protected override RedBlackNode <TK, TV> Delete(RedBlackNode <TK, TV> node, TK key)
{
if (key.CompareTo(node.Key) < 0)
{
if (!IsRed(node.left) && !IsRed(node.left.left))
{
node = MoveRedLeft(node);
}
node.left = Delete(node.left, key);
}
else
{
if (IsRed(node.left))
{
node = RotateRight(node);
}
if (key.CompareTo(node.Key) == 0 && node.right == null)
{
return(null);
}
if (!IsRed(node.right) && !IsRed(node.right.right))
{
node = MoveRedRight(node);
}
if (key.CompareTo(node.Key) == 0)
{
RedBlackNode <TK, TV> temp = node;
node = GetMin(temp.right);
node.color = temp.color;
node.left = temp.left;
node.right = DeleteMin(temp.right);
node.size = SizeOfNode(node.left) + SizeOfNode(node.right) + 1;
}
else
{
node.right = Delete(node.right, key);
}
}
return(Balance(node));
}
protected virtual RedBlackNode <TK, TV> Balance(RedBlackNode <TK, TV> node)
{
if (IsRed(node.right) && !IsRed(node.left))
{
node = RotateLeft(node);
}
if (IsRed(node.left) && IsRed(node.left.left))
{
node = RotateRight(node);
}
if (IsRed(node.left) && IsRed(node.right))
{
FlipColors(node);
}
node.size = SizeOfNode(node.left) + SizeOfNode(node.right) + 1;
return(node);
}
protected override RedBlackNode <TK, TV> DeleteMax(RedBlackNode <TK, TV> node)
{
if (IsRed(node.left))
{
node = RotateRight(node);
}
if (node.right == null)
{
return(null);
}
if (!IsRed(node.right) && !IsRed(node.right.left))
{
node = MoveRedRight(node);
}
node.right = DeleteMax(node.right);
return(Balance(node));
}
/*******************************************************************
* 辅助函数
*******************************************************************/
protected override RedBlackNode <TK, TV> Put(RedBlackNode <TK, TV> node, TK key, TV value,
Func <RedBlackNode <TK, TV> > create)
{
if (node == null)
{
return(create());
}
int cmp = key.CompareTo(node.Key);
if (cmp < 0)
{
node.left = Put(node.left, key, value, create);
}
else if (cmp > 0)
{
node.right = Put(node.right, key, value, create);
}
else
{
node.Value = value;
}
if (IsRed(node.right) && !IsRed(node.left))
{
node = RotateLeft(node);
}
if (IsRed(node.left) && IsRed(node.left.left))
{
node = RotateRight(node);
}
if (IsRed(node.left) && IsRed(node.right))
{
FlipColors(node);
}
node.size = SizeOfNode(node.left) + SizeOfNode(node.right) + 1;
return(node);
}
public RedBlackNode(TKey key, TValue value, Color color, int size = 1, RedBlackNode <TKey, TValue> left = null,
RedBlackNode <TKey, TValue> right = null) : base(key, value, size, left, right)
{
this.color = color;
}
/// <summary>
/// 当一个节点的左右两条链接都是红色链接时，需要转换颜色，
/// 把当前节点转换成红色，两个直接点转换成黑色
/// </summary>
/// <param name="node">要转换的节点</param>
protected virtual void FlipColors(RedBlackNode <TK, TV> node)
{
node.color = RedBlackNode <TK, TV> .Color.Red;
node.left.color = RedBlackNode <TK, TV> .Color.Black;
node.right.color = RedBlackNode <TK, TV> .Color.Black;
}
/// <summary>
/// 判断连接到当前节点的链接是否为红色
/// </summary>
/// <param name="node">要判断的节点</param>
protected virtual bool IsRed(RedBlackNode <TK, TV> node)
{
return(node != null && node.color == RedBlackNode <TK, TV> .Color.Red);
}
