java二叉树的代码实现 二叉树实现 java代码

java实现二叉树层次遍历

import java.util.ArrayList;

public class TreeNode {

private TreeNode leftNode;

private TreeNode rightNode;

private String nodeName;

public TreeNode getLeftNode() {

return leftNode;

}

public void setLeftNode(TreeNode leftNode) {

this.leftNode = leftNode;

}

public TreeNode getRightNode() {

return rightNode;

}

public void setRightNode(TreeNode rightNode) {

this.rightNode = rightNode;

}

public String getNodeName() {

return nodeName;

}

public void setNodeName(String nodeName) {

this.nodeName = nodeName;

}

public static int level=0;

public static void findNodeByLevel(ArrayListTreeNode nodes){

if(nodes==null||nodes.size()==0){

return ;

}

level++;

ArrayListTreeNode temp = new ArrayList();

for(TreeNode node:nodes){

System.out.println("第"+level+"层:"+node.getNodeName());

if(node.getLeftNode()!=null){

temp.add(node.getLeftNode());

}

if(node.getRightNode()!=null){

temp.add(node.getRightNode());

}

}

nodes.removeAll(nodes);

findNodeByLevel(temp);

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

TreeNode root = new TreeNode();

root.setNodeName("root");

TreeNode node1 = new TreeNode();

node1.setNodeName("node1");

TreeNode node3 = new TreeNode();

node3.setNodeName("node3");

TreeNode node7 = new TreeNode();

node7.setNodeName("node7");

TreeNode node8 = new TreeNode();

node8.setNodeName("node8");

TreeNode node4 = new TreeNode();

node4.setNodeName("node4");

TreeNode node2 = new TreeNode();

node2.setNodeName("node2");

TreeNode node5 = new TreeNode();

node5.setNodeName("node5");

TreeNode node6 = new TreeNode();

node6.setNodeName("node6");

root.setLeftNode(node1);

node1.setLeftNode(node3);

node3.setLeftNode(node7);

node3.setRightNode(node8);

node1.setRightNode(node4);

root.setRightNode(node2);

node2.setLeftNode(node5);

node2.setRightNode(node6);

ArrayListTreeNode nodes = new ArrayListTreeNode();

nodes.add(root);

findNodeByLevel(nodes);

}

}

相关问答

Q1: java二叉树的顺序表实现

做了很多年的程序员，觉得什么树的设计并不是非常实用。二叉树有顺序存储，当一个insert大量同时顺序自增插入的时候，树就会失去平衡。树的一方为了不让塌陷，会增大树的高度。性能会非常不好。以上是题外话。分析需求在写代码。

import java.util.List;

import java.util.LinkedList;

public class Bintrees {

private int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9};

private static ListNode nodeList = null;

private static class Node {

Node leftChild;

Node rightChild;

int data;

Node(int newData) {

leftChild = null;

rightChild = null;

data = newData;

}

}

// 创建二叉树

public void createBintree() {

nodeList = new LinkedListNode();

// 将数组的值转换为node

for (int nodeIndex = 0; nodeIndex array.length; nodeIndex++) {

nodeList.add(new Node(array[nodeIndex]));

}

// 对除最后一个父节点按照父节点和孩子节点的数字关系建立二叉树

for (int parentIndex = 0; parentIndex array.length / 2 - 1; parentIndex++) {

nodeList.get(parentIndex).leftChild = nodeList.get(parentIndex * 2 + 1);

nodeList.get(parentIndex).rightChild = nodeList.get(parentIndex * 2 + 2);

}

// 最后一个父节点

int lastParentIndex = array.length / 2 - 1;

// 左孩子

nodeList.get(lastParentIndex).leftChild = nodeList.get(lastParentIndex * 2 + 1);

// 如果为奇数，建立右孩子

if (array.length % 2 == 1) {

nodeList.get(lastParentIndex).rightChild = nodeList.get(lastParentIndex * 2 + 2);

}

}

// 前序遍历

public static void preOrderTraverse(Node node) {

if (node == null) {

return;

}

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

preOrderTraverse(node.leftChild);

preOrderTraverse(node.rightChild);

