二叉搜索树

package 第四章2;

import java.util.LinkedList;
import java.util.Queue;

import javax.xml.bind.Unmarshaller;

public class BinarySearchTree2<T extends Comparable<? super T>>
{
    Node<T> root;
    public BinarySearchTree2() {
        root=null;
    }
    public static class Node<T>
    {
        T data;
        Node<T> left;
        Node<T> right;

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

        public Node(T data,Node<T> left,Node<T> right)
        {this.data=data;this.left=left;this.right=right;}
    }
    public void insert(T x)
    {
        root=insert(x,root);
    }
    private Node<T> insert(T x, Node<T> root) 
    {
        if(root==null)
            return new Node<T>(x,null, null);
        int compareResult=x.compareTo(root.data);
        if(compareResult<0)
            root.left=insert(x, root.left);
        else if(compareResult>0)
            root.right=insert(x, root.right);
        else 
            ;
        return root;
    }
    public void remove(T x)
    {
        root=remove(x, root);
    }
    private Node<T> remove(T x,Node<T> root)
    {
        if(root==null)
            ;// do nothing ,not found
        int compareResult=x.compareTo(root.data);

        if(compareResult<0)
            root.left=remove(x, root.left);
        else if(compareResult>0)
            root.right=remove(x, root.right);
        else if(root.left!=null && root.right!=null)
        {
            T element=findMin(root.right);
            root.data=element;
            root.right=remove(element, root.right);
        }
        else 
            root=root.left!=null?root.left:root.right;
         return root;
    }
    public T findMin()
    {
        return findMin(root);
    }
    public T findMin(Node<T> root)
    {
        Node<T> p=root;
        if (p==null) {
            throw new RuntimeException("当前二叉树为空树");
        }
        while(p.left!=null)
        {
            p=p.left;
        }
        return p.data;
    }
    public T findMax()
    {
        Node<T> p=root;
        if (p==null) {
            throw new RuntimeException("当前二叉树为空树");
        }
        while(p.right!=null)
        {
            p=p.right;
        }
        return p.data;
    }


    public void layerview()
    {
        LinkedList<Node<T>> queue=new LinkedList<>();
        queue.addLast(root);
        Node<T> p;
        while(!queue.isEmpty())
        {
            p=queue.removeFirst();
            System.out.print(p.data+" ");
            if(p.left!=null)
                queue.addLast(p.left);
            if(p.right!=null)
                queue.addLast(p.right); 
        }System.out.println();
    }
    public static void main(String[] args) {
        BinarySearchTree2<Integer> tree=new BinarySearchTree2<Integer>();
        tree.insert(3);
        tree.insert(13);
        tree.insert(43);
        tree.insert(21);
        tree.insert(99);
        tree.insert(65);
        tree.insert(24);
        tree.insert(45);
        tree.insert(77);
        tree.layerview();
        System.out.println(tree.findMin()); 
        System.out.println(tree.findMax());
        tree.remove(99);
        tree.layerview();
        tree.remove(21);
        tree.layerview();
    }
}