BST — inorder traversal sum #19

using System;
using System.Collections.Generic;

class Node { public int Val; public Node L, R; public Node(int v) => Val = v; }
class Program {
    static void Main() {
        var root = new Node(2) { L = new Node(1), R = new Node(3) };
        int sum = 0;
        void Dfs(Node n) { if (n == null) return; Dfs(n.L); sum += n.Val; Dfs(n.R); }
        Dfs(root);
        Console.WriteLine(sum);
    }
}