AfterAcademy Blog and Publication

Average of Levels in Binary Tree

Given a binary tree, write a program to return the average value of the nodes on each level in the form of an array. The range of the node's value is in the range of 32-bit signed integer.

Admin AfterAcademy 5 Nov 2020

Find The Height Of a Binary Tree

Given a binary tree, write a program to find the maximum depth of the binary tree. The maximum depth is the number of nodes along the longest path from the root node to the leaf node. A leaf is a node with no child nodes.

Admin AfterAcademy 3 Nov 2020

LRU Cache Implementation

Design and implement a data structure for Least Recently Used(LRU) cache. Your data structure must support two operations: get(key) and put(). The problem expects a constant time solution

Admin AfterAcademy 13 Oct 2020

Letter Combinations of a Phone Number

Given a string str, containing digits from 2 - 9 inclusive, write a program to return all the possible letter combinations that the number could represent. This is a popular coding interview question based on backtracking and recursive approach.

Admin AfterAcademy 12 Oct 2020

Reverse a Stack Using Recursion

Given a stack of integers st, write a program to reverse the stack using recursion. This problem will clear the concept of recursion.

Admin AfterAcademy 6 Oct 2020

Reverse First K Elements Of A Queue

Given an integer K and queue Q of integers. Write a program to reverse the order of the first K elements of the queue. The other elements will be in the same relative order.

Admin AfterAcademy 5 Oct 2020

Validate Stack Sequences

Given two sequences pushed and popped with distinct values, write a program to return true if and only if this could have been the result of a sequence of push and pop operations on an initially empty stack.

Admin AfterAcademy 5 Oct 2020

Surrounded regions

Given a 2-D matrix board where every element is either 'O' or 'X', write a program to replace 'O' with 'X' if surrounded by 'X'. It is a famous problem based on the concept of flood fill algorithms

Admin AfterAcademy 23 Sep 2020

Recursive Insertion Sort

Write a program for the recursive implementation of Insertion Sort. Insertion Sort is used to sort a given array. This problem will sharpen your recursion skills.

Admin AfterAcademy 23 Sep 2020

When to Convert a 2-D DP array to 1-D DP array And How?

In which situation 2 dimensional DP can be dropped to 1 dimension? Is there any principle or regular pattern? This is a very important question when it comes to optimization of DP arrays. Let's find out.

Admin AfterAcademy 16 Sep 2020

Find Nth Factorial

Write a program to find the factorial of a given number n. n is a non-negative integer. Factorial of a non-negative integer n is the multiplication of all integers smaller than or equal to n.

Admin AfterAcademy 14 Sep 2020

Sort List - Merge Sort

Sort a linked list using Merge Sort. This is a very famous interview problem that demonstrates the concept of recursion. This problem is quite similar to Merge Sort in Arrays.

Admin AfterAcademy 12 Sep 2020

Smallest Multiple With 0s and 1s

You are given an integer n, write a program to find the smallest multiple of n which consists of 0 and 1. The resultant number could be quite large so return it in the form of a string. This problem is a good example of graph-based problems.

Admin AfterAcademy 11 Sep 2020

Detect and Remove Loop In A Linked List

You are given the head of a linked list which probably contains a loop. If the list contains a loop, you need to find the last node of the list which points to one of its previous nodes to create a loop and make it point to NULL, thereby removing the loop.

Admin AfterAcademy 9 Sep 2020

Knight on chessboard

Given a square chessboard of A x B size, the position of Knight (C, D) and the position of a target (E, F) is given. Write a program to find out the minimum steps a Knight will take to reach the target position. This problem is a good example of BFS algorithm.

Admin AfterAcademy 7 Sep 2020

Largest Element In An Array

Given an array arr[] of size n , write a program to find the largest element in it. To find the largest element we can just traverse the array in one pass and find the largest element by maintaining a max variable.

Admin AfterAcademy 4 Sep 2020

Merge Two BST

Given two binary search trees with root nodes as tree1 and tree2 of size n and m, write a program to return an array of integers that contains all the elements of tree1 and tree2 in non-decreasing order. The expected time complexity is O(m+n).

Admin AfterAcademy 1 Sep 2020

Odd Even Linked List

Given a singly linked list, write a program to group all odd nodes together followed by the even nodes. You should try to do it in place and the program should run in O(n) time complexity.

Admin AfterAcademy 21 Aug 2020

Wave Array

You are given an unsorted array of integers(arr) of length n, write a program to sort it in wave form. The array elements in the resultant array must be such that arr[0] >= arr[1] <= arr[2] >= arr[3] <= arr[4] ... and so on. If there are multiple sorted orders in wave-form, return the one which is lexicographically smallest.

Admin AfterAcademy 20 Aug 2020

Merge Two Sorted Arrays

You are given two sorted arrays arr1[ ] and arr2[ ] of sizes m and n respectively. Write a program to merge them in such a way that the resultant array is sorted too.

Admin AfterAcademy 17 Aug 2020

Reverse Bits

Given a non-negative integer num, write a program to return the number obtained after reversing the bits of num.

Admin AfterAcademy 15 Aug 2020

Learn Debugging Node.js Applications

Most programming languages have their own debuggers supported by IDEs but Javascript is a scripting language, therefore, it doesn’t have an inbuilt full-featured debugger. We will discuss more on how to debug Node.js Applications.

Mrudul Sankhere 13 Aug 2020

Middle Of The Linked List

Given a non-empty, singly linked list with head node head, write a program to return a middle node of linked list. If there are even nodes, then there would be two middle nodes, we need to print second middle element.

Admin AfterAcademy 10 Aug 2020

Missing Number

Given an array arr[] consists of 0, 1, 2, 3, 4,.....n. But one of the numbers is missing in it. Write a program to find the number that is missing from the array.

