Question

我正在创建AVL二叉树，其唯一的问题是根不会改变其位置或获得平衡，除了所有其他孩子的根或叶等

非常感谢任何帮助！

逻辑层文件

 public class Node
    {
        public int data;
        public Node left, right;

        public Node(int data)
        {
            this.data = data;
            left = null;
            right = null;
        }
    }

 public class BinaryTree
    {
        public Node root;
        public BinaryTree()
        {
            root = null;
        }
        public int height(Node temp)
        {
            int h = 0;
            if (temp != null)
            {
                int l_height = height(temp.left);
                int r_height = height(temp.right);
                int max_height = Math.Max(l_height, r_height);
                h = max_height + 1;
            }
            return h;
        }
        public int diff(Node temp)
        {
            int l_height = height(temp.left);
            int r_height = height(temp.right);
            int b_factor = l_height - r_height;
            return b_factor;
        }

        Node rr_rotation(Node parent)
        {
            Node temp;
            temp = parent.right;
            parent.right = temp.left;
            temp.left = parent;
            return temp;
        }
        Node ll_rotation(Node parent)
        {
            Node temp;
            temp = parent.left;
            parent.left = temp.right;
            temp.right = parent;
            return temp;
        }
        Node lr_rotation(Node parent)
        {
            Node temp;
            temp = parent.left;
            parent.left = rr_rotation(temp);
            return ll_rotation(parent);
        }
        Node rl_rotation(Node parent)
        {
            Node temp;
            temp = parent.right;
            parent.right = ll_rotation(temp);
            return rr_rotation(parent);
        }
        Node balance(Node temp)
        {
            int bal_factor = diff(temp);
            if (bal_factor > 1)
            {
                if (diff(temp.left) > 0)
                    temp = ll_rotation(temp);
                else
                    temp = lr_rotation(temp);
            }
            else if (bal_factor < -1)
            {
                if (diff(temp.right) > 0)
                    temp = rl_rotation(temp);
                else
                    temp = rr_rotation(temp);
            }
            return temp;
        }

        public Node addNode(int data)  //  It only add the Root(that is 55 in the fig)
        {
            Node newNode = new Node(data);
            if (root == null)
            {
                root = newNode;

            }
            return root;
        }
        public Node insertNode(Node root, int newNode)  //But I want to make this should add root node.
        {

            if (root == null)            (I think here is some problem)
            {
                root = new Node(newNode);
                root.data = newNode;
                root.left = null;
                root.right = null;
                return root;
            }


            if (newNode < root.data)
            {
                root.left = insertNode(root.left, newNode);
                root = balance(root);
            }
            else if (newNode >= root.data)
            {
                root.right = insertNode(root.right, newNode);
                root = balance(root);
            }
            return root;
        }
    }

展示图层文件

 public partial class PresentationLayer : Form
    {
        BinaryTree obj = new BinaryTree();
        int a, b;

        public PresentationLayer()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)  //add node button
        {
            int num = 0;
            bool result = int.TryParse(textBox1.Text, out num);

            if (result)
            {
                a = Int32.Parse(textBox1.Text);
                obj.addNode(a);    //It creates root
               textBox1.Hide();
               button1.Hide();
            }
        }
           private void button2_Click_1(object sender, EventArgs e)   //insert button
        {
            int num = 0;
            bool result = int.TryParse(textBox2.Text, out num);

            if (result)
            {
                b = Int32.Parse(textBox2.Text);
                Node abc = new Node(b);
                obj.insertNode(obj.root, b);   //It is not creating root
                textBox2.Clear();
            }
        }
    }
}

非常感谢任何帮助！

Answer 1

您应该将案例添加到ll_rotation和rr_rotation函数中以处理根旋转的时间。您应该能够检查参数parent是否与root是同一个节点，如果是，请设置root以引用新的旋转节点。

例如，每Wikipedia's example of left rotation：

向左旋转变为：

如果调用ll_rotation(P)，P与root属于同一节点，则该函数应将Q指定为新root

仅在主根中平衡AVL树

1 个答案: