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);
}
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));
}
/// <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))
{
root = Remove(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));
}
public AVL_Node <T> Contains(T item)
{
AVL_Node <T> x = 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;
}
}
public bool Contains(IComparable item, Func <T, IComparable> func, out AVL_Node <T> output)
{
AVL_Node <T> x = root;
for (; ;)
{
if (x == null)
{
output = null;
return(false);
}
if (item.CompareTo(func(x.Key)) == 0)
{
output = x;
return(true);
}
x = item.CompareTo(func(x.Key)) < 0 ? x.Left : x.Rigth;
}
}
/// <summary>
/// Removes all items from the <see cref="T:System.Collections.Generic.ICollection`1" />.
/// </summary>
/// <exception cref="T:System.NotSupportedException">The <see cref="T:System.Collections.Generic.ICollection`1" /> is read-only. </exception>
public void Clear()
{
root = null;
Count = 0;
}
public bool Contains(T item, out AVL_Node <T> output)
{
output = Contains(item);
return(output == null ? false : true);
}
/// <summary>
/// Adds an item to the <see cref="T:System.Collections.Generic.ICollection`1" />.
/// </summary>
/// <param name="item">The object to add to 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 void Add(T item)
{
root = Insert(root, item);
}
public AVL_Tree()
{
root = null;
}