把二元查找树转变成排序的双向链表

 题目：
输入一棵二元查找树，将该二元查找树转换成一个排序的双向链表。
要求不能创建任何新的结点，只调整指针的指向。
   
  10
  / /
 6 14
 / / / /
4 8 12 16
   
 转换成双向链表
4=6=8=10=12=14=16。

package com.itcast.demo.random;

import java.util.Arrays;
import java.util.Scanner;

public class TreeNodeDemo {
private Node root;

private class Node {
private Node left;
private Node right;
private int data;

public Node(int data) {
this.left = null;
this.right = null;
this.data = data;
}
}
public TreeNodeDemo() {
root = null;
}
public void buildTree(Node node, int data) {
if (root == null) {
root = new Node(data);
} else {
if (data < node.data) {
if (node.left == null) {
node.left = new Node(data);
} else {
buildTree(node.left, data);
}
} else {
if (node.right == null) {
node.right = new Node(data);
} else {
buildTree(node.right, data);
}
}
}
}
private Node last = null;;

public void ConvertNode(Node node) {

if (node == null)
return;

if (node.left != null)
ConvertNode(node.left);
node.left = last;

if (last != null)
last.right = node;
last = node;
if (node.right != null)
ConvertNode(node.right);

}

public void print(Node node) {

Node r = node;
while (r != null) {
System.out.print(r.data );
if(r.right !=null){
System.out.print("=");
}
r = r.right;
}
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("请随意输入一串数字：");
Scanner sc = new Scanner(System.in);
String[] num = null;
num = sc.nextLine().split(" ");
int[] number = new int[num.length];
for (int i = 0; i < number.length; i++) {
number[i] = Integer.valueOf(num[i]);
}

Arrays.sort(number);
TreeNodeDemo tn = new TreeNodeDemo();
for (int i = 0; i < number.length; i++) {
tn.buildTree(tn.root, number[i]);
}
tn.ConvertNode(tn.root);
tn.print(tn.root);
}

}