本文目录一览：
写一个java层次遍历二叉树,简单点就可以,我要的是代码,不是纯文字说明
public class BinaryNode {
Object element;
BinaryNode left;
BinaryNode right;
}
import java.util.*;
public class Queue {
protected LinkedList list;
// Postcondition: this Queue object has been initialized.
public Queue() {
list = new LinkedList();
} // default constructor
// Postcondition: the number of elements in this Queue object has been
// returned.
public int size() {
return list.size();
} // method size
// Postcondition: true has been returned if this Queue object has no
// elements. Otherwise, false has been returned.
public boolean isEmpty() {
return list.isEmpty();
} // method isEmpty
// Postconditon: A copy of element has been inserted at the back of this
// Queue object. The averageTime (n) is constant and
// worstTime (n) is O (n).
public void enqueue(Object element) {
list.addLast(element);
} // method enqueue
// Precondition: this Queue object is not empty. Otherwise,
// NoSuchElementException will be thrown.
// Postcondition: The element that was at the front of this Queue object -
// just before this method was called -- has been removed
// from this Queue object and returned.
public Object dequeue() {
return list.removeFirst();
} // method dequeue
// Precondition: this Queue object is not empty. Otherwise,
// NoSuchElementException will be thrown.
// Postcondition: the element at index 0 in this Queue object has been
// returned.
public Object front() {
return list.getFirst();
} // method front
} // Queue class
import java.io.IOException;
public class BinaryTree {
BinaryNode root;
public BinaryTree() {
super();
// TODO 自动生成构造函数存根
root=this.createPre();
}
public BinaryNode createPre()
//按照先序遍历的输入方法，建立二叉树
{
BinaryNode t=null;
char ch;
try {
ch = (char)System.in.read();
if(ch==' ')
t=null;
else
{
t=new BinaryNode();
t.element=(Object)ch;
t.left=createPre();
t.right=createPre();
}
} catch (IOException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
}
return t;
}
public void inOrder()
{
this.inOrder(root);
}
public void inOrder(BinaryNode t)
//中序遍历二叉树
{
if(t!=null)
{
inOrder(t.left);
System.out.print(t.element);
inOrder(t.right);
}
}
public void postOrder()
{
this.postOrder(root);
}
public void postOrder(BinaryNode t)
//后序遍历二叉树
{
if(t!=null)
{
postOrder(t.left);
System.out.print(t.element);
postOrder(t.right);
}
}
public void preOrder()
{
this.preOrder(root);
}
public void preOrder(BinaryNode t)
//前序遍历二叉树
{
if(t!=null)
{
System.out.print(t.element);
preOrder(t.left);
preOrder(t.right);
}
}
public void breadthFirst()
{
Queue treeQueue=new Queue();
BinaryNode p;
if(root!=null)
treeQueue.enqueue(root);
while(!treeQueue.isEmpty())
{
System.out.print(((BinaryNode)(treeQueue.front())).element);
p=(BinaryNode)treeQueue.dequeue();
if(p.left!=null)
treeQueue.enqueue(p.left);
if(p.right!=null)
treeQueue.enqueue(p.right);
}
}
}
public class BinaryTreeTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO 自动生成方法存根
BinaryTree tree = new BinaryTree();
System.out.println("先序遍历：");
tree.preOrder();
System.out.println();
System.out.println("中序遍历：");
tree.inOrder();
System.out.println();
System.out.println("后序遍历：");
tree.postOrder();
System.out.println();
System.out.println("层次遍历：");
tree.breadthFirst();
System.out.println();
}
}
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);
}
}
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);
}
}
java一个关于二叉树的简单编程题
定义一个结点类：
public class Node {
private int value;
private Node leftNode;
private Node rightNode;
public Node getRightNode() {
return rightNode;
}
public void setRightNode(Node rightNode) {
this.rightNode = rightNode;
}
public int getValue() {
return value;
}
public void setValue(int value) {
this.value = value;
}
public Node getLeftNode() {
return leftNode;
}
public void setLeftNode(Node leftNode) {
this.leftNode = leftNode;
}
}
初始化结点树：
public void initNodeTree()
{
int nodeNumber;
HashMapString, Integer map = new HashMapString, Integer();
Node nodeTree = new Node();
Scanner reader = new Scanner(System.in);
nodeNumber = reader.nextInt();
for(int i = 0; i nodeNumber; i++) {
int value = reader.nextInt();
String str = reader.next();
map.put(str, value);
}
if (map.containsKey("#")) {
int value = map.get("#");
nodeTree.setValue(value);
setChildNode(map, value, nodeTree);
}
preTraversal(nodeTree);
}
private void setChildNode(HashMapString, Integer map, int nodeValue, Node parentNode) {
int value = 0;
if (map.containsKey("L" + nodeValue)) {
value = map.get("L" + nodeValue);
Node leftNode = new Node();
leftNode.setValue(value);
parentNode.setLeftNode(leftNode);
setChildNode(map, value, leftNode);
}
if (map.containsKey("R" + nodeValue)) {
value = map.get("R" + nodeValue);
Node rightNode = new Node();
rightNode.setValue(value);
parentNode.setRightNode(rightNode);
setChildNode(map, value, rightNode);
}
}
前序遍历该结点树：
public void preTraversal(Node nodeTree) {
if (nodeTree != null) {
System.out.print(nodeTree.getValue() + "\t");
preTraversal(nodeTree.getLeftNode());
preTraversal(nodeTree.getRightNode());
}
}
