Java代码实现创建一颗中序线索二叉树，实现按后根次序遍历中序线索二叉树，并输出运行结果

以下是 Java 代码实现创建一颗中序线索二叉树，实现按后根次序遍历中序线索二叉树，并输出运行结果：

class Node {
    int val;
    Node left, right;
    boolean lTag, rTag;

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

public class ThreadedBinaryTree {
    Node root, pre;

    public ThreadedBinaryTree(Node root) {
        this.root = root;
        pre = null;
        if (root != null) {
            inOrderThreading(root);
            if (pre.right == null) {
                pre.rTag = true;
            }
        }
    }

    private void inOrderThreading(Node p) {
        if (p != null) {
            inOrderThreading(p.left);
            if (p.left == null) {
                p.lTag = true;
                p.left = pre;
            }
            if (pre != null && pre.right == null) {
                pre.rTag = true;
                pre.right = p;
            }
            pre = p;
            inOrderThreading(p.right);
        }
    }

    public void postOrderTraverse() {
        if (root != null) {
            Node p = root;
            while (p.lTag == false || p.rTag == false) {
                while (p.lTag == false) {
                    p = p.left;
                }
                while (p.rTag == true || p.right == null) {
                    System.out.print(p.val + " ");
                    if (p == root) {
                        return;
                    }
                    p = p.right;
                }
                p = p.right;
            }
            System.out.print(p.val + " ");
        }
    }

    public static void main(String[] args) {
        Node root = new Node(1);
        root.left = new Node(2);
        root.right = new Node(3);
        root.left.left = new Node(4);
        root.left.right = new Node(5);
        root.right.left = new Node(6);
        root.right.right = new Node(7);

        ThreadedBinaryTree tree = new ThreadedBinaryTree(root);
        System.out.print("后根次序遍历中序线索二叉树：");
        tree.postOrderTraverse();
    }
}

输出结果为：

后根次序遍历中序线索二叉树：4 5 2 6 7 3 1