Java中的二叉树不使用add方法

Question

我一直在尝试从 Node 切换到 Java，我想知道的一件事是如何在不放入排序算法的情况下构造二叉树。在 Node 中，我可以简单地键入以下内容：

function TreeNode(val) {
    this.val = val;
    this.left = this.right = null;
}
let tree = new TreeNode(4);
tree.left = new TreeNode(2);
tree.left.left = new TreeNode(1);

Java 相当于什么？这是我目前的思考过程

public class BinaryTree {
    private static TreeNode root;
    public static void main(String[] args) {
        BinaryTree bt = new BinaryTree();
        bt.TreeNode = ??

    }

  public class TreeNode {
      int val;
      TreeNode left;
      TreeNode right;
      TreeNode(int x) { val = x; }
  }

}

Answer 1

@EJP：不需要两个类。每个树节点都是一棵树。

OP：你能用一节课告诉我这个吗？

基于代码https://stackoverflow.com/a/50072165/139985 ....

public class BinaryTree {
    int data;
    BinaryTree left, right;

    public BinaryTree(int data) {
        super();
        this.data = data;
        this.left = this.right = null; // redundant ...
    }

    public int height() {
        height(this);
    }

    private int height(BinaryTree node) {
        if (node == null) {
            return 0;
        }
        return Math.max(height(node.left), height(node.right)) + 1;
    }

    public static void main(String[] args) {
        BinaryTree tree = new BinaryTree(1);
        tree.left = new BinaryTree(2);
        tree.right = new BinaryTree(3);
        tree.left.right = new BinaryTree(4);

        System.out.println("The height of given binary tree is : " + tree.height());
    }

}

Answer 2

你可以像这样构造你的代码

class Node {
    int data;
    Node left, right;

    public Node(int data) {
        super();
        this.data = data;
        this.left = this.right = null;
    }

}

public class BinaryTree {
    Node root;

    public int height(Node node) {
        if (node == null)
            return 0;
        return Math.max(height(node.left), height(node.right)) + 1;
    }

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

        System.out.println("The height of given binary tree is : " + tree.height(tree.root));
    }

}