}

// 中序遍历

public static void inOrderTraverse(Node node) {

if (node == null) {

return;

}

inOrderTraverse(node.leftChild);

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

inOrderTraverse(node.rightChild);

}

// 后序遍历

public static void postOrderTraverse(Node node) {

if (node == null) {

return;

}

postOrderTraverse(node.leftChild);

postOrderTraverse(node.rightChild);

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

}

public static void main(String[] args) {

Bintrees binTree = new Bintrees();

binTree.createBintree();

Node root = nodeList.get(0);

System.out.println("前序遍历：");

preOrderTraverse(root);

System.out.println();

System.out.println("中序遍历：");

inOrderTraverse(root);

System.out.println();

System.out.println("后序遍历：");

postOrderTraverse(root);

}

}

Q2: 用java怎么构造一个二叉树？

二叉树的相关操作，包括创建，中序、先序、后序（递归和非递归），其中重点的是java在先序创建二叉树和后序非递归遍历的的实现。

package com.algorithm.tree;

import java.io.File;

import java.io.FileNotFoundException;

import java.util.Queue;

import java.util.Scanner;

import java.util.Stack;

import java.util.concurrent.LinkedBlockingQueue;

public class Tree {

private Node root;

public Tree() {

}

public Tree(Node root) {

this.root = root;

}

//创建二叉树

public void buildTree() {

Scanner scn = null;

try {

scn = new Scanner(new File("input.txt"));

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

root = createTree(root,scn);

}

//先序遍历创建二叉树

private Node createTree(Node node,Scanner scn) {

String temp = scn.next();

if (temp.trim().equals("#")) {

return null;

} else {

node = new Node((T)temp);

node.setLeft(createTree(node.getLeft(), scn));

node.setRight(createTree(node.getRight(), scn));

return node;

}

}

//中序遍历(递归)

public void inOrderTraverse() {

inOrderTraverse(root);

}

public void inOrderTraverse(Node node) {

if (node != null) {

inOrderTraverse(node.getLeft());

System.out.println(node.getValue());

inOrderTraverse(node.getRight());

}

}

//中序遍历(非递归)

public void nrInOrderTraverse() {

StackNode stack = new StackNode();

Node node = root;

while (node != null || !stack.isEmpty()) {

while (node != null) {

stack.push(node);

node = node.getLeft();

}

node = stack.pop();

System.out.println(node.getValue());

node = node.getRight();

}

}

//先序遍历(递归)

public void preOrderTraverse() {

preOrderTraverse(root);

}

public void preOrderTraverse(Node node) {

if (node != null) {

System.out.println(node.getValue());

preOrderTraverse(node.getLeft());

preOrderTraverse(node.getRight());

}

}

//先序遍历（非递归）

public void nrPreOrderTraverse() {

StackNode stack = new StackNode();

Node node = root;

while (node != null || !stack.isEmpty()) {

while (node != null) {

System.out.println(node.getValue());

stack.push(node);

node = node.getLeft();

}

node = stack.pop();

node = node.getRight();

}

}

//后序遍历(递归)

public void postOrderTraverse() {

postOrderTraverse(root);

}

public void postOrderTraverse(Node node) {

if (node != null) {

postOrderTraverse(node.getLeft());

postOrderTraverse(node.getRight());

System.out.println(node.getValue());

}

}

//后续遍历(非递归)

public void nrPostOrderTraverse() {

StackNode stack = new StackNode();

Node node = root;

Node preNode = null;//表示最近一次访问的节点

while (node != null || !stack.isEmpty()) {

while (node != null) {

stack.push(node);

node = node.getLeft();

}

node = stack.peek();

if (node.getRight() == null || node.getRight() == preNode) {

System.out.println(node.getValue());

node = stack.pop();

preNode = node;

node = null;

} else {

node = node.getRight();

}

}

}

//按层次遍历

public void levelTraverse() {

levelTraverse(root);

}

public void levelTraverse(Node node) {

QueueNode queue = new LinkedBlockingQueueNode();

queue.add(node);

while (!queue.isEmpty()) {

Node temp = queue.poll();

if (temp != null) {

System.out.println(temp.getValue());

queue.add(temp.getLeft());

queue.add(temp.getRight());

