Object Oriented Programming

GATE

Data Structures

Data Structures in Python

Power BI

Data Science

Django

Data Structure and Algorithm

Python

Recursion

Arrays

Searching

Sorting

String

Linked List

Data Structures in C

Maths

Strings

C++ Tricks

System Design

Theory of Computation

Computer Organization and Architecture

Operating System

Engineering Mathematics

Database

Digital Logic

Computer Networks

GATE 2022

Java

GeeksforGeeks School

Hashing

Competitive Programming

Problem of the Day

School

HTML

Javascript

Bootstrap

Web Development

Android

Microsoft Office

Machine Learning

Resume Builder

Miscellaneous

Gblog

TechTips

React

Advanced JavaScript

DSA Self Paced

CS-subjects

Data Structures and Algorithms

Operating Systems

C Language

DBMS

Basics of CPP

Data Structures ( Basics )

Object Oriented Design

Dynamic Programming

Data Interpretation and Logical Reasoning

Algorithms

Core Java

RESTful APIs

Spring Basics

CPP-Tricks

Basics of Java

Aptitude

GATE YT

Flutter

Application Development

Blockchain

GFG SDE Sheet

SDE Sheet

Deep Learning

Go Programming

Placement

C++ Programs

Data Visualisation

DevOps

Docker

Queue

Matrix

Trie

Stack

Graph

Tree

Magic Numbers

Divide and Conquer

React Native

React JS

Interview-Questions

Advanced Java

cloud-computing

income tax

Artificial Intelligence

Programming Languages

Computer Graphics

Cyber Security

Project Management

DSA / Placements

GATE Prep

Data Analytics / Data Science

Development

Cloud / DevOps

All Courses

Courses

ML & Data Science

Interview Corner

CS Subjects

School Learning

Software and Tools

Tutorials

Google Build with AI

Practice Coding Problems

Connect 1:1 with Experts

Practice

Apply Now!

Post Jobs

Jobs Updates

Jobs

It is known that in level order traversal of binary tree with queue, at any time our queue contains all elements of a particular level. So find level with maximum number of nodes in queue.&nbsp; BFS traversal is an algorithm for traversing or searching tree or graphs . It starts at the tree root , and explores all of the neighbor nodes at the present depth prior to moving on to the nodes at the next depth level.&nbsp; So at any point the queue of BFS will contain elements of adjacent layers. So this makes the algorithm perfect for this problem.Algorithm:&nbsp;<ol><li>Create the tree, a queue to store the nodes and insert the root in the queue. Create variables level=0,count =0 and level_no=-1</li><li>The implementation will be slightly different, all the elements of same level will be removed in a single iteration.</li><li>Run a loop while size of queue is greater than 0. Get the size of queue (size) and store it. If size is greater than count then update count = size and level_no = level.</li><li>Now run a loop size times, and pop one node from the queue and insert its childrens (if present).</li><li>Increment level.</li></ol>Level with maximum number of nodes :<a href="https://www.geeksforgeeks.org/level-maximum-number-nodes/">https://www.geeksforgeeks.org/level-maximum-number-nodes/</a>

Level with maximum number of nodes

a different approach using two queues is discussed. We can insert the first level in first queue and print it and while popping from the first queue insert its left and right nodes into the second queue. Now start printing the second queue and before popping insert its left and right child nodes into the first queue. Continue this process till both the queues become empty.Level order traversal line by line &nbsp;Set 2 (Using Two Queues): <a href="https://www.geeksforgeeks.org/level-order-traversal-line-line-set-2-using-two-queues/">https://www.geeksforgeeks.org/level-order-traversal-line-line-set-2-using-two-queues/</a>

Level order traversal line by line | Set 2 (Using Two Queues)

The idea is to traverse tree level by level. For each level, we count number of nodes in it and print its leftmost or the rightmost node based on value of a Boolean flag. We dequeue all nodes of current level and enqueue all nodes of next level and invert value of Boolean flag when switching levels.Print extreme nodes of each level of Binary Tree in alternate order: <a href="https://www.geeksforgeeks.org/print-extreme-nodes-of-each-level-of-binary-tree-in-alternate-order/">https://www.geeksforgeeks.org/print-extreme-nodes-of-each-level-of-binary-tree-in-alternate-order/</a>

Print extreme nodes of each level of Binary Tree in alternate order

a different approach using one queue is discussed. First insert the root and a null element into the queue. This null element acts as a delimiter. Next, pop from the top of the queue and add its left and right nodes to the end of the queue and then print at the top of the queue. Continue this process till the queues become empty.Level order traversal line by line &nbsp;Set 3 (Using One Queue): <a href="https://www.geeksforgeeks.org/level-order-traversal-line-line-set-3-using-one-queue/">https://www.geeksforgeeks.org/level-order-traversal-line-line-set-3-using-one-queue/</a>

Level order traversal line by line | Set 3 (Using One Queue)

