/**
 * 二叉树的链表节点类
 * @author qiangzi
 * @param <T>
 */
public class BinaryNode<T> {

 public T data; //数据域
 public BinaryNode<T> left,right; //链域，分别只向左右孩子
 public BinaryNode(T data, BinaryNode<T> left, BinaryNode<T> right) {
  this.data = data;
  this.left = left;
  this.right = right;
 }
 
 public BinaryNode(T data){
  this(data, null, null);
 }
 public BinaryNode(){
  this(null,null,null);
 }
}

package com.hzq.test;

public class BinaryTree<T>{
 public BinaryNode<T> root; // 根节点，节点结构为二叉链表
 public BinaryTree(){
  this.root = null;//构造空二叉树
 }
 public boolean isEmpty(){
  return this.root == null;
 }
 
 //先跟次序遍历二叉树
 public void preOrder(){
  System.out.println(“先根次序遍历二叉树”);
  preOrder(root);
  System.out.println();
 }

 public void preOrder(BinaryNode<T> p) {
  if (p != null) {
   System.out.print(p.data.toString() + ” “); // 访问当前节点
   preOrder(p.left); // 按先根次序遍历当前节点的左子树，递归调用
   preOrder(p.right);// 按先根次序遍历当前节点的右子树，递归调用
  }
 }
 
 //中根次序遍历二叉树
 public void inOrder(){
  System.out.println(“中根次序遍历二叉树”);
  inOrder(root);
  System.out.println();
 }
 public void inOrder(BinaryNode<T> p){
  if(p!=null){
   inOrder(p.left);
   System.out.print(p.data.toString()+” “);
   inOrder(p.right);
  }
 }
 
 //后根次序遍历二叉树
 public void postOrder(){
  System.out.println(“后根次序遍历二叉树”);
  postOrder(root);
  System.out.println();
 }
 public void postOrder(BinaryNode<T> p) {
  if(p!=null){
   postOrder(p.left);
   postOrder(p.right);
   System.out.print(p.data.toString()+” “);
  }
 }
 
 //求节点个数
 public int count(){
  return count(root);
 }
 private int count(BinaryNode<T> p) {
  if(p==null){
   return 0;
  }
  return 1+count(p.left)+count(p.right);
 }
 
 //求高度
 public int height(){
  return height(root);
 }
 private int height(BinaryNode<T> p) {
  if(p== null){
   return 0;
  }
  int lh = height(p.left);
  int rh = height(p.right);
  return (lh>=rh)?lh+1:rh+1;
 }
 
 //查找
 public BinaryNode<T> search(T key){
  return this.search(root,key);
 }
 private BinaryNode<T> search(BinaryNode<T> p, T key) {
  if(p == null || key == null){
   return null;
  }
  if(p.data.equals(key)){
   return p;
  }
  BinaryNode<T> find = search(p.left, key);
  if(find == null){
   find = search(p.right,key);
  }
  return find;
 }
 
 //获取父节点
 public BinaryNode<T> getParent(BinaryNode<T> node){
  if(root == null || node == null || root == node){
   return null;
  }
  return getParent(root,node);
 }
 private BinaryNode<T> getParent(BinaryNode<T> p, BinaryNode<T> node) {
  if(p == null){
   return null;
  }
  if(p.left == node || p.right == node){
   return p;
  }
  BinaryNode<T> find = getParent(p.left,node);
  if(find == null){
   find = getParent(p.right,node);
  }
  return find;
 }
 
 //二叉树的插入与删除
 //插入
 public void insertBinary(T x){
  root = new BinaryNode<T>(x,root,null);
 }
 //插入元素X作为p节点的孩子，若leftChild为true，插入节点为左孩子，否则为右孩子
 public BinaryNode<T> insertBinary(BinaryNode<T> p,T x,boolean leftChild){
  if(p == null || x == null){
   return null;
  }
  if(leftChild){
   p.left = new BinaryNode<T>(x,p.left,null);
   return p.left;
  }
  p.right = new BinaryNode<T>(x,null,p.right);
  return p.right;
 }
 
 //删除
 public void removeAll(){
  this.root = null;
 }
 
 public void removeChild(BinaryNode<T> p,boolean leftChild){
  if(p!=null){
   if(leftChild){
    p.left = null;
   }else{
    p.right = null;
   }
  }
 }
 
}

package com.hzq.test;

public class BinaryTreeClient {
 public static void main(String[] args) {
  BinaryTree<String> bitree = make();
  bitree.preOrder();
  bitree.inOrder();
  bitree.postOrder();
  System.out.println(bitree.count());
  System.out.println(bitree.height());
  System.out.println(bitree.search(“E”));
 }
 /**
  * 构造一颗二叉树
  * @return
  */
 public static BinaryTree<String> make(){
  BinaryTree<String> bitree = new BinaryTree<String>();
  BinaryNode<String> child_f,child_d,child_b,child_c;
  child_d = new BinaryNode<String>(“D”,null,new BinaryNode<String>(“G”));
  child_b = new BinaryNode<String>(“B”,child_d,null);
  child_f = new BinaryNode<String>(“F”,new BinaryNode<String>(“H”),null);
  child_c = new BinaryNode<String>(“C”,new BinaryNode<String>(“E”),child_f);
  bitree.root = new BinaryNode<String>(“A”,child_b,child_c);
  return bitree;
 }
}