}

}

}

}

//树的节点

class Node {

private Node left;

private Node right;

private T value;

public Node() {

}

public Node(Node left,Node right,T value) {

this.left = left;

this.right = right;

this.value = value;

}

public Node(T value) {

this(null,null,value);

}

public Node getLeft() {

return left;

}

public void setLeft(Node left) {

this.left = left;

}

public Node getRight() {

return right;

}

public void setRight(Node right) {

this.right = right;

}

public T getValue() {

return value;

}

public void setValue(T value) {

this.value = value;

}

}

测试代码：

package com.algorithm.tree;

public class TreeTest {

/**

* @param args

*/

public static void main(String[] args) {

Tree tree = new Tree();

tree.buildTree();

System.out.println("中序遍历");

tree.inOrderTraverse();

tree.nrInOrderTraverse();

System.out.println("后续遍历");

//tree.nrPostOrderTraverse();

tree.postOrderTraverse();

tree.nrPostOrderTraverse();

System.out.println("先序遍历");

tree.preOrderTraverse();

tree.nrPreOrderTraverse();

//

}

}

Q3: java构建二叉树算法

//******************************************************************************************************//

//*****本程序包括简单的二叉树类的实现和前序,中序,后序,层次遍历二叉树算法,*******//

//******以及确定二叉树的高度,制定对象在树中的所处层次以及将树中的左右***********//

//******孩子节点对换位置,返回叶子节点个数删除叶子节点,并输出所删除的叶子节点**//

//*******************************CopyRight By phoenix*******************************************//

//************************************Jan 12,2008*************************************************//

//****************************************************************************************************//

public class BinTree {

public final static int MAX=40;

private Object data; //数据元数

private BinTree left,right; //指向左,右孩子结点的链

BinTree []elements = new BinTree[MAX];//层次遍历时保存各个节点

int front;//层次遍历时队首

int rear;//层次遍历时队尾

public BinTree()

{

}

public BinTree(Object data)

{ //构造有值结点

this.data = data;

left = right = null;

}

public BinTree(Object data,BinTree left,BinTree right)

{ //构造有值结点

this.data = data;

this.left = left;

this.right = right;

}

public String toString()

{

return data.toString();

}//前序遍历二叉树

public static void preOrder(BinTree parent){

if(parent == null)

return;

System.out.print(parent.data+" ");

preOrder(parent.left);

preOrder(parent.right);

}//中序遍历二叉树

public void inOrder(BinTree parent){

if(parent == null)

return;

inOrder(parent.left);

System.out.print(parent.data+" ");

inOrder(parent.right);

}//后序遍历二叉树

public void postOrder(BinTree parent){

if(parent == null)

return;

postOrder(parent.left);

postOrder(parent.right);

System.out.print(parent.data+" ");

}// 层次遍历二叉树

public void LayerOrder(BinTree parent)

{

elements[0]=parent;

front=0;rear=1;

while(frontrear)

{

try

{

if(elements[front].data!=null)

{

System.out.print(elements[front].data + " ");

if(elements[front].left!=null)

elements[rear++]=elements[front].left;

if(elements[front].right!=null)

elements[rear++]=elements[front].right;

front++;

}

}catch(Exception e){break;}

}

}//返回树的叶节点个数

public int leaves()

{

if(this == null)

return 0;

if(left == nullright == null)

return 1;

return (left == null ? 0 : left.leaves())+(right == null ? 0 : right.leaves());

}//结果返回树的高度

public int height()

{

int heightOfTree;

if(this == null)

return -1;

int leftHeight = (left == null ? 0 : left.height());

int rightHeight = (right == null ? 0 : right.height());

heightOfTree = leftHeightrightHeight?rightHeight:leftHeight;

return 1 + heightOfTree;

}

//如果对象不在树中,结果返回-1;否则结果返回该对象在树中所处的层次,规定根节点为第一层

public int level(Object object)