Admin AfterAcademy 10 Aug 2020

Quick Sort

Sorting is a process of arranging items systematically. There are several ways to sort a list of items. A very useful sorting algorithm in all of the sorting algorithms is quicksort. Given an array of integers arr[], write a program to sort the array in ascending order using Quick Sort.

Admin AfterAcademy 10 Aug 2020

MVC Architecture in Web Applications

MVC architecture has become an extremely common and favoured design pattern for creating web applications. Let us explore more and learn why is it so famous and preferred in the world of web design.

Mrudul Sankhere 10 Aug 2020

Combinations

Given two integers n and k, Write a program to return all possible combinations of k numbers out of 1 2 3 ... n. Elements in a combination must be in a non-descending order. The combinations themselves must be sorted in ascending order, i.e., the combination with the smallest first element should be printed first.

Admin AfterAcademy 8 Aug 2020

Distribute Candy Problem

There are N children standing in a line with some rating value. You want to distribute a minimum number of candies to these children such that: Each child must have at least one candy. The children with higher ratings will have more candies than their neighbours. Write a program to calculate the minimum candies you must give.

Admin AfterAcademy 8 Aug 2020

What is Docker and what's so special about it?

Docker is a platform enabling the creation and use of a containerized app which increases application portability in an efficient way. Read the blog to know more.

Mrudul Sankhere 31 Jul 2020

How to use Docker?

Docker is an excellent platform that increases app portability in a very efficient manner. We will be discussing how to get started with Docker for beginners.

Mrudul Sankhere 31 Jul 2020

Deno vs Node

Deno is this new thing everyone is hyped about. Many say Node is redundant now. Is it? Well, No. But read this blog to find out more!

Mrudul Sankhere 29 Jul 2020

Express.js Middleware in Javascript

Middlewares are a set of functions in Javascript which are executed when a request is made to the web-server. We will be discussing the basics of middleware and how to code them in this blog.

Mrudul Sankhere 25 Jul 2020

Introduction to npm

npm is the standard package manager for Nodejs. This blog provides an introduction to npm and also how to publish your own package

Mrudul Sankhere 25 Jul 2020

Search in a 2-D Matrix

You are given a matrix arr of m x n size. Write a program to searches for a value k in arr. This arr has the following properties: - Integers in each row are sorted from left to right. - The first value of each row is greater than the last value of previous row. This is a basic optimization problem that will clear the concept of searching.

Admin AfterAcademy 18 Jul 2020

Binary Search

Given a sorted integer array arr[] of n elements and a target value k, write a program to search k in arr[]. The famous binary search algorithm is easy to implement and the best optimization technique for performing searching operations

Admin AfterAcademy 18 Jul 2020

Combination Sum

Given an array of integers arr[] and a target number k, write a program to find all unique combinations in arr[] such that the sum of all integers in the combination is equal to k. This famous backtracking problem has previously been asked in Adobe, Amazon, Facebook.

Admin AfterAcademy 18 Jul 2020

Generate Parentheses

Given n pairs of parentheses, write a program to generate all combinations of balanced parentheses. You have to return a string array containing all possible cases.

Admin AfterAcademy 18 Jul 2020

Max Product Subarray

You are given an array arr[] with n elements. Write a program to find the contiguous subarray which has the largest product. It's a typical optimization problem.

Admin AfterAcademy 18 Jul 2020

Maximal Square

You are given a 2D binary matrix arr[][] filled with 0's and 1's. The array contains a square of 1's. So, you need to find that square and return its area. The problem is a great example for practicing dynamic programming for technical interviews.

Admin AfterAcademy 18 Jul 2020

Interleaving Strings

Given three strings S1, S2 and S3, write a program which checks whether S3 is an interleaving of S1 and S2. The problem is a typical dynamic programming problem.

Admin AfterAcademy 18 Jul 2020

Minimum Number Of Jumps To Reach End

Given an array of non-negative integers arr[] of length n, where each element represents the max number of steps that can be made forward from that element. You are initially positioned at the first index of the array. Write a program to return the minimum number of jumps to reach the last index of the array.

Admin AfterAcademy 18 Jul 2020

Partition Equal Subset Sum

Given a non-empty array of positive integers arr[ ]. Write a program to find if the array can be partitioned into two subsets such that the sum of elements in both subsets is equal.

Admin AfterAcademy 18 Jul 2020

Recover Binary Search Tree-Interview Problem

Given a Binary Search Tree such that two of the nodes of this tree have been swapped by mistake. You need to write a program that will recover this BST while also maintaining its original structure

Admin AfterAcademy 16 Jun 2020

Largest Rectangle in a Histogram-Interview Problem

You are given an array of integers arr where each element represents the height of a bar in a histogram. Histogram is a graphical display of data using bars of different heights. The bars are placed in the exact same sequence as given in the array. You need to find the area of the largest rectangle found in the given histogram.

Admin AfterAcademy 16 Jun 2020

Word Ladder Problem

This is a typical graph problem that needs a proper understanding of building a graph and traversing on it using a breadth-first search.

Admin AfterAcademy 16 Jun 2020

Max Points On The Straight Line

Given N point on a 2D plane as pair of (x, y) coordinates, Write a program to find the maximum number of point which lie on the same line. This is a famous mathemtical problem and clears the concepts of problem related with XY planes.

Admin AfterAcademy 16 Jun 2020

Convert A Min Heap to Max Heap

Given array representation of min Heap, write a program to convert it to max Heap. This problem will clear the concepts of the heap and priority queue which is a very important concept of data structures.

Admin AfterAcademy 11 Jun 2020

Valid Anagram

Write a program to check whether the two strings are an anagram of each other or not. Like, "s" is an anagram of "t" if the characters of "s" can be rearranged to form "t". This simple problem will let you understand the concepts of string manipulation.

Admin AfterAcademy 11 Jun 2020

Minimum Spanning Tree

In this blog, we will learn about Minimum Spanning Tree. We will also discuss two algorithms which is used to find a minimum spanning tree.

