Extramarks Education System Engineer Interview Questions and Answers

Round duration - 60 Minutes
Round difficulty - Easy

It was an coding round

Q1. 
The Skyline Problem
Compute the skyline of given rectangular buildings in a 2D city, eliminating hidden lines and forming the outer contour of the silhouette when viewed from a distance. Each building is ...read more
Ans. 
Compute the skyline of given rectangular buildings in a 2D city, eliminating hidden lines and forming the outer contour of the silhouette.
• Iterate through the buildings and create a list of critical points (x, y) where the height changes.

• Sort the critical points based on x-coordinate and process them to form the skyline.

• Merge consecutive horizontal segments of equal height into one to ensure no duplicates.

• Return the fin...read more
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Q2. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Ans. 
Find all possible paths for a rat in a maze from source to destination.
• Use backtracking to explore all possible paths in the maze.

• Keep track of visited cells to avoid revisiting them.

• Recursively try moving in all directions (up, down, left, right) until reaching the destination.

• Return a list of strings representing valid paths sorted in alphabetical order.
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Round duration - 30 Minutes
Round difficulty - Easy

It was an HR round with some general questions. it was just for formality.

Q1. Difference between var, let, const.
Ans. 
var, let, and const are all used to declare variables in JavaScript, but they have different scoping rules and behaviors.
• var has function scope and can be redeclared and reassigned

• let has block scope and can be reassigned but not redeclared

• const has block scope and cannot be reassigned or redeclared

• Use const for values that won't change, let for values that will, and avoid var
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Q2. Explain CSS box model. Do padding and margin apply to inline elements?
Ans. 
CSS box model defines the layout of elements on a webpage. Padding and margin can apply to block-level elements but not to inline elements.
• CSS box model consists of content, padding, border, and margin around an element.

• Padding adds space inside the border of an element.

• Margin adds space outside the border of an element.

• Padding and margin can apply to block-level elements like <div> but not to inline elements lik
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Q3. Difference between arrow functions and regular ones.
Ans. 
Arrow functions are shorter syntax for writing function expressions.
• Arrow functions do not have their own 'this' keyword.

• Arrow functions cannot be used as constructors.

• Arrow functions do not have the 'arguments' object.

• Arrow functions are more concise and easier to read.

• Regular functions are better for methods and constructors.
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Q4. How does JavaScript asynchronous model work
Ans. 
JavaScript asynchronous model allows non-blocking code execution by using callbacks and promises.
• JavaScript uses an event loop to handle asynchronous operations.

• Callbacks are functions passed as arguments to other functions and executed when the operation is complete.

• Promises are objects that represent the eventual completion or failure of an asynchronous operation.

• Async/await is a newer syntax that allows writing asyn...read more
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Python technical SQL basic

Q1. Check if string is palindrome
Ans. 
Check if a string is the same forwards and backwards
• Iterate through the string from both ends and compare characters

• Use built-in functions like reverse() to check for palindrome

• Ignore spaces and punctuation when checking for palindrome
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Q1. Question on Binary trees: if symmetric, easy string question using hashmap
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Q2. If we are hosting a live test how to show real time ranking, HLD for this and what algorithms can we use
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Q1. Database schema design for a feature where user can be free, gold, platinum.
Ans. 
Use a user table with a column for user type (free, gold, platinum)
• Create a user table with columns for user ID, name, email, user type

• Use a separate table for user types with columns for type ID and type name

• Establish a one-to-many relationship between user and user type tables

• Example: user table - user_id, name, email, type_id; user_type table - type_id, type_name
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Q1. HLD for live rank dashboard for a live test where millions of users are doing test
Ans. 
High-level design for a live rank dashboard for a live test with millions of users.
• Use a scalable architecture to handle millions of users concurrently.

• Implement real-time data processing to update ranks dynamically.

• Utilize caching mechanisms to improve performance and reduce load on the database.

• Design a user-friendly interface with intuitive data visualization.

• Include features for filtering, sorting, and searching to
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Q1. Concepts of node and Js
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Two dynamic programming challenges at the hard level on LeetCode and 10 medium-level SQL challenge.