/// <summary>
/// Правый поворот
/// Зеркальное отражение метода <see cref = "LeftRotate(RBT_Node)"/>
/// </summary>
/// <param name="Y"></param>
/// <returns>void</returns>
private void RightRotate(RBT_Node Y)
{
RBT_Node X = Y.Left;
Y.Left = X.Right;
if (X.Right != null)
{
X.Right.Parent = Y;
}
if (X != null)
{
X.Parent = Y.Parent;
}
if (Y.Parent == null)
{
Root = X;
}
if (Y == Y.Parent.Right)
{
Y.Parent.Right = X;
}
if (Y == Y.Parent.Left)
{
Y.Parent.Left = X;
}
X.Right = Y;
if (Y != null)
{
Y.Parent = X;
}
}
/// <summary>
/// Левый поворот
/// Зеркальное отражение метода <see cref = "RightRotate(RBT_Node)"/>
/// </summary>
/// <param name="X"></param>
/// <returns>void</returns>
private void LeftRotate(RBT_Node X)
{
RBT_Node Y = X.Right;
X.Right = Y.Left;
if (Y.Left != null)
{
Y.Left.Parent = X;
}
if (Y != null)
{
Y.Parent = X.Parent;
}
if (X.Parent == null)
{
Root = Y;
}
if (X == X.Parent.Left)
{
X.Parent.Left = Y;
}
else
{
X.Parent.Right = Y;
}
Y.Left = X;
if (X != null)
{
X.Parent = Y;
}
}
/// <summary>
/// Удаление значения из дерева
/// </summary>
/// <param name="item"></param>
public void Delete(int key)
{
RBT_Node item = Search(key);
RBT_Node X = null;
RBT_Node Y = null;
//if (Search(key) == null) throw new ArgumentException("Элемент не найден");
if (item == null)
{
throw new ArgumentException("Элемент не найден");
}
if (item.Left == null || item.Right == null)
{
Y = item;
}
else
{
Y = TreeSuccessor(item);
}
if (Y.Left != null)
{
X = Y.Left;
}
else
{
X = Y.Right;
}
if (X != null)
{
X.Parent = Y;
}
if (Y.Parent == null)
{
Root = X;
}
else if (Y == Y.Parent.Left)
{
Y.Parent.Left = X;
}
else
{
Y.Parent.Right = X;
}
if (Y != item)
{
item.Value = Y.Value;
}
if (Y.Color == NodeColor.Black)
{
DeleteFixUp(X);
}
}
private void InsertFixUp(RBT_Node item)
{
while (item != Root && item.Parent.Color == NodeColor.Red)
{
if (item.Parent == item.Parent.Parent.Left)
{
RBT_Node Y = item.Parent.Parent.Right;
if (Y != null && Y.Color == NodeColor.Red)
{
item.Parent.Color = NodeColor.Black;
Y.Color = NodeColor.Black;
item.Parent.Parent.Color = NodeColor.Red;
item = item.Parent.Parent;
}
else
{
if (item == item.Parent.Right)
{
item = item.Parent;
LeftRotate(item);
}
item.Parent.Color = NodeColor.Black;
item.Parent.Parent.Color = NodeColor.Red;
RightRotate(item.Parent.Parent);
}
}
else
{
RBT_Node X = null;
X = item.Parent.Parent.Left;
if (X != null && X.Color == NodeColor.Black)
{
item.Parent.Color = NodeColor.Red;
X.Color = NodeColor.Red;
item.Parent.Parent.Color = NodeColor.Black;
item = item.Parent.Parent;
}
else
{
if (item == item.Parent.Left)
{
item = item.Parent;
RightRotate(item);
}
item.Parent.Color = NodeColor.Black;
item.Parent.Parent.Color = NodeColor.Red;
LeftRotate(item.Parent.Parent);
}
}
Root.Color = NodeColor.Black;
}
}
/// <summary>
/// Добавление элемента в КЧД
/// </summary>
/// <param name="item"></param>
public void Insert(int item)
{
if (Root != null)
{
if (Search(item) != null)
{
throw new ArgumentException
("Операция невозможна - такой элемент в дереве уже существует");
}
}
RBT_Node newItem = new RBT_Node(item);
if (Root == null)
{
Root = newItem;
Root.Color = NodeColor.Black;
return;
}