Admin AfterAcademy 8 Jun 2020

Reverse An Array

Reverse a given array in-place. This question uses the concept of swapping.

Admin AfterAcademy 8 Jun 2020

Merge two Binary Trees - Interview Problem

This is an interview problem asked in companies like Amazon, Microsoft. The problem is to merge two binary trees. The overlapping nodes are replaced by the sum of corresponding nodes. We are discussing two ways of solving this.

Admin AfterAcademy 6 Jun 2020

Minimum Absolute Difference in a BST-Interview Problem

This is an interview problem asked in Google technical interview. Given a BST(Binary Search Tree) with non-negative values, write a program to find the minimum absolute difference between values of any two nodes.

Admin AfterAcademy 6 Jun 2020

Find the Closest Palindrome

Given an integer k, write a program to find the closest integer (not including itself), which is a palindrome.

Admin AfterAcademy 6 Jun 2020

Sliding Window Maximum

You are given an integer array arr of size n. Assume a sliding window of size k starting from index 0. In each iteration, the sliding window moves to the right by one position till n-k. Write a program to return an array representing the maximum number in all sliding windows.

Admin AfterAcademy 2 Jun 2020

Applications of Hash Table

Hashing is a way to store data into some data structure (generally Hash Table is used) in such a way that the basic operations on that data i.e. the insertion, deletion, and searching can be performed in O(1) time. It is one of the important concepts that every programmer and developer should know. In this blog, we will know some of the applications on Hash Table.

Admin AfterAcademy 2 Jun 2020

Matrix Chain Multiplication

Given a chain <M1, M2...Mn> of n two-dimensional matrices, write a program to fully parenthesize the product M1×M2×⋯×Mn in a way that minimizes the number of multiplications. It's a famous dynamic programming problem.

Admin AfterAcademy 2 Jun 2020

Longest Arithmetic Progression

The problem requires knowledge of dynamic programming and Arithmetic progression. Given a set of integers in an array A[] of size n, write a program to find the length of the longest arithmetic subsequence in A.

Admin AfterAcademy 2 Jun 2020

Gas Station Problem

There are N gas stations along a circular route, where the amount of gas at station i is arr[i]. You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from station i to its next station (i+1). At the beginning of the journey, the tank is empty at one of the gas stations. Return the minimum starting gas station's index if you can travel around the circuit once, otherwise return -1.

Admin AfterAcademy 2 Jun 2020

All Nodes Distance K in Binary Tree

Find all nodes at a distance k from a target node. This problem requires the knowledge of tree data structure. Recursion and tree traversals would be the base of the solution for this problem.

Admin AfterAcademy 2 Jun 2020

What is a Phantom deadlock?

In this blog, we will learn about a specific deadlock, i.e., Phantom deadlock, and will also see some examples of its occurrence.

Admin AfterAcademy 2 Jun 2020

What is Banker’s algorithm?

In this blog, we will see one of the deadlock avoidance methods i.e. Banker's Algorithm. In this algorithm, we will discuss that if we are given the number of resources available and the number of resources required by the process then we can tell that if the system will go in deadlock or not. We will understand this concept with the help of an example.

Admin AfterAcademy 2 Jun 2020

Getting started with Express.js

In this tutorial, we are going to learn about Express.js, why it is used, what all features it offers, and how it is used in the development environment. This tutorial will provide you with the most basic and important knowledge that is required in order to use Express in web application servers.

Akshay Upadhyay 28 May 2020

From JavaScript to TypeScript

In this tutorial, we are going to learn about some of the features that TypeScript provides which may or may not be present in JavaScript and are important to know if you are migrating from JavaScript to TypeScript.

Akshay Upadhyay 15 May 2020

NPM vs Yarn

npm and Yarn are two very popular and highly used package managers and we discuss on the comparisons between the two in this blog

Mrudul Sankhere 11 May 2020

Binary Tree Zig Zag Level Order Traversal

Given a binary tree, return the zigzag level order traversal of its nodes' values. (i.e, from left to right, then right to left for the next level and alternate between). The problem is a typical Interview problem based on Tree Traversal

Admin AfterAcademy 4 May 2020

Topological Sorting

In this blog, we will discuss Topological sort in a Directed Acyclic Graph. We will discuss what is the Topological Sort, how can we find Topological Ordering, Illustration using a Directed Acyclic Graph, its pseudo-code, and its applications.

Admin AfterAcademy 1 May 2020

Optimal Substructure and Overlapping Subproblems

In this blog, we will understand the optimal substructure and overlapping subproblems property. We will also discuss how the problems having these two properties can be solved using Dynamic programming.

Admin AfterAcademy 1 May 2020

Merge Overlapping Intervals

You will be given a set of intervals in the form of a 2-D array, write a program to merge all the overlapping intervals, and return the array. This problem will clear the concept of intervals and Graph

Admin AfterAcademy 1 May 2020

Path Sum In Binary Tree

Given a binary tree and a sum, write a program to determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum.Its an easy problem based on Binary tree traversal and a famous interview question

Admin AfterAcademy 1 May 2020

Maximum Product Of Three Numbers

write a program to find three numbers whose product is maximum and output the maximum product. This is a basic mathematical problem and requires logical skill to solve.

Admin AfterAcademy 1 May 2020

Check If Two Arrays Are Equal Or Not

Given two given arrays of equal length, Check if given arrays are equal or not. This is a tricky interview problem as, at first, this looks like problem-related to combinatorics but could be solved quickly upon thinking.

Admin AfterAcademy 1 May 2020

Dijkstra’s Algorithm

In this blog, we will discuss Dijkstra's Algorithm. We will discuss what is the Dijkstra's Algorithm, how can we find the shortest path from source to other vertices using Dijkstra's Algorithm in Graph, Illustration using an example, its pseudo-code.

