/// <summary>
/// 左旋一次，再右旋一次
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
public AVLTreeNode turnLeftRight(AVLTreeNode node)
{
node.left = turnLeft(node.left);
return(turnRight(node));
}
/// <summary>
/// 删除
/// </summary>
/// <param name="root"></param>
/// <param name="data"></param>
/// <returns></returns>
public AVLTreeNode delete(AVLTreeNode root, int data)
{
if (root == null)
{
return(null);
}
if (data < root.data)
{
root.left = delete(root.left, data);
if (getHeight(root.left) - getHeight(root.right) == 2)
{
if (data < root.left.data)
{
Console.WriteLine("left=" + data);
root = turnRight(root);
}
else
{
root = turnLeftRight(root);
}
}
}
else if (data > root.data)
{
root.right = delete(root.right, data);
if (getHeight(root.right) - getHeight(root.left) == 2)
{
if (data > root.right.data)
{
root = turnLeft(root);
}
else
{
root = turnRightLeft(root);
}
}
}
else if (data == root.data)//等于
{
if (root.left != null && root.right != null)
{
//寻找后继者，为右子树中最小的点
root.data = getSon(root.right).data;
//删除那个后继者
root.right = delete(root.right, root.data);
}
else
{
if (root.left != null)
{
root = root.left;
}
else if (root.right != null)
{
root = root.right;
}
else
{
return(null);
}
}
}
//更新高度
root.height = getMaxHeight(root.left, root.right);
return(root);
}
/// <summary>
/// 先右旋一次在左旋一次
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
public AVLTreeNode turnRightLeft(AVLTreeNode node)
{
node.right = turnRight(node.right);
return(turnLeft(node));
}