// C# program to connect nodes at same level 

using System; 

using System.Collections.Generic; 

​

class Node 

{ 

    public int data; 

    public Node left, right, nextRight; 

​

    public Node(int item) 

    { 

        data = item; 

        left = right = nextRight = null; 

    } 

} 

​

public class BinaryTree 

{ 

    Node root; 

    void connect(Node p) 

    { 

        // initialize queue to hold nodes at same level 

        Queue<Node> q = new Queue<Node>(); 

​

        q.Enqueue(root); // adding nodes to tehe queue 

​

        Node temp = null; // initializing prev to null 

        while (q.Count > 0) 

        { 

            int n = q.Count; 

            for (int i = 0; i < n; i++) 

            { 

                Node prev = temp; 

                temp = q.Dequeue(); 

​

                // i > 0 because when i is 0 prev points 

                // the last node of previous level, 

                // so we skip it 

                if (i > 0) 

                    prev.nextRight = temp; 

​

                if (temp.left != null) 

                    q.Enqueue(temp.left); 

​

                if (temp.right != null) 

                    q.Enqueue(temp.right); 

            } 

​

            // pointing last node of the nth level to null 

            temp.nextRight = null; 

        } 

    } 

​

    // Driver code 

    public static void Main(String[] args) 

    { 

        BinaryTree tree = new BinaryTree(); 

​

        /* Constructed binary tree is 

            10 

            / \ 

        8    2 

        / 

        3 

        */

        tree.root = new Node(10); 

        tree.root.left = new Node(8); 

        tree.root.right = new Node(2); 

        tree.root.left.left = new Node(3); 

​

        // Populates nextRight pointer in all nodes 

        tree.connect(tree.root); 

​

        // Let us check the values of nextRight pointers 

        Console.WriteLine("Following are populated nextRight pointers in "

                        + "the tree"

                        + "(-1 is printed if there is no nextRight)"); 

        int a = tree.root.nextRight != null ? tree.root.nextRight.data : -1; 

        Console.WriteLine("nextRight of " + tree.root.data + " is "

                        + a); 

        int b = tree.root.left.nextRight != null ? tree.root.left.nextRight.data : -1; 

        Console.WriteLine("nextRight of " + tree.root.left.data + " is "

                        + b); 

        int c = tree.root.right.nextRight != null ? tree.root.right.nextRight.data : -1; 

        Console.WriteLine("nextRight of " + tree.root.right.data + " is "

                        + c); 

        int d = tree.root.left.left.nextRight != null ? tree.root.left.left.nextRight.data : -1; 

        Console.WriteLine("nextRight of " + tree.root.left.left.data + " is "

                        + d); 

​

    } 

} 

​

​