Admin AfterAcademy 1 May 2020

Min Stack Problem

This is an interview problem asked in companies like Amazon, Microsoft, Yahoo and Adobe. The problem is to design a stack that will support push(), pop(), top() and getMin() operation in constant time. We will be discussing two different ways to approach this problem.

Admin AfterAcademy 1 May 2020

Search For A Range In Sorted Array

Given a sorted array A[] with possibly duplicate elements, write a program to find indexes of first and last occurrences of an element k in the given array. This question will clear your concept of Binary Search

Admin AfterAcademy 1 May 2020

What is a Thread in OS and what are the differences between a Process and a Thread?

In this blog, we will learn about threads and its two types i.e. user-level thread and kernel-level thread. We will also see what are the advantages of using threads in the OS. Finally, we will learn about the difference between process and thread

Admin AfterAcademy 1 May 2020

What is the concept of Multithreading in OS and what are its benefits?

In this blog, we will learn about various multithreading models like one-to-one, many-to-one, and many-to-many. We will compare these models and analyze which one is the best. Further, we will also see the benefits of multithreading.

Admin AfterAcademy 1 May 2020

What is the difference between SQL and SQL server?

In this blog, we will learn about the various differences between SQL and SQL server based on some points.

Admin AfterAcademy 1 May 2020

Inversion Count in an Array-Interview Problem

Given an array of integers A[ ], if i < j and A[i] > A[j] then the pair (i, j) is called the inversion of an array A[ ]. You need to write a program to find the total counts of inversion in an array A[ ]. The inversion count of an array suggests how close the array is from being sorted. This problem has been asked in Amazon and Google's interview.

Admin AfterAcademy 1 May 2020

Migrating from Promise chains to Async/Await

Introduces Async/Await and compare it with Promises. We shall discuss migrating your from Promise Chains to Async/Await .

Mrudul Sankhere 30 Apr 2020

What is Load Balancing? How does it work?

In this blog, we will learn the concept of Load Balancing. We will see why load balancing is important while we scale our product and how can we reduce the load on a particular server.

Sumit Mishra 29 Apr 2020

What is Pattern matching in SQL and how it is done?

In this blog, we will see what is pattern matching in SQL. We will also learn to perform pattern matching with examples.

Admin AfterAcademy 22 Apr 2020

What are Paging and Segmentation?

In this blog, we will learn about two non-contiguous memory allocation technique i.e. paging and segmentation. We will also learn how the logical address is converted into the physical address in both the techniques. Further, we will analyze the advantages and disadvantages of each technique.

Admin AfterAcademy 22 Apr 2020

What are demand-paging and pre-paging?

In this blog, we will learn how pages are brought into the main memory in virtual memory systems. We will see two ways of doing this i.e. demand paging and pre-paging.

Admin AfterAcademy 22 Apr 2020

Authentication vs Authorization

Authentication and Authorization are closely related terms and we shall discuss the difference between the two in this blog.

Admin AfterAcademy 12 Apr 2020

TypeScript Tutorial For Beginners

In this tutorial, We are going to learn about the basics of Typescript. If you are having any doubts, whether to use typescript over javascript or Do I really need it? then this article is for you. Learn the concepts behind Typescript and its necessity in today's world.

Admin AfterAcademy 9 Apr 2020

How to become Developer Student Clubs Leads?

If you want to share your knowledge with others and want to learn back from them, then you must be in some community. Developer Student Clubs is one such community by Google Developers. Learn how to become a Developer Student Clubs lead at your campus.

Admin AfterAcademy 8 Apr 2020

Heap Building and Heap Sort

Heap is a very useful data structure that every programmer should know well. The heap data structure is used in Heap Sort, Priority Queues. The understanding of heaps helps us to know about memory management. In this blog, we will discuss the various about Heap Building and Heap Sort.

Admin AfterAcademy 7 Apr 2020

Longest Increasing Subsequence - Interview Problem

You are given an array A with N elements. You need to find the longest increasing subsequence in the array.

Admin AfterAcademy 7 Apr 2020

Longest Common Prefix

Find the LCP. This is a very famous interview problem and demonstrates the use of various approaches and techniques to solve.

Admin AfterAcademy 7 Apr 2020

What is Belady’s Anomaly?

In this blog, we will learn what is Belady's anomaly and we will analyze how increasing the frame number leads to Beladys Anomaly in FIFO.

Admin AfterAcademy 7 Apr 2020

Remove Nth Node From End of List

You are given a linked list, write a program to remove the nth node from the end of the list and return the head. This problem has been previously asked in Google and Amazon and requires the understanding of the linked list to solve it.

Admin AfterAcademy 6 Apr 2020

Sort A Stack Using Another Stack

Given a stack, you have to sort it in ascending order. You can use another stack if you need auxiliary space. The problem is asked in Google, Microsoft and Amazon and requires knowledge of Stack and recursion to solve it.

Admin AfterAcademy 6 Apr 2020

Edit Distance

Write an algorithm to find the minimum number of operations required to convert string S1 into S2.

Admin AfterAcademy 6 Apr 2020

Median in a Row-wise Sorted Matrix-Interview Problem

The problem is to find the median in a row-wise sorted matrix. This is an interview problem asked in companies like Amazon. There is a further constraints on extra space. We have discussed two possible solutions.

Admin AfterAcademy 6 Apr 2020

What are UNION, MINUS, and INTERSECT commands in DBMS?

In this blog, we will learn what are the UNION, MINUS, and INTERSECT commands in SQL. We will also see their application with examples.

Admin AfterAcademy 6 Apr 2020

What is Cross-Join in DBMS?

In this blog, we will learn how to cross-join two tables in DBMS, and what are the benefits of doing it with example.

Admin AfterAcademy 6 Apr 2020

What is the difference between logical and physical address wrt Operating System?

