1, Size = 1, Left = null, Rigth = null
};
Count++;
}
else
{
if (item.CompareTo(x.Key) == 0)
{
return(x);
}
if (item.CompareTo(x.Key) < 0)
{
x.Left = Insert(x.Left, item);
}
else
{
x.Rigth = Insert(x.Rigth, item);
}
x = Balance(x);
}
return(Balance(x));
}
private AVL_Node <T> Balance(AVL_Node <T> x)
{
x.Update();
if (x.Balance_Factor > 1)
{
if (x.Rigth.Balance_Factor <= 0)
{
x.Rigth = Rotate(x.Rigth, Direction.Rigth);
}
x = Rotate(x, Direction.Left);
}
else
if (x.Balance_Factor < -1)
{
if (x.Left.Balance_Factor >= 0)
{
x.Left = Rotate(x.Left, Direction.Left);
}
x = Rotate(x, Direction.Rigth);
}
x.Update();
return(x);
}
/// <summary>
/// Removes the first occurrence of a specific object from the <see cref="T:System.Collections.Generic.ICollection`1" />.
/// </summary>
/// <returns>
/// true if <paramref name="item" /> was successfully removed from the <see cref="T:System.Collections.Generic.ICollection`1" />; otherwise, false. This method also returns false if <paramref name="item" /> is not found in the original <see cref="T:System.Collections.Generic.ICollection`1" />.
/// </returns>
/// <param name="item">The object to remove from the <see cref="T:System.Collections.Generic.ICollection`1" />.</param>
/// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1" /> is read-only.</exception>
public bool Remove(T item)
{
AVL_Node <T> temp;
if (Contains(item, out temp))
{
C_Root = Remove(C_Root, item);
return(true);
}
return(false);
}
private AVL_Node <T> Remove(AVL_Node <T> x, T item)
{
if (x == null)
{
return(x);
}
if (x.Key.CompareTo(item) == 0)
{
if (x.Left == null && x.Rigth == null)
{
return(null);
}
if (x.Left != null && x.Rigth == null)
{
return(x.Left);
}
if (x.Left == null && x.Rigth != null)
{
return(x.Rigth);
}
var t = x.Rigth;
var p = x;
while (t.Left != null)
{
p = t;
t = t.Left;
}
if (p == x)
{
return(x.Rigth);
}
p.Left = t.Rigth;
t.Rigth = x.Rigth;
t.Left = x.Left;
return(t);
}
if (x.Key.CompareTo(item) > 0)
{
x.Left = Remove(x.Left, item);
}
else
{
x.Rigth = Remove(x.Rigth, item);
}
return(Balance(x));
}
/// <summary>
/// Get max valur of tree
/// </summary>
/// <returns></returns>
public T Max()
{
if (C_Root == null)
{
throw new InvalidOperationException("The tree is empty");
}
AVL_Node <T> x = C_Root;
while (x.Rigth != null)
{
x = x.Rigth;
}
return(x.Key);
}
///<summary>
///</summary>
///<param name="item"></param>
///<returns></returns>
public AVL_Node <T> Contains(T item)
{
AVL_Node <T> x = C_Root;
for (; ;)
{
if (x == null)
{
return(null);
}
if (item.CompareTo(x.Key) == 0)
{
return(x);
}
x = item.CompareTo(x.Key) < 0 ? x.Left : x.Rigth;
}
}
///<summary>
///Determine if a item is in tree
///</summary>
///<param name="item">Item to searsh</param>
///<param name="output">the node that contain the item if the item is on </param>
///<returns></returns>
public bool Contains(T item, out AVL_Node <T> output)
{
output = Contains(item);
return(output == null ? false : true);
}