java数据结构树的实现例子

Tree类：树的结构类：

package com.qsf.dataStructure.tree;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * 树的定义
 */
public class Tree {

    private Object data;
    private List childs;

    public Tree(){
        data = null;
        childs = new ArrayList<>();
        childs.clear();
    }
    public Tree(Object data) {
        this.data = data;
        childs = new ArrayList();
        childs.clear();
    }
    /**
     * 添加子树
     * @param tree
     */
    public void addNode(Tree tree){
        childs.add(tree);
    }

    /**
     *   置空树
     */
    public void clearTree(){
        data = null;
        childs.clear();
    }
    /**
     * 求树的深度
      */
    public int dept(){
        return dept(this);
    }
    /**
     * 求树的深度
      */
    public int dept(Tree tree){
        if(tree.isEmpty()) {
            return 0;
        }else if(tree.isLeaf()) {
            return 1;
        } else {
            int n = tree.childs.size();
            int[] a = new int[n];
            for(int i=0; i getChilds() {
        return childs;
    }

    /**
     * 获得根结点的数据
     * @return
     */
    public Object getRootData() {
        return data;
    }

    /**
     * 判断是否为空树
     * @return 如果为空，返回true,否则返回false
     */
    public boolean isEmpty() {
        if(childs.isEmpty() && data == null) {
            return true;
        }
        return false;
    }

    /**
     * 判断是否为叶子结点
     * @return
     */
    public boolean isLeaf() {
        if(childs.isEmpty())
            return true;
        return false;
    }

    /**
     * 获得树根
     * @return 树的根
     */
    public Tree root() {
        return this;
    }

    /**
     * 设置根结点的数据
     */
    public void setRootData(Object data) {
        this.data = data;
    }

    /**
     * 求结点数
     * @return 结点的个数
     */
    public int size() {
        return size(this);
    }
    /**
     * 求结点数
     * @param tree
     * @return
     */
    private int size(Tree tree) {
        if(tree.isEmpty()) {
            return 0;
        }else if(tree.isLeaf()) {
            return 1;
        } else {
            int count = 1;
            int n = tree.childs.size();
            for(int i=0; i

order类：遍历树的结构

package com.qsf.dataStructure.tree;

public class Order {
    /**
     * 先根遍历
     * @param root 要的根结点
     */
    public void preOrder(Tree root) {
        if(!root.isEmpty()) {
            visit(root);
            for(Tree child : root.getChilds()) {
                if(child != null) {
                    preOrder(child);
                }
            }
        }
    }
    /**
     * 后根遍历
     * @param root 树的根结点
     */
    public void postOrder(Tree root) {
        if(!root.isEmpty()) {
            for(Tree child : root.getChilds()) {
                if(child != null) {
                    preOrder(child);
                }
            }
            visit(root);
        }
    }

    public void visit(Tree tree) {
        System.out.print("\t" + tree.getRootData());
    }
}

TreeTest类：测试类 

package com.qsf.dataStructure.tree;

public class TreeTest {
    public static void main(String[] args) {
        Tree root = new Tree("A");
        root.addNode(new Tree("B"));
        root.addNode(new Tree("C"));
        root.addNode(new Tree("D"));
        Tree t = null;
        t = root.getChild(0);
        t.addNode(new Tree("L"));
        t.addNode(new Tree("E"));
        t = root.getChild(1);
        t.addNode(new Tree("F"));
        t = root.getChild(2);
        t.addNode(new Tree("I"));
        t.addNode(new Tree("H"));
        t = t.getFirstChild();
        t.addNode(new Tree("L"));

        System.out.println("first node:" + root.getFirstChild());
        System.out.println("first node:" + root.getLastChild());
        System.out.println("size:" + root.size());
        System.out.println("dept:" + root.dept());
        System.out.println("is left:" + root.isLeaf());
        System.out.println("data:" + root.getRootData());

        Order order = new Order();
        System.out.println("前根遍历：");
        order.preOrder(root);
        System.out.println("\n后根遍历：");
        order.postOrder(root);
    }
}