In this blog, we will learn about the two types of addresses that are used for memory in the operating system. Further, we will discuss the difference among these types of memories i.e. logical memory and physical memory.

Admin AfterAcademy 30 Mar 2020

What is Fragmentation and what are its types?

In this blog, we will learn about the fragmentation problem that occurs during memory allocation. We will also study the types of fragmentation i.e. internal fragmentation and external fragmentation.

Admin AfterAcademy 30 Mar 2020

First Unique Character In A String

Given a string S, write a program to find the first non-repeating character in it and return its index. The problem needs to be solved in O(n) and needs the knowledge of a hash map to solve.

Admin AfterAcademy 30 Mar 2020

Triplet With Zero Sum

Given an array arr[ ] of n integers, are there elements x, y, z in arr such that x + y + z = 0? Find all unique triplets in the array which gives the sum of zero. The problem is asked in many interviews and required do be solved in O(n^2) with constant space.

Admin AfterAcademy 30 Mar 2020

Sudoku Solver

This problem is based on the famous sudoku puzzle. A sudoku board of 9x9 is given and you are expected to fill it correctly. The problem requires knowledge of Backtracking. This is a typical backtracking problem.

Admin AfterAcademy 30 Mar 2020

Find an Element In a Bitonic Array

Given a bitonic sequence of n distinct elements, write a program to search a given element k in the bitonic sequence. Bitonic Sequence is a sequence of numbers that is first strictly increasing then after a point strictly decreasing.

Admin AfterAcademy 23 Mar 2020

What is the difference between OLTP and OLAP?

In this blog, we will first discuss what is Online Transaction Processing and Online Analytical Processing and then learn the difference among them.

Admin AfterAcademy 21 Mar 2020

What is Join in DBMS and what are its types?

In this blog, we will learn how to join two tables in DBMS. We will also learn about the various types of joins, mainly the inner and the outer join.

Admin AfterAcademy 21 Mar 2020

What is Data independency?

In this blog, we will learn about data independence and how it helps in doing modification in the database. Further, we will discuss its two types on the basis of levels of abstraction in DBMS.

Admin AfterAcademy 21 Mar 2020

What is a Stored Procedure in DBMS?

In this blog, we will learn what is a stored procedure in DBMS, and how it is executed depending on the number of parameters passed.

Admin AfterAcademy 21 Mar 2020

What is Self-Join in DBMS?

In this blog, we will learn how to join a table by itself, and what are the benefits of self-join with example.

Admin AfterAcademy 21 Mar 2020

What is a Deadlock in DBMS and what are the deadlock avoidance, detection, and prevention techniques?

In this blog, we will learn what is a deadlock situation, what are various deadlock handling techniques like deadlock prevention, deadlock avoidance, deadlock detection, and deadlock ignorance.

Admin AfterAcademy 21 Mar 2020

How to prepare for the Coding Interview?

Coding interview preparation plan and the topics that you should cover before your interview. It will help you to get a basic plan structure that you should manage and keep your schedule accordingly.

Admin AfterAcademy 18 Mar 2020

Implement Queue Using Stack-Interview Problem

This is an interview problem asked in companies like Microsoft, Amazon, Adobe, Flipkart, etc. Here, we need to implement Queue data structure using another data structure Stack. This problem is meant for testing the data structure knowledge.

Admin AfterAcademy 16 Mar 2020

What is a transaction? What are ACID properties?

In this blog, we will learn what is a transaction, what are the transaction states. We will also learn about the ACID properties that are followed by all the transactions taking place in the database.

Admin AfterAcademy 16 Mar 2020

Difference between Trigger and Stored procedure in DBMS

In this blog, we will learn how triggers are different from stored procedures.

Admin AfterAcademy 16 Mar 2020

File Upload with Multer in Node.js and Express

In this tutorial, we are going to learn how to upload files on the server with the help of Multer and Express in Node.js. The goal is to make you comfortable in building apps that can easily handle any file uploads. At the end of this blog, you will be able to integrate the file uploads in your own apps.

Admin AfterAcademy 9 Mar 2020

RESTful API Using Node and Express

In this tutorial, we will learn to build the RESTful API using Node and Express. The goal is to make you comfortable in building your RESTful API with Node.js and Express. At the end of this blog, you will be able to build your REST APIs using Node.js and Express.

Admin AfterAcademy 6 Mar 2020

Everything you need to know about GSoC

In this blog, we will get to know everything about GSoC i.e. how to apply, when to apply, what are the benefits of GSoC, etc.

Admin AfterAcademy 5 Mar 2020

Operations on Heaps

Heap is a very useful data structure that every programmer should know well. The heap data structure is used in Heap Sort, Priority Queues. The understanding of heaps helps us to know about memory management. In this blog, we will discuss various operations that are done on heaps.

Admin AfterAcademy 4 Mar 2020

What is a Trigger in DBMS?

In this blog, we will learn why a trigger is needed, what is it, what are the advantages and disadvantages of using a trigger.

Admin AfterAcademy 4 Mar 2020

What is Data Encapsulation and de-encapsulation in networking?

In this blog, we will learn what is data encapsulation in the computer network. We will also see the encapsulation and de-encapsulation process in the OSI and TCP/IP models.

Admin AfterAcademy 4 Mar 2020

What happens when you use cables longer than the prescribed length in a network?

In this blog, we will see what happens when we use a cable longer than the prescribed length in the network. We will also see whether it is favorable for the network or not.

Admin AfterAcademy 4 Mar 2020

What is View in SQL?

In this blog, we will learn about the view or virtual tables in SQL. We will also discuss various operations we can perform on views in SQL.

Admin AfterAcademy 3 Mar 2020

Difference between a Domain and a Workgroup

In this blog, we will learn what is a domain and a workgroup. We will also see the application and the differences between the two.

