/**

* 二叉树优点：1.有序数组；2.链表。

* 数值大的在放右边，小的放左边

*

*/

public class TreeList {

public static void main(String[] args){

TreeList tl = new TreeList();

tl.insertNode(1);

tl.insertNode(21);

tl.insertNode(23);

tl.insertNode(14);

tl.insertNode(5);

tl.insertNode(46);

tl.insertNode(27);

tl.insertNode(18);

tl.insertNode(79);

tl.insertNode(10);

tl.inorderTraversal();

}

TreeNode root;

//插入结点

public synchronized void insertNode(int insertValue){

if(root == null){

root = new TreeNode(insertValue);

} else{

root.insert(insertValue);

}

}

//前序遍历

public synchronized void preorderTraversal(){

preorderHepler(root);

}

private void preorderHepler(TreeNode node){

if(node==null){

return;

}

System.out.println(node.data+" ");

preorderHepler(node.leftNode);

preorderHepler(node.rightNode);

}

//中序遍历 值从小到大显示

public synchronized void inorderTraversal(){

inorderHepler(root);

}

private void inorderHepler(TreeNode node){

if(node==null){

return;

}

inorderHepler(node.leftNode);

System.out.println(node.data+" ");

inorderHepler(node.rightNode);

}

}

class TreeNode{

TreeNode leftNode;

TreeNode rightNode;

int data;

public TreeNode(){

super();

}

public TreeNode(int nodeData){

this.data = nodeData;

this.leftNode = this.rightNode = null;

}

public synchronized void insert(int insertValue){

if(insertValue<data){

if(leftNode==null){

leftNode = new TreeNode(insertValue);

}else{

leftNode.insert(insertValue);

}

} else if (insertValue>data){

if(rightNode==null){

rightNode = new TreeNode(insertValue);

}else{

rightNode.insert(insertValue);

}

}

}

}