Connect nodes at same level

// C# Program to Connect Nodes at same Level

using System;
using System.Collections.Generic;

class Node {
    public int data;
    public Node left;
    public Node right;
    public Node nextRight;

    public Node(int val) {
        data = val;
        left = null;
        right = null;
        nextRight = null;
    }
}

class GfG {

    // Sets the nextRight of root and calls
    // connectRecur() for other nodes
    static void connect(Node root) {
      
        // Set the nextRight for root
        root.nextRight = null;

        // Set the next right for rest of the nodes
        // (other than root)
        connectRecur(root);
    }

    // Set next right of all descendants of root.
    // Assumption: root is a complete binary tree
    static void connectRecur(Node root) {
        if (root == null)
            return;

        // Set the nextRight pointer for root's left child
        if (root.left != null)
            root.left.nextRight = root.right;

        // Set the nextRight pointer for root's right child
        // root.nextRight will be null if root is the
        // rightmost child at its level
        if (root.right != null)
            root.right.nextRight = (root.nextRight != null)
                                       ? root.nextRight.left
                                       : null;

        // Set nextRight for other nodes in
        // pre-order fashion
        connectRecur(root.left);
        connectRecur(root.right);
    }

    // Function to store the nextRight pointers in
    // level-order format and return as a list of strings
    static List<string> getNextRightArray(Node root) {
        List<string> result = new List<string>();
        if (root == null)
            return result;

        Queue<Node> queue = new Queue<Node>();
        queue.Enqueue(root);
        queue.Enqueue(null);

        while (queue.Count > 0) {
            Node node = queue.Dequeue();

            if (node != null) {

                // Add the current node's data
                result.Add(node.data.ToString());

                // If nextRight is null, add '#'
                if (node.nextRight == null) {
                    result.Add("#");
                }

                // Push the left and right children to the
                // queue (next level nodes)
                if (node.left != null)
                    queue.Enqueue(node.left);
                if (node.right != null)
                    queue.Enqueue(node.right);
            }
            else if (queue.Count > 0) {

                // Add level delimiter for the next level
                queue.Enqueue(null);
            }
        }

        return result;
    }

    static void Main(string[] args) {

        // Constructed binary tree is
        //       10
        //      / \
        //     8   2
        //    /
        //   3

        Node root = new Node(10);
        root.left = new Node(8);
        root.right = new Node(2);
        root.left.left = new Node(3);

        connect(root);
        List<string> output = getNextRightArray(root);
        foreach(string s in output) {
            Console.Write(s + " ");
        }
        Console.WriteLine();
    }
}