Simplilearn Sdet Engineer Interview Questions and Answers

Easy leetcode code 2 questions , HTML5 css javascript simple screen design

Q1. Oop, Simple coding javascript, react basic, sql basic
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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
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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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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. Tell me about yourself
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Q2. Coding Question
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Q1. Tell me about yourself
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Q2. Salary discussion
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Python technical SQL basic

Two dynamic programming challenges at the hard level on LeetCode and 10 medium-level SQL challenge.

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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