{

int levelInTree;

if(this == null)

return -1;

if(object == data)

return 1;//规定根节点为第一层

int leftLevel = (left == null?-1:left.level(object));

int rightLevel = (right == null?-1:right.level(object));

if(leftLevel0rightLevel0)

return -1;

levelInTree = leftLevelrightLevel?rightLevel:leftLevel;

return 1+levelInTree;

}

//将树中的每个节点的孩子对换位置

public void reflect()

{

if(this == null)

return;

if(left != null)

left.reflect();

if(right != null)

right.reflect();

BinTree temp = left;

left = right;

right = temp;

}// 将树中的所有节点移走,并输出移走的节点

public void defoliate()

{

String innerNode = "";

if(this == null)

return;

//若本节点是叶节点，则将其移走

if(left==nullright == null)

{

System.out.print(this + " ");

data = null;

return;

}

//移走左子树若其存在

if(left!=null){

left.defoliate();

left = null;

}

//移走本节点，放在中间表示中跟移走...

innerNode += this + " ";

data = null;

//移走右子树若其存在

if(right!=null){

right.defoliate();

right = null;

}

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

BinTree e = new BinTree("E");

BinTree g = new BinTree("G");

BinTree h = new BinTree("H");

BinTree i = new BinTree("I");

BinTree d = new BinTree("D",null,g);

BinTree f = new BinTree("F",h,i);

BinTree b = new BinTree("B",d,e);

BinTree c = new BinTree("C",f,null);

BinTree tree = new BinTree("A",b,c);

System.out.println("前序遍历二叉树结果: ");

tree.preOrder(tree);

System.out.println();

System.out.println("中序遍历二叉树结果: ");

tree.inOrder(tree);

System.out.println();

System.out.println("后序遍历二叉树结果: ");

tree.postOrder(tree);

System.out.println();

System.out.println("层次遍历二叉树结果: ");

tree.LayerOrder(tree);

System.out.println();

System.out.println("F所在的层次: "+tree.level("F"));

System.out.println("这棵二叉树的高度: "+tree.height());

System.out.println("--------------------------------------");

tree.reflect();

System.out.println("交换每个节点的孩子节点后......");

System.out.println("前序遍历二叉树结果: ");

tree.preOrder(tree);

System.out.println();

System.out.println("中序遍历二叉树结果: ");

tree.inOrder(tree);

System.out.println();

System.out.println("后序遍历二叉树结果: ");

tree.postOrder(tree);

System.out.println();

System.out.println("层次遍历二叉树结果: ");

tree.LayerOrder(tree);

System.out.println();

System.out.println("F所在的层次: "+tree.level("F"));

System.out.println("这棵二叉树的高度: "+tree.height());

}

Q4: 用java怎么构造一个二叉树呢？

java构造二叉树，可以通过链表来构造，如下代码：

public class BinTree {

public final static int MAX=40;

BinTree []elements = new BinTree[MAX];//层次遍历时保存各个节点

    int front;//层次遍历时队首

    int rear;//层次遍历时队尾

private Object data; //数据元数

private BinTree left,right; //指向左,右孩子结点的链

public BinTree()

{

}

public BinTree(Object data)

{ //构造有值结点

   this.data = data;

   left = right = null;

}

public BinTree(Object data,BinTree left,BinTree right)

{ //构造有值结点

   this.data = data;

   this.left = left;

   this.right = right;

}

public String toString()

{

   return data.toString();

}

//前序遍历二叉树

public static void preOrder(BinTree parent){ 

     if(parent == null)

      return;

     System.out.print(parent.data+" ");

     preOrder(parent.left);

     preOrder(parent.right);

}

//中序遍历二叉树

public void inOrder(BinTree parent){

   if(parent == null)

      return;

   inOrder(parent.left);

   System.out.print(parent.data+" ");

     inOrder(parent.right);

}

//后序遍历二叉树

public void postOrder(BinTree parent){

   if(parent == null)

    return;

   postOrder(parent.left);

   postOrder(parent.right);

   System.out.print(parent.data+" ");

}

// 层次遍历二叉树 

public void LayerOrder(BinTree parent)

