Java数据结构--- 二叉树（二叉排序树，层次遍历二叉树节点）

Java 二叉树数据结构

今天就写一下二叉树的常用操作，明天准备写一些图中的常用函数！以后每天都要更新博客，从此要养成，积累的好习惯。俗话说，滴水穿石，对于以前自己没有写博客的习惯，感觉很可惜，做过很多工作，但就是因为没有及时记下来，所以干什么忘什么，基本很多工作干完了一段时间也就忘了，感觉很可惜。既然决定了写博客，那以后每天多少都要写点，也作为自己一天工作的总结。

本文包括二叉树的常用函数，包括二叉排序树的建立，层次遍历二叉树节点，找最大，最小节点，先序，中序，后序遍历等常用操作！

<pre name="code" class="java">package com.robin.binaryTree;public class Node {public int data;public Node left;public Node right;public Node(int data){this.data = data;this.left = null;this.right = null;}}

</pre><pre code_snippet_id="627062" snippet_file_name="blog_20150324_3_1929932" name="code" class="java" style="text-align: left;"><pre name="code" class="java">package com.robin.binaryTree;import java.util.LinkedList;import java.util.Queue;public class BinaryTree {public Node root;//构造函数public BinaryTree(){this.root = null;}public void buildTree(int[] data){for(int i = 0; i < data.length; i++){insertNode(data[i]);}}public void insertNode(int data){Node newNode = new Node(data);if(this.root == null){root = new Node(data);}else{Node current = root;Node parent;while(true){parent = current;if(data < current.data){current = current.left;if(current == null){parent.left = newNode;return;}}else{current = current.right;if(current == null){parent.right = newNode;return;}}}}}public void preOrder(){this.preOrder(this.root);}public void preOrder(Node localRoot){if(localRoot != null){System.out.print(localRoot.data + " ");this.preOrder(localRoot.left);this.preOrder(localRoot.right);}}public void inOrder(){this.inOrder(this.root);}public void inOrder(Node localRoot){if(localRoot != null){this.inOrder(localRoot.left);System.out.print(localRoot.data + " ");this.inOrder(localRoot.right);}}public void postOrder(){this.postOrder(this.root);}public void postOrder(Node localRoot){if(localRoot != null){this.postOrder(localRoot.left);this.postOrder(localRoot.right);System.out.print(localRoot.data + " ");}}public void layoutOrder(){this.layoutOrder(this.root);}public void layoutOrder(Node localRoot){if(localRoot == null){return;}Queue<Node> queue = new LinkedList<Node>();queue.add(localRoot);while(!queue.isEmpty()){Node node = queue.poll();System.out.print(node.data +" ");if(node.left != null)queue.add(node.left);if(node.right != null)queue.add(node.right);}System.out.println();}public void findMin(){this.findMin(this.root);}public void findMin(Node node){Node current = node;if(node == null){return;}while(current.left != null){current = current.left;}System.out.println("the min data is:"+current.data);}public void findMax(){this.findMax(this.root);}public void findMax(Node node){Node current = node;if(node == null){return;}while(current.right != null){current = current.right;}System.out.println("the max data is:"+current.data);}public static void main(String[] args) {BinaryTree bt = new BinaryTree();int[] data = {2,8,7,4,9,3,1,6,7,5};bt.buildTree(data);bt.preOrder();System.out.println();bt.inOrder();System.out.println();bt.postOrder();System.out.println();bt.layoutOrder();bt.findMin();bt.findMax();}}