public static void Traverse(AvlNode root)
{
Stack <AvlNode> treeStack = new Stack <AvlNode>();
while (true)
{
GoAlongLeftBranch(root, treeStack);
if (treeStack.Count <= 0)
{
break;
}
root = treeStack.Pop();
Console.Write(root.data + " ");
root = root.rchild;
}
}
public AvlNode(int data, AvlNode parent)
{
this.data = data;
this.parent = parent;
}
public void SetParent(AvlNode node)
{
parent = node;
}
public static void UpdateHeight(AvlNode node)
{
node.height = Math.Max(height(node.lchild), height(node.rchild)) + 1;
}
public AvlNode Insert(int data)
{
AvlNode node = Search(data);
AvlNode res = null;
//查找失败的时候才插入
if (node == null)
{
node = new AvlNode(data, _hot);
if (data < _hot.data)
{
_hot.lchild = node;
}
else
{
_hot.rchild = node;
}
_size++;
//从下往上找 一旦发现有一个祖先失衡 必将引起多个祖先失衡
bool isBalanced = true;
while (node.parent != null)
{
node = node.parent;
if (height(node.lchild) - height(node.rchild) == 2)
{
isBalanced = false;
//左左型
if (height(node.lchild) - height(node.lchild.lchild) == 1)
{
res = R_Rotate(node);
}
//左右型
else
{
res = L_R_Rotate(node);
}
}
else if (height(node.lchild) - height(node.rchild) == -2)
{
isBalanced = false;
//右右型
if (height(node.rchild) - height(node.rchild.rchild) == 1)
{
res = L_Rotate(node);
}
//右左型
else
{
res = R_L_Rotate(node);
}
}
if (!isBalanced)
{
break;
}
else
{
//平衡性虽然不变 但是高度可能改变
UpdateHeight(node);
}
}
}
if (node != null)
{
_root = node;
node = node.parent;
}
return(node);
}
//右左型 先右转 再左转
public static AvlNode R_L_Rotate(AvlNode node)
{
node.rchild = R_Rotate(node.rchild);
return(L_Rotate(node));
}
//左右型 先左转 再右转
public static AvlNode L_R_Rotate(AvlNode node)
{
node.lchild = L_Rotate(node.lchild);
return(R_Rotate(node));
}