{ 

     elements[0]=parent;

     front=0;rear=1;

   while(frontrear)

   {

    try

    {

        if(elements[front].data!=null)

        {

           System.out.print(elements[front].data + " ");

           if(elements[front].left!=null)

          elements[rear++]=elements[front].left;

           if(elements[front].right!=null)

          elements[rear++]=elements[front].right;

           front++;

        }

    }catch(Exception e){break;}

   }

}

//返回树的叶节点个数

public int leaves()

{

   if(this == null)

    return 0;

   if(left == nullright == null)

    return 1;

   return (left == null ? 0 : left.leaves())+(right == null ? 0 : right.leaves());

}

//结果返回树的高度

public int height()

{

   int heightOfTree;

   if(this == null)

    return -1;

   int leftHeight = (left == null ? 0 : left.height());

   int rightHeight = (right == null ? 0 : right.height());

   heightOfTree = leftHeightrightHeight?rightHeight:leftHeight;

   return 1 + heightOfTree;

}

//如果对象不在树中,结果返回-1;否则结果返回该对象在树中所处的层次,规定根节点为第一层

public int level(Object object)

{

   int levelInTree;

   if(this == null)

    return -1;

   if(object == data)

    return 1;//规定根节点为第一层

   int leftLevel = (left == null?-1:left.level(object));

   int rightLevel = (right == null?-1:right.level(object));

   if(leftLevel0rightLevel0)

    return -1;

   levelInTree = leftLevelrightLevel?rightLevel:leftLevel;

   return 1+levelInTree;

  

}

//将树中的每个节点的孩子对换位置

public void reflect()

{

   if(this == null)

    return;

   if(left != null)

    left.reflect();

   if(right != null)

    right.reflect();

   BinTree temp = left;

   left = right;

   right = temp;

}

// 将树中的所有节点移走,并输出移走的节点

public void defoliate()

{

   if(this == null)

    return;

   //若本节点是叶节点，则将其移走

   if(left==nullright == null)

   {

    System.out.print(this + " ");

    data = null;

    return;

   }

   //移走左子树若其存在

   if(left!=null){

    left.defoliate();

    left = null;

   }

   //移走本节点，放在中间表示中跟移走...

   String innerNode += this + " ";

   data = null;

   //移走右子树若其存在

   if(right!=null){

    right.defoliate();

    right = null;

   }

}

   /**

* @param args

*/

public static void main(String[] args) {

   // TODO Auto-generated method stub

   BinTree e = new BinTree("E");

   BinTree g = new BinTree("G");

   BinTree h = new BinTree("H");

   BinTree i = new BinTree("I");

   BinTree d = new BinTree("D",null,g);

  

   BinTree f = new BinTree("F",h,i);

   BinTree b = new BinTree("B",d,e);

   BinTree c = new BinTree("C",f,null);

   BinTree tree = new BinTree("A",b,c);

  

        System.out.println("前序遍历二叉树结果: ");

        tree.preOrder(tree);

        System.out.println();

        System.out.println("中序遍历二叉树结果: ");

        tree.inOrder(tree);

        System.out.println();

        System.out.println("后序遍历二叉树结果: ");

        tree.postOrder(tree);

        System.out.println();

      System.out.println("层次遍历二叉树结果: ");

     tree.LayerOrder(tree);

     System.out.println();

        System.out.println("F所在的层次: "+tree.level("F"));

        System.out.println("这棵二叉树的高度: "+tree.height());

         System.out.println("--------------------------------------");

         tree.reflect();

          System.out.println("交换每个节点的孩子节点后......");

          System.out.println("前序遍历二叉树结果: ");

        tree.preOrder(tree);

        System.out.println();

        System.out.println("中序遍历二叉树结果: ");

        tree.inOrder(tree);

        System.out.println();

        System.out.println("后序遍历二叉树结果: ");

        tree.postOrder(tree);

        System.out.println();

      System.out.println("层次遍历二叉树结果: ");

     tree.LayerOrder(tree);

     System.out.println();

        System.out.println("F所在的层次: "+tree.level("F"));

        System.out.println("这棵二叉树的高度: "+tree.height());

}

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