Admin AfterAcademy 3 Mar 2020

Rain Water Trapping

Given n non-negative integers representing an elevation map where the width of each bar is 1. Write a program to compute how much water it is able to trap after raining.

Admin AfterAcademy 3 Mar 2020

Lowest Common Ancestor of a Binary Search Tree

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. This is a very famous interview problem and previously asked in Microsoft and Amazon.

Admin AfterAcademy 3 Mar 2020

Lowest Common Ancestor of a Binary Tree

Given a binary tree, write a program to find the lowest common ancestor (LCA) of two given nodes in the tree. The question is asked previously in Amazon, Facebook, Adobe and requires an understanding of tree data structure.

Admin AfterAcademy 3 Mar 2020

Find Diameter of Binary Tree

Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.

Admin AfterAcademy 3 Mar 2020

Median of the Two Sorted Array of Same Size

There are two sorted arrays nums1 and nums2 of size n. Find the median of the two sorted arrays.

Admin AfterAcademy 29 Feb 2020

Dynamic Programming vs Greedy Algorithms

These are two very useful and commonly used algorithmic paradigms for optimization and we shall compare the two in this blog and see when to use which approach.

Admin AfterAcademy 29 Feb 2020

Check for Balanced Parentheses in an Expression

This is a famous interview problem asked in companies like Amazon, Microsoft. Here the basic idea is to think of the data structure which can easily solve this problem.

Admin AfterAcademy 29 Feb 2020

Find the Square Root of a given Integer-Interview Problem

Given an integer, your task is to find the square root of the integer. For an integer x to be the square root of the given integer N, x*x must be equal to N. This is an interview problem asked in companies like Amazon, Microsoft and Facebook.

Admin AfterAcademy 29 Feb 2020

What is a localhost?

In this blog, we will learn what is localhost. We will also learn various applications of the localhost.

Admin AfterAcademy 29 Feb 2020

What are the Page Replacement Algorithms?

In this blog, we will learn about various Page Replacement Algorithms that are used in memory management in OS. We will learn about FIFO, LRU, and Optimal page replacement.

Admin AfterAcademy 29 Feb 2020

What are the classes of IPV4? How to identify IP class from a given IP address?

In this blog, we will learn what are the various types of classes in IPv4 and how we can differentiate among the classes on the basis of the number of bits present the network ID and the host ID of these classes.

Admin AfterAcademy 29 Feb 2020

What is a Subnet mask?

In this blog, we will learn why we need a subnet mask, what is a subnet mask and how a subnet mask helps in identifying the network of the IP address.

Admin AfterAcademy 29 Feb 2020

What can be done to fix signal attenuation problems?

In this blog, we will learn what is attenuation, what are the causes of attenuation and finally we saw what can be done to fix the signal attenuation problem.

Admin AfterAcademy 29 Feb 2020

What are ICMP and IGMP protocols?

In this blog, we will learn about what is ICMP protocols and various messages involved with this protocol. We will also discuss the IGMP protocol of the TCP/IP and various versions of this protocol.

Admin AfterAcademy 29 Feb 2020

What is the maximum segment length of a 100Base-FX network?

In this blog, we will learn what are the pieces of information hidden in the name of the network like 100BaseFX. We will learn about 100baseFX and what is its maximum segment length.

Admin AfterAcademy 29 Feb 2020

What is DNS?

In this blog, we will learn about the Domain Name System(DNS) and its need. We'll also see the working and various types of DNS.

Admin AfterAcademy 29 Feb 2020

What is the concept of Subnetting and Supernetting?

In this blog, we will learn about the concept of subnetting, why it is done and how it is done. Further, we will learn about supernetting, why it is done and how it is done. We will also see how the supernet mask of any network is calculated.

Admin AfterAcademy 29 Feb 2020

Difference between ipconfig and ifconfig?

In this blog, we will learn what is ipconfig and ifconfig. We'll also see the application and differences between the two.

Admin AfterAcademy 29 Feb 2020

What is the difference between HAVING and WHERE clause?

In this blog, we will learn how WHERE and HAVING clause are used and then see what are the main differences between the WHERE clause and HAVING clause.

Admin AfterAcademy 29 Feb 2020

What is Pipelining?

In this blog, we will learn what is pipelining. We will also see the application and features of using pipelining in computer networks.

Admin AfterAcademy 29 Feb 2020

Difference between IPv4 and IPv6

In this blog, we will discuss IPv4 and IPv6 versions of IP address. We will also discuss in details about their packet formats and finally see the differences among them.

Admin AfterAcademy 29 Feb 2020

What is an IP address?

In this blog, we will learn what is an Ip address and what are the various versions of IP addresses being used. We will also discuss what are the types of IP addresses depending upon how they are assigned to any system.

Admin AfterAcademy 29 Feb 2020

What is a Network Operating System?

In this blog, we'll learn about the Network Operating System and its various features. We'll also see the types of Network Operating System, their advantages, and disadvantages.

Admin AfterAcademy 29 Feb 2020

Mastering Mongoose for MongoDB and Nodejs

In this blog, we are going to master the concepts of Mongoose, MongoDB with the help of node.js.

Admin AfterAcademy 25 Feb 2020

What is the difference between MAC address and IP address?

In this blog, we will first learn about the MAC and IP addresses in brief. And then, we'll see the dissimilarities between the two.

Admin AfterAcademy 18 Feb 2020

What is the difference between TCP and UDP?

In this blog, we will first briefly understand TCP and UDP, and then we will see the dissimilarities between them. We'll also see which one is better to implement in which case.

Admin AfterAcademy 18 Feb 2020

Difference between a Firewall and Antivirus

In this blog, we will learn about what is an antivirus and how does it work. We will then discuss the dissimilarities between the firewall and antivirus.

Admin AfterAcademy 18 Feb 2020

What are Greedy Algorithms?

This blog deals with the introduction of greedy algorithms for beginners and enthusiasts.

