This tutorial provides a Java program to print nodes of Binary Tree that will be visible from right view.

Understanding Right View of a Binary Tree

Right View of a Binary Tree consists of nodes that are visible from Right side of a Binary Tree. This requires level order traversal and printing first node from right side at each level.

Let's consider below Binary Tree - 

Here is the right view of above Binary tree -

50 
70 
80 
90 

Java Implementation of Right View of a Binary Tree

Here is Java code for Binary Tree containing methods for inserting data and printing right view of Binary Tree - 

package com.aksain.data.structures;

import java.util.LinkedList;
import java.util.Queue;

public class BinaryTreeWithRightView<T extends Comparable<T>> {
	private Node root;

	private class Node {
		T data;
		Node left;
		Node right;

		private Node(T data) {
			this.data = data;
		}
	}

	private Node doInsert(T data, Node node) {
		if (node == null) {
			return new Node(data);
		}
		int result = data.compareTo(node.data);
		if (result < 0) {
			node.left = doInsert(data, node.left);
		} else if (result > 0) {
			node.right = doInsert(data, node.right);
		}

		return node;
	}

	public void insert(T data) {
		root = doInsert(data, root);
	}

	private void doPrintRightView(Node root) {
		final Queue<Node> queue = new LinkedList<>();
		queue.add(root);
		
		while(!queue.isEmpty()) {
			int noOfElementsAtThisLevel = queue.size();
			for(int index = 0; index < noOfElementsAtThisLevel; index++) {
				Node tmp = queue.poll();
				if(index == noOfElementsAtThisLevel - 1) {
					System.out.print(tmp.data + " ");	
				}
				
				if(tmp.left != null) {
					queue.add(tmp.left);
				}
				if(tmp.right != null) {
					queue.add(tmp.right);
				}
			}
			System.out.println();
		}
	}

	public void printRightView() {
		doPrintRightView(root);
	}

	public static void main(String[] args) {
		final BinaryTreeWithRightView<Integer> binaryTree = new BinaryTreeWithRightView<>();
		binaryTree.insert(50);
		binaryTree.insert(30);
		binaryTree.insert(10);
		binaryTree.insert(20);
		binaryTree.insert(40);
		binaryTree.insert(70);
		binaryTree.insert(60);
		binaryTree.insert(80);
		binaryTree.insert(90);

		binaryTree.printRightView();
	}

}

Here is the output of above code - 

50 
70 
80 
90 

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