public static RedBlackTreeNode <T> GetGrandparentNode <T>(this RedBlackTreeNode <T> node)
{
return(node.GetParentNode().GetParentNode());
}
private void InsertFixup(RedBlackTreeNode <T> node)
{
while (node.GetParentNode().Color == NodeColor.Red)
{
#region Left
if (node.GetParentNode() == node.GetGrandparentNode().Left)
{
var uncle = node.GetGrandparentNode().Right.ToRedBlackTreeNode();
#region //case 1 uncle is red then red up
if (uncle.Color == NodeColor.Red)
{
node.GetParentNode().Color = NodeColor.Black;
uncle.Color = NodeColor.Black;
node.GetGrandparentNode().Color = NodeColor.Red;
node = node.GetGrandparentNode();
}
#endregion
else
{
#region // case 2 uncle is black, node is right
if (node == node.GetParentNode().Right)
{
node = node.GetParentNode();
LeftRotate(node);
}
#endregion
#region // case 2 uncle is black, node is left。变成一条线再旋转
node.GetParentNode().Color = NodeColor.Black;
node.GetGrandparentNode().Color = NodeColor.Red;
RightRotate(node.GetGrandparentNode());
#endregion
}
}
#endregion
#region right
else
{
var uncle = node.GetGrandparentNode().Left.ToRedBlackTreeNode();
#region case 1 red up
if (uncle.Color == NodeColor.Red)
{
node.GetParentNode().Color = NodeColor.Black;
uncle.Color = NodeColor.Black;
node.GetGrandparentNode().Color = NodeColor.Red;
node = node.GetGrandparentNode();
}
#endregion
else
{
if (node == node.GetParentNode().Left)
{
node = node.GetParentNode();
RightRotate(node);
}
node.GetParentNode().Color = NodeColor.Black;
node.GetGrandparentNode().Color = NodeColor.Red;
LeftRotate(node.GetGrandparentNode());
}
}
#endregion
}
var root = Root.ToRedBlackTreeNode();
//保证性质2
root.Color = NodeColor.Black;
}
public static RedBlackTreeNode <T> GetParentNode <T>(this RedBlackTreeNode <T> node)
{
return(node.Parent as RedBlackTreeNode <T>);
}
//空节点的Parent属性不可靠，只能存储起来。
private void DeleteFixup(RedBlackTreeNode <T> node)
{
while (node != Root && node.Color == NodeColor.Black)
{
var parent = node.Parent.ToRedBlackTreeNode();
#region left
if (node == parent.Left)
{
#region case1 brother is red
var brother = parent.Right.ToRedBlackTreeNode();
if (brother.Color == NodeColor.Red)
{
brother.Color = NodeColor.Black;
parent.Color = NodeColor.Red;
LeftRotate(parent);
brother = parent.Right.ToRedBlackTreeNode();
}
#endregion
#region case2 brother child all black
if (
(
brother.Left.ToRedBlackTreeNode().Color == NodeColor.Black)
&&
(
brother.Right.ToRedBlackTreeNode().Color == NodeColor.Black))
{
brother.Color = NodeColor.Red;
node = parent;
parent = node.GetParentNode();
}
#endregion
else
{
#region case3 brother right child is black
if (
brother.Right.ToRedBlackTreeNode().Color == NodeColor.Black)
{
brother.Left.ToRedBlackTreeNode().Color = NodeColor.Black;
brother.Color = NodeColor.Red;
RightRotate(brother);
brother = parent.Right.ToRedBlackTreeNode();
}
#endregion
#region case4 brother right child is red
brother.Color = parent.Color;
parent.Color = NodeColor.Black;
brother.Right.ToRedBlackTreeNode().Color = NodeColor.Black;
LeftRotate(parent);
node = Root.ToRedBlackTreeNode();
#endregion
}
}
#endregion
#region right
else
{
#region case1 brother is red
var brother = parent.Left.ToRedBlackTreeNode();
if (brother.Color == NodeColor.Red)
{
brother.Color = NodeColor.Black;
parent.Color = NodeColor.Red;
RightRotate(parent);
brother = parent.Left.ToRedBlackTreeNode();
}
#endregion
#region case2 brother child all black
if (
(
brother.Left.ToRedBlackTreeNode().Color == NodeColor.Black) &&
(
brother.Right.ToRedBlackTreeNode().Color == NodeColor.Black))
{
brother.Color = NodeColor.Red;
node = parent;
parent = node.GetParentNode();
}
#endregion
else
{
#region case3 brother right child is black
if (brother.Left.ToRedBlackTreeNode().Color == NodeColor.Black)
{
brother.Right.ToRedBlackTreeNode().Color = NodeColor.Black;
brother.Color = NodeColor.Red;
LeftRotate(brother);
brother = parent.Left.ToRedBlackTreeNode();
}
#endregion
#region case4 brother right child is red
brother.Color = parent.Color;
parent.Color = NodeColor.Black;
brother.Left.ToRedBlackTreeNode().Color = NodeColor.Black;
RightRotate(parent);
node = Root.ToRedBlackTreeNode();
#endregion
}
}
#endregion
}
node.Color = NodeColor.Black;
}