Admin AfterAcademy 18 Feb 2020

Merge Sort

Merge sort is a divide-and-conquer algorithm based on the idea of breaking down a list into several sub-lists until each sublist consists of a single element and merging those sublists in a manner that results into a sorted list.

Admin AfterAcademy 18 Feb 2020

Priority Queues

Priority Queues are similar to queues where we insert an element from the back and remove an element from the front, but with one difference that the logical order of elements in the priority queue depends on the priority of the elements. In this blog, we will discuss the priority queues, its properties, its various implementations, and its applications. We will also analyze and compare the various implementations of the Priority Queue.

Admin AfterAcademy 18 Feb 2020

Introduction to Heaps in Data Structures

Heap is a very useful data structure that every programmer should know well. The heap data structure is used in Heap Sort, Priority Queues. The understanding of heaps helps us to know about memory management. In this blog, we will discuss the structure, properties, and array implementation of heaps.

Admin AfterAcademy 18 Feb 2020

Remove Duplicates From a Sorted Linked List-Interview Problem

This is an interview problem asked by companies like Myntra, Visa, Oracle, Adobe, etc. The problem is to remove the duplicate nodes from the given Linked List so that only unique nodes(with unique data values) are present.

Admin AfterAcademy 18 Feb 2020

Steps Of Problem Solving During Technical Interview

In this blog, we will discuss about the steps of problem solving during the technical interview and how to cross the first hurdle for a programmer to get into the software industry and land their dream job.

Admin AfterAcademy 11 Feb 2020

Which model is better, OSI or TCP/IP?

In this blog, we have described the similarities and dissimilarities between the OSI and TCP/IP models. We've also tried to tell which model is better for which scenario.

Admin AfterAcademy 11 Feb 2020

What is Backtracking?

This blog discusses the concept of Exhaustive Search and Backtracking.

Admin AfterAcademy 11 Feb 2020

Binary Search Tree: Introduction, Operations and Applications

Binary Search Trees is one of the most important variation of binary tree and is extremely useful in practical applications. The blog discusses the operations and applications of this powerful data structure

Admin AfterAcademy 11 Feb 2020

What are the operations implemented in tree and what are its applications?

Tree Data Structure supports various operations such as insertion, deletion and searching of elements along with few others. This blogs discussed those operations along with explaining its applications.

Admin AfterAcademy 11 Feb 2020

Rotate Matrix

Given a square matrix, turn it by 90 degrees in the clockwise direction.

Admin AfterAcademy 11 Feb 2020

Types of Linked List and Operation on Linked List

In this blog, we will discuss the types of linked list and basic operations that can be performed on a linked list.

Admin AfterAcademy 10 Feb 2020

Merge K Sorted Lists

Merge k sorted linked lists and return it as one sorted list.

Admin AfterAcademy 10 Feb 2020

Check if the Singly Linked List is a Palindrome-Interview Problem

Given a Linked List, your task is to find whether the given singly linked list is a palindrome or not. This is an interview problem asked in many companies like Amazon, Microsoft, Adobe, Flipkart and other big companies.

Admin AfterAcademy 10 Feb 2020

Graph Traversal: Breadth First Search

In this blog, we will learn Breadth First Search that is used for Graph Traversal i.e. the Breadth First Search is used to traverse each and every node of a graph. So, let's learn together.

Admin AfterAcademy 10 Feb 2020

Graph Traversal: Depth First Search

In this blog, we will learn Depth First Search that is used for Graph Traversal i.e. the Depth First Search is used to traverse each and every node of a graph. So, let's learn together.

Admin AfterAcademy 10 Feb 2020

What are Scalar functions?

In this blog, we will learn about some of the Scalar functions that are used in SQL.

Admin AfterAcademy 10 Feb 2020

What are aggregate functions?

In this blog, we will learn about some of the aggregate functions that are used in SQL. These aggregate functions take more than one value and return one value as a result.

Admin AfterAcademy 10 Feb 2020

What is the difference between TRUNCATE, DELETE and DROP statements?

In this blog, we will see the difference between the TRUNCATE, DELETE, and DROP statements that are used in MySQL.

Admin AfterAcademy 10 Feb 2020

What are the various types of constraints in SQL?

In this blog, we will learn various types of constraints that can be applied on a table. These constraints can be used to validate the data present in the table. We will learn about NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK, and DEFAULT

Admin AfterAcademy 10 Feb 2020

Linked List and its Properties

In this blog, we will discuss about the linear data structure called Linked Lists. We will discuss its properties, advantages, and disadvantages. So, let's get started

Admin AfterAcademy 10 Feb 2020

Divide & Conquer vs Dynamic Programming

Divide and Conquer and Dynamic Programming are two most used problem-solving skills in Data Structures. In this blog, we will see the similarities and difference between Dynamic Programming and Divide-and-Conquer approaches.

Admin AfterAcademy 10 Feb 2020

Greatest Common Divisor-Interview Problem

This is a mathematical problem asked in interviews of Google like companies. For solving such problems you need to have some math skills and also some idea of algorithms like Euclid's GCD algorithm.

Admin AfterAcademy 10 Feb 2020

What is RIP(Routing Information Protocol)?

In this blog, we will learn about what is RIP and how does it work. We will also discuss what are versions of RIP and various RIP timers. In last will see the advantages and disadvantages of this protocol.

Admin AfterAcademy 10 Feb 2020

What do you mean by a Firewall?

In this blog, we will what is a firewall, why is it important, how it works, what are its types, and how it protects our network from threats from the internet.

Admin AfterAcademy 10 Feb 2020

What is the TCP/IP model and how it works?

In this blog, we will mainly learn about the TCP/IP model and its working in detail. We'll focus on the features and working of each layer of the TCP/IP model.

Admin AfterAcademy 10 Feb 2020

What is a TCP 3-way handshake process?

