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二叉树旋转代码java，二叉树翻转java
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怎么用Java语言来实现二叉树啊？我现在编了一个程序却不能运行出结果，谁能帮我！
终止搞定，inorder和postorder分别是中序和后序
public class Test
{
static String inorder = "287413695";//"BDEFACHG"; //已知中序
static String postorder = "874296531";//"FEDBHGCA"; //已知后序
static Node root;
static class Node
{
public Node(char divideChar)
{
this.data = divideChar;
}
Node left;
Node right;
char data;
}
static Node divide(String in,String post,Node node)
{
if (in == null || in.length() 1 || post == null || post.length() 1)
return null;
String left = "";
char divideChar = post.charAt(post.length()-1);
if(in.indexOf(divideChar) != -1)
left = in.substring(0, in.indexOf(divideChar));
String right = in.substring(in.indexOf(divideChar) + 1);
if(node == null)
root = node = new Node(divideChar);
else
node = new Node(divideChar);
if (left != null)
{
if(left.length() 1)
node.left = divide(left, post.substring(0,left.length()),node);
else if(left.length() == 1)
node.left = new Node(left.charAt(0));
}
if (right != null)
{
if(right.length() 1)
node.right = divide(right, post.substring(left.length(),post.length()-1),node);
else if(right.length() == 1)
node.right = new Node(right.charAt(0));
}
return node;
}
static void preorder(Node node)
{
if(node == null) return;
System.out.println(node.data);
if(node.left != null) preorder(node.left);
if(node.right != null) preorder(node.right);
}
public static void main(String[] args)
{
root = divide(inorder, postorder,root);
preorder(root); //打印前序
}
}
相关问答
Q1: 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());
}
Q2: 如何用java实现二叉树
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);
}
}
输出结果：
前序遍历：
1 2 4 8 9 5 3 6 7
中序遍历：
8 4 9 2 5 1 6 3 7
后序遍历：
8 9 4 5 2 6 7 3 1
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