二叉树前序中序后序遍历

二叉树前序中序后序遍历

package jiegou.tree;

public class BinaryTreeDemo {
    public static void main(String[] args) {
        //  先创建一颗二叉树
        BinaryTree binaryTree = new BinaryTree();
        HeroNode root = new HeroNode(1, "松江");
        HeroNode node2 = new HeroNode(2, "吴用");
        HeroNode node3 = new HeroNode(3, "卢俊义");
        HeroNode node4 = new HeroNode(4, "林冲");

        // 先手动创建二叉树
        root.setLeft(node2);
        root.setRight(node3);
        node3.setRight(node4);
        binaryTree.setRoot(root);

        System.out.println("前序遍历");
        binaryTree.preOrder();

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

        System.out.println("后序遍历");
        binaryTree.rightOrder();
    }
}
// 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");
        }
    }

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

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


//创建 heroNode

class HeroNode
{
    private int no;
    private String name;
    private HeroNode left;
    private HeroNode right;


    public HeroNode(int no, String name) {
        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 + '\'' +
                '}';
    }

    public void preOrder()
    {
        System.out.println(this); //父节点
        if(this.left!=null){
            this.left.preOrder();
        }

        if(this.right !=null){
            this.right.preOrder();
        }
    }

    public void infixOrder()
    {
        // 先左
        if(this.left!=null){
            this.left.infixOrder();
        }
        System.out.println(this);
        if(this.right !=null){
            this.right.infixOrder();
        }
    }

    public void rightOrder()
    {
        // 先左
        if(this.left!=null){
            this.left.rightOrder();
        }

        if(this.right !=null){
            this.right.rightOrder();
        }

        System.out.println(this);
    }
}

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