Given an array of elements, our task is to construct a complete binary tree from this array in a level order fashion. That is, elements from the left in the array will be filled in the tree level-wise starting from level 0. Examples:&nbsp; &nbsp;Input &nbsp;: &nbsp;arr[] = {1, 2, 3, 4, 5, 6} Output : Root of the following tree &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;1 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; / \ &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;2 &nbsp; 3 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; / \ / &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;4 &nbsp;5 6&nbsp;Construct a complete binary tree from given array in level order fashion : <a href="https://www.geeksforgeeks.org/construct-complete-binary-tree-given-array/">https://www.geeksforgeeks.org/construct-complete-binary-tree-given-array/</a>

Construct a complete binary tree from given array in level order fashion

Write a recursive program for level order traversal of a tree. Traverse each level of both the trees one by one and store the result of traversals in 2 different vectors, one for each tree. Sort both the vectors and compare them iteratively for each level, if they are same for each level then return true else return false. Time Complexity: O(n^2), where n is the number of nodes. Check if all levels of two trees are anagrams or not &nbsp; : <a href="https://www.geeksforgeeks.org/check-if-all-levels-of-two-trees-are-anagrams-or-not/">https://www.geeksforgeeks.org/check-if-all-levels-of-two-trees-are-anagrams-or-not/</a>

Check if all levels of two trees are anagrams or not

There are basically two functions in this method. One is to print all nodes at a given level (printCurrentLevel), and the other is to print the level order traversal of the tree (printLevelorder).&nbsp;printLevelorder makes use of printCurrentLevel to print nodes at all levels one by one starting from the root.General Tree Level Order Traversal : <a href="https://www.geeksforgeeks.org/level-order-tree-traversal/">https://www.geeksforgeeks.org/level-order-tree-traversal/</a>

General Tree Level Order Traversal

a recursive method have been discussed. In this post an iterative method has been discussed. The idea is to perform iterative level order traversal of the binary tree using queue. While traversing keep max variable which stores the maximum element of the current level of the tree being processed. When the level is completely traversed, print that max value. &nbsp;Largest value in each level of Binary Tree &nbsp;Set-2 (Iterative Approach) : <a href="https://www.geeksforgeeks.org/largest-value-level-binary-tree-set-2-iterative-approach/">https://www.geeksforgeeks.org/largest-value-level-binary-tree-set-2-iterative-approach/</a>

Largest value in each level of Binary Tree | Set-2 (Iterative Approach)

Given a tree, print the level order traversal in sorted order. Examples :&nbsp; &nbsp;Input : &nbsp; &nbsp; 7 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;/ &nbsp; &nbsp;\ &nbsp; &nbsp; &nbsp; &nbsp;6 &nbsp; &nbsp; &nbsp; 5 &nbsp; &nbsp; &nbsp; / \ &nbsp; &nbsp; / \ &nbsp; &nbsp; &nbsp;4 &nbsp;3 &nbsp; &nbsp;2 &nbsp; 1 Output :&nbsp; 7 5 6 1 2 3 4 Print Binary Tree levels in sorted order &nbsp;Set 2 (Using set): <a href="https://www.geeksforgeeks.org/print-binary-tree-levels-sorted-order-2/">https://www.geeksforgeeks.org/print-binary-tree-levels-sorted-order-2/</a>

Print Binary Tree levels in sorted order | Set 2 (Using set)

The idea is to recursively traverse trees in an in-order fashion. The root is considered to be at the zeroth level. First, find the height of the tree and store it into res. res array store every smallest element in each level of a binary tree. Input :&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;7 &nbsp; &nbsp; &nbsp; &nbsp; / &nbsp; &nbsp;\ &nbsp; &nbsp; &nbsp; &nbsp;6 &nbsp; &nbsp; &nbsp; 5 &nbsp; &nbsp; &nbsp; / \ &nbsp; &nbsp; / \ &nbsp; &nbsp; &nbsp;4 &nbsp;3 &nbsp; &nbsp; 2 &nbsp;1 &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; Output :&nbsp; Every level minimum is level 0 min is = 7 level 1 min is = 5 level 2 min is = 1Smallest value in each level of Binary Tree: <a href="https://www.geeksforgeeks.org/smallest-value-level-binary-tree/">https://www.geeksforgeeks.org/smallest-value-level-binary-tree/</a>

Smallest value in each level of Binary Tree

The idea is to recursively traverse tree in a pre-order fashion. Root is considered to be at zeroth level. While traversing, keep track of the level of the element and if its current level is not equal to the number of elements present in the list, update the maximum element at that level in the list.Largest value in each level of Binary Tree: <a href="https://www.geeksforgeeks.org/largest-value-level-binary-tree/">https://www.geeksforgeeks.org/largest-value-level-binary-tree/</a>

Largest value in each level of Binary Tree

The above code prints nodes in preorder way. If we wish to print nodes level by level, we can use level order traversal. The idea is based on Print level order traversal line by line We traverse nodes level by level. We switch odd level flag after every level.Print the nodes at odd levels of a tree : <a href="https://www.geeksforgeeks.org/print-nodes-odd-levels-tree/">https://www.geeksforgeeks.org/print-nodes-odd-levels-tree/</a>

Print the nodes at odd levels of a tree

Practice Problems

JavaScript

Linux