Untitled

import java.util.*;
class TreeNode
{
    int val;
    TreeNode left, right;
    
    TreeNode(int val)
    {
        this.val = val;
        left=right=null;
    }
}


public class Main
{
    public static void main(String[] args) {
        // System.out.println("Welcome to Online IDE!! Happy Coding :)");
        
        TreeNode root = new TreeNode(1);
        root.left = new TreeNode(2);
        root.right = new TreeNode(3);
        root.left.right = new TreeNode(4);
        root.left.right.left = new TreeNode(5);
        root.right.left = new TreeNode(6);
        
        List<Integer> arr = new ArrayList<>();
        
        rightSideView (root, 0, arr);
        System.out.println(arr);
    }
    
    
    public static void rightSideView(TreeNode root, int level, List<Integer> arr)
    {
        if(root==null) return;
        
        if(level==arr.size()) arr.add(root.val); 
        
        rightSideView(root.right, level+1, arr);
        rightSideView(root.left, level+1, arr);
        
    }
}