In this blog, we will learn about the TCP protocol and the 3-way handshake process involved in it.

Admin AfterAcademy 10 Feb 2020

What are Proxy Servers and how do they protect computer networks?

In this blog, we will learn what is a proxy server, how does it work and what are the various types of proxy servers. We will also see why we should use a proxy server and what are the risks associated with it.

Admin AfterAcademy 10 Feb 2020

Minimum Cost Path - Interview Problem

This is a famous interview problem based on dynamic Programming. This question has been asked in big companies like Amazon. Here we need to find the path between the given source and destination that gives the minimum cost.

Admin AfterAcademy 10 Feb 2020

Remove Duplicates in a Sorted Array-Interview Problem

This is an interview problem asked in companies like Google, Microsoft, Amazon. The problem is to remove duplicates from a sorted array or list.

Admin AfterAcademy 7 Feb 2020

Array vs Linked List

Array and Linked List are the two most used data structures. It's really important to understand and compare the advantages and disadvantages of both array and linked list. In this blog, we will compare these two linear data structures. So let's get started.

Admin AfterAcademy 7 Feb 2020

Calculate power function

Calculate the value of x^n.

Admin AfterAcademy 7 Feb 2020

What is the OSI model and how it works?

In this blog, we will mainly learn about the OSI model and its working in detail. We'll focus on the features and working of each layer of the OSI model.

Admin AfterAcademy 7 Feb 2020

What is ARP and how does it work?

In this blog, we will learn what is Address Resolution Protocol and how it helps in communication between two devices. We will also discuss what are the problems that can arise while using this protocol and see sample examples of ARP packets which are captured.

Admin AfterAcademy 7 Feb 2020

What is DHCP and how does it work?

In this blog, we will learn what is DHCP, what are various entities related to DHCP and how does it work. We will also discuss how IP configurations are dynamically done.

Admin AfterAcademy 6 Feb 2020

What happens when you type a URL in the web browser?

In this blog, we will learn what happens when type any URL in the address box of a web browser. We will see step by step, how the HTTP request is sent and the HTTP response is received.

Admin AfterAcademy 6 Feb 2020

Binary Search Tree vs Hash Table

In this blog, we will see the difference between a binary search tree and a hash table. We will see which data structure should be used when to solve our problems.

Admin AfterAcademy 6 Feb 2020

Introduction to Graph in Programming

In this blog, we will learn about the Graph data structure that is used to store data in the form of vertices and edges. We will also see some of the properties, types, representation of graph.

Admin AfterAcademy 6 Feb 2020

Introduction to Arrays

The idea of this blog is to discuss the famous data structure called Array. An Array is one of the important data structures that are asked in the interviews. So, we will learn about arrays and we will also discuss about the idea of the dynamic array and its amortized analysis. So let's get started.

Admin AfterAcademy 6 Feb 2020

What is a NIC(Network Interface Card)?

In this blog, we will learn what is a Network Interface Card, what are its types, what are the various factors that determine the speed of the internet along with the Network Interface Cards speed.

Admin AfterAcademy 6 Feb 2020

What is FTP and how does an FTP work?

In this blog, we will learn what is an FTP protocol, how does it works, what are various modes in which it works, what are the advantages and disadvantages of using it.

Admin AfterAcademy 6 Feb 2020

What is Piggybacking?

In this blog, we will learn why piggybacking is used and how it helps in increasing the efficiency of data transmission. We will also discuss the advantages and disadvantages of piggybacking.

Admin AfterAcademy 4 Feb 2020

What is Stop and Wait protocol?

In this blog, we will learn one of the flow control method i.e Stop and Wait Protocol. We will discuss various situations that can occur while transmitting the data. We will also mathematically derive the efficiency and the throughput of this protocol.

Admin AfterAcademy 4 Feb 2020

What is the difference between Unicasting, Anycasting, Multicasting, and Broadcasting?

In this blog, we will learn about the various network traffic types, that are - Unicasting, Anycasting, Multicasting, and Broadcasting. We'll also see their advantages and disadvantages along with their differences.

Admin AfterAcademy 4 Feb 2020

What is Error-Control in networking?

In this blog, we will discuss what is an error, what are its types, how to detect these errors. We will also know about are various error control techniques like stop and wait ARQ, Go-Back-N ARQ, and Selective Repeat ARQ.

Admin AfterAcademy 4 Feb 2020

What are various Message switching techniques?

In this blog, we will learn about various messaging techniques like circuit switching, packet switching, and message switching. We will also discuss their applications in the real world.

Admin AfterAcademy 4 Feb 2020

Introduction To Sorting Algorithms - Selection and Insertion sort

Sorting is a famous problem solving approach during the interview. In this blog, we are going to discuss about the insertion and selection sort algorithm.

Admin AfterAcademy 27 Jan 2020

What are the different types of SQL commands?

In this blog, we will learn about various SQL commands such as DDL, DML, TCL, DCL.

Admin AfterAcademy 23 Jan 2020

What are Gateways?

In this blog, we'll learn about gateways, their working, features, advantages and disadvantages.

Admin AfterAcademy 23 Jan 2020

Reverse a Linked List

The problem is about reversing a Linked List. We are given the head node of the Linked List and we have to return the reversed Linked List's head. This is an interview problem asked in companies like Microsoft, Amazon and Adobe.

Admin AfterAcademy 22 Jan 2020

Getting started with Competitive Programming

In this blog, we will see how to get started with Competitive Programming. Competitive Programming is very important because in every interview you will be asked to write some code. So, let's learn together.

Admin AfterAcademy 22 Jan 2020

What are Routers, Hubs, Switches, Bridges?

In this blog, we'll learn about the networking devices such as Routers, Hubs, Switches, and Bridges. We'll also learn about the functionality, advantages, and disadvantages of these devices.

Admin AfterAcademy 22 Jan 2020