Qz学算法-数据结构篇(非线性结构、树)

package tree;

/**
 * @author LeeZhi
 * @version 1.0
 */
public class BinaryTreeDemo {
    public static void main(String[] args) {
        //先创建一个二叉树
        BinaryTree binaryTree = new BinaryTree();
        //创建需要的节点
        HeroNode root = new HeroNode(1, "宋江");
        HeroNode node2 = new HeroNode(2, "吴用");
        HeroNode node3 = new HeroNode(3, "卢俊义");
        HeroNode node4 = new HeroNode(4, "李逵");
        HeroNode node5 = new HeroNode(5, "武松");

        //说明,我们先手动创建该二叉树，后面我们学习递归的方式创建二叉树
        root.setLeft(node2);
        root.setRight(node3);
        node3.setRight(node4);
        node3.setLeft(node5);
        binaryTree.setRoot(root);
        //测试,前序遍历
        System.out.println("前序遍历");
        binaryTree.preOrder();

        System.out.println("中序遍历");
        binaryTree.infixOrder();

        System.out.println("后续遍历");
        binaryTree.postOrder();

    }
}

//定义 BinaryTree 二叉树
class BinaryTree{
    private HeroNode root;

    public void setRoot(HeroNode root) {
        this.root = root;
    }

    //前序遍历
    public void preOrder(){
        if (this.root!=null){
            this.root.preOrder();
        }else{
            System.out.println("二叉树为空,无法遍历");
        }
    }

    //中序遍历
    public void infixOrder(){
        if (this.root!=null){
            this.root.infixOrder();
        }else{
            System.out.println("二叉树为空,无法遍历");
        }
    }

    //后序遍历
    public void postOrder(){
        if (this.root!=null){
            this.root.postOrder();
        }else{
            System.out.println("二叉树为空,无法遍历");
        }
    }
}


class HeroNode{
    private int no;
    private String name;
    private HeroNode left; //默认null
    private HeroNode right; //默认null

    public HeroNode(int no, String name) {
        super();
        this.no = no;
        this.name = name;
    }

    public int getNo() {
        return no;
    }

    public void setNo(int no) {
        this.no = no;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public HeroNode getLeft() {
        return left;
    }

    public void setLeft(HeroNode left) {
        this.left = left;
    }

    public HeroNode getRight() {
        return right;
    }

    public void setRight(HeroNode right) {
        this.right = right;
    }

    @Override
    public String toString() {
        return "HeroNode{" +
                "no=" + no +
                ", name='" + name + ''' +
                '}';
    }

    //编写前序遍历的方法
    public void preOrder(){
        System.out.println(this);//先输出父节点
        //递归想左子树前序遍历
        if (this.left!=null){
            this.left.preOrder();
        }
        //递归向右子树前序遍历
        if (this.right!=null){
            this.right.preOrder();
        }
    }
    //中序遍历
    public void infixOrder(){
        //先递归向左子树中序遍历
        if (this.left!=null){
            this.left.infixOrder();
        }
        //输出父节点
        System.out.println(this);
        //递归向右子树中序遍历
        if (this.right!=null){
            this.right.infixOrder();
        }
    }
    //后序遍历
    public void postOrder(){
        if (this.left!=null){
            this.left.postOrder();
        }
        if (this.right!=null){
            this.right.postOrder();
        }
        System.out.println(this);
    }
}