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);    }}