RBT_Node Y = null;
RBT_Node X = Root;
while (X != null)
{
Y = X;
if (newItem.Value < X.Value)
{
X = X.Left;
}
else
{
X = X.Right;
}
}
newItem.Parent = Y;
if (Y == null)
{
Root = newItem;
}
else if (newItem.Value < Y.Value)
{
Y.Left = newItem;
}
else
{
Y.Right = newItem;
}
newItem.Left = null;
newItem.Right = null;
newItem.Color = NodeColor.Red;
InsertFixUp(newItem);
}
private RBT_Node Minimum(RBT_Node X)
{
while (X.Left /*.Left*/ != null)
{
X = X.Left;
}
if (X.Left != null)
{
if (X.Left.Right != null)
{
X = X.Left.Right;
}
}
return(X);
}
/// <summary>
/// Возвращает "младшего наследника"
/// </summary>
/// <param name="X"></param>
/// <returns></returns>
private RBT_Node TreeSuccessor(RBT_Node X)
{
if (X.Left != null)
{
return(Minimum(X));
}
else
{
RBT_Node Y = X.Parent;
while (Y != null && X == Y.Right)
{
X = Y;
Y = Y.Parent;
}
return(Y);
}
}
//public void DisplayTree()
//{
// if (Root == null)
// {
// Console.WriteLine("Nothing in the tree!");
// return;
// }
// if (Root != null)
// {
// InOrderDisplay(Root);
// }
//}
//private void InOrderDisplay(RBT_Node current)
//{
// if (current != null)
// {
// InOrderDisplay(current.left);
// Console.Write("({0}) ", current.Value);
// InOrderDisplay(current.right);
// }
//}
/// <summary>
/// Поиск элемента в дереве
/// </summary>
/// <param name="Value"></param>
public RBT_Node Search(int Value)
{
bool isFound = false;
RBT_Node temp = Root;
RBT_Node item = null;
while (!isFound)
{
if (temp == null)
{
break;
}
else if (Value < temp.Value)
{
temp = temp.Left;
}
else if (Value > temp.Value)
{
temp = temp.Right;
}
else if (Value == temp.Value)
{
isFound = true;
item = temp;
}
}
if (isFound)
{
//Console.WriteLine("{0} was found", Key);
return(temp);
}
else
{
//Console.WriteLine("{0} not found", Value);
return(null);
}
}
/// <summary>
/// Балансировка дерева после удаления элемента
/// </summary>
/// <param name="X"></param>
private void DeleteFixUp(RBT_Node X)
{
while (X != null && X != Root && X.Color == NodeColor.Black)
{
if (X == X.Parent.Left)
{
RBT_Node W = X.Parent.Right;
if (W.Color == NodeColor.Red)
{
W.Color = NodeColor.Black;
X.Parent.Color = NodeColor.Red;
LeftRotate(X.Parent);
W = X.Parent.Right;
}
if (W.Left.Color == NodeColor.Black && W.Right.Color == NodeColor.Black)
{
W.Color = NodeColor.Red;
X = X.Parent;
}
else if (W.Right.Color == NodeColor.Black)
{
W.Left.Color = NodeColor.Black;
W.Color = NodeColor.Red;
RightRotate(W);
W = X.Parent.Right;
}
W.Color = X.Parent.Color;
X.Parent.Color = NodeColor.Black;
W.Right.Color = NodeColor.Black;
LeftRotate(X.Parent);
X = Root;
}
else
{
RBT_Node W = X.Parent.Left;
if (W.Color == NodeColor.Red)
{
W.Color = NodeColor.Black;
X.Parent.Color = NodeColor.Red;
RightRotate(X.Parent);
W = X.Parent.Left;
}
if (W.Right.Color == NodeColor.Black && W.Left.Color == NodeColor.Black)
{
W.Color = NodeColor.Black;
X = X.Parent;
}
else if (W.Left.Color == NodeColor.Black)
{
W.Right.Color = NodeColor.Black;
W.Color = NodeColor.Red;
LeftRotate(W);
W = X.Parent.Left;
}
W.Color = X.Parent.Color;
X.Parent.Color = NodeColor.Black;
W.Left.Color = NodeColor.Black;
RightRotate(X.Parent);
X = Root;
}
}
if (X != null)
{
X.Color = NodeColor.Black;
}
}