线索化二叉树

public class ThreadedBinaryTreeDemo {

    public static void main(String[] args) {
        ThreadedBinaryTree threadedBinaryTree = new ThreadedBinaryTree();

        Node one = new Node(1);
        Node three = new Node(3);
        Node six = new Node(6);
        Node eight = new Node(8);
        Node ten = new Node(10);
        Node fourteen = new Node(14);
        Node fifteen = new Node(15);
        Node two = new Node(2);

        /*
                    创建二叉树：
                                1
                              /   \
                             3     6
                            / \   / \
                           8  10 14  15
                                 /
                                2
         */
        threadedBinaryTree.setRoot(one);
        one.left = three;
        one.right = six;
        three.left = eight;
        three.right = ten;
        six.left = fourteen;
        six.right = fifteen;
        fourteen.left = two;


        threadedBinaryTree.threadedBinaryTree();
        System.out.println("线索化二叉树结果：");
        threadedBinaryTree.infixOrder();

    }

}

class ThreadedBinaryTree {
    public Node root;
    public Node pre = null;

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

    public void threadedBinaryTree() {
        threadedBinaryTree(this.root);
    }

    public void threadedBinaryTree(Node current) {
        if (current == null) {
            return;
        }
        //线索化当前节点的左子节点
        threadedBinaryTree(current.left);
        //线索化当前节点
        if (current.left == null) {
            current.left = pre;
            current.leftType = 1;
        }
        if (pre != null && pre.right == null) {
            pre.right = current;
            pre.rightType = 1;
        }
        pre = current;
        //线索化当前节点的右子节点
        threadedBinaryTree(current.right);
    }

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

}

class Node {
    public int num;
    public Node left;
    public Node right;
    public int leftType;
    public int rightType;

    public Node(int num) {
        this.num = num;
    }

    @Override
    public String toString() {
        return num + "";
    }

    public void infixOrder() {
        if(this.left != null) {
            if (this.leftType == 0) {
                this.left.infixOrder();
            } else {
                System.out.print(this.left.num);
            }
        }

        if(!(this.leftType == 0 && this.rightType == 0)){
            System.out.print("<=" + num + "=>");
        }

        if(this.right != null){
            if (this.rightType == 0) {
                this.right.infixOrder();
            } else {
                System.out.println(this.right.num);
            }
        }
    }

}