使用二进制搜索树数据在java中递归地构建字符串

// 节点类
class Node {
    int value;
    Node left;
    Node right;

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

// 树类
class BinarySearchTree {
    Node root;

    public BinarySearchTree() {
        this.root = null;
    }

    // 递归构建字符串
    private String buildStringRecursive(Node node) {
        if (node == null) {
            return "";
        }

        String result = String.valueOf(node.value);
        String leftString = buildStringRecursive(node.left);
        String rightString = buildStringRecursive(node.right);

        result += leftString + rightString;

        return result;
    }

    // 构建字符串的入口方法
    public String buildString() {
        return buildStringRecursive(root);
    }
}

// 测试代码
public class Main {
    public static void main(String[] args) {
        BinarySearchTree tree = new BinarySearchTree();
        tree.root = new Node(4);
        tree.root.left = new Node(2);
        tree.root.right = new Node(6);
        tree.root.left.left = new Node(1);
        tree.root.left.right = new Node(3);
        tree.root.right.left = new Node(5);
        tree.root.right.right = new Node(7);

        String result = tree.buildString();
        System.out.println(result);
    }
}