Minimum nodes for same right view in Binary tree

// C# code to find the minimum number of nodes to remove 
// to keep the right view of a binary tree the same.

using System;
using System.Collections.Generic;

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

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

class GfG {
    // Traverse the tree
    static void Traverse(Node node, int level, List<int> rightmost) {
        if (node == null) {
            return;
        }

        if (rightmost.Count == level) {
            rightmost.Add(node.data);
        }

        Traverse(node.right, level + 1, rightmost);
        Traverse(node.left, level + 1, rightmost);
    }

    // Minimum nodes we can remove to keep right view same
    static public int CountToRemove(Node node, int level, List<int> rightmost) {
        if (node == null) {
            return 0;
        }

        int count = 0;

        if (node.left != null) {
            count += CountToRemove(node.left, level + 1, rightmost);
            if (rightmost[level] != node.data) {
                count++;
            }
        }

        if (node.right != null) {
            count += CountToRemove(node.right, level + 1, rightmost);
            if (rightmost[level] != node.data) {
                count++;
            }
        }

        // Return the number of nodes that can be removed
        return count;
    }

    static public int MinNodesToRemove(Node root) {
        List<int> rightmost = new List<int>();
        Traverse(root, 0, rightmost);
        return CountToRemove(root, 0, rightmost);
    }
	static void Main(string[] args) {
        // Constructing binary tree.
        //      1
        //     / \
        //    2   3
        //     \   \
        //      8   5
        //       \
        //        6

        Node root = new Node(1);
        root.left = new Node(2);
        root.left.right = new Node(8);
        root.left.right.right = new Node(6);
        root.right = new Node(3);
        root.right.right = new Node(5);

        // Function call
        Console.WriteLine(MinNodesToRemove(root));
    }
}