PTC Vapt Engineer Interview Questions and Answers

Q1. Find longest palindromic substring in a given string.
Ans. 
Use dynamic programming to find the longest palindromic substring in a given string.
• Iterate through the string and expand around each character to find palindromes.

• Store the length of the longest palindrome found so far.

• Return the substring based on the start and end indices of the longest palindrome.
Answered by AI
Add your answer
Q2. How to serialize and deserialise a tree
Ans. 
To serialize and deserialize a tree, use a recursive approach to traverse the tree and store the data in a suitable format.
• Use pre-order traversal to serialize the tree by storing the node values in a list or string.

• For deserialization, reconstruct the tree by recursively building nodes from the serialized data.

• Consider using JSON or XML format for serialization to easily store and retrieve tree structure.
Answered by AI
Add your answer
Q3. Find if a given regex (containing ., * and lower case english chars) matches a given string.
Ans. 
Use regex library to match given regex with string.
• Use a regex library like re in Python to match the given regex with the string.

• Check if the regex matches the string using the library functions.

• Handle cases where the regex contains special characters like . and * appropriately.
Answered by AI
Add your answer
Q4. Explain about throttling and implement throttle function.
Ans. 
Throttling is a technique used to control the rate of requests sent to a server.
• Throttling helps prevent server overload by limiting the number of requests processed at a time.

• Implementing a throttle function involves setting a maximum request rate and delaying excess requests.

• Example: Implementing a throttle function in a web application to limit the number of API calls made to a third-party service.

• Example: Throttlin...read more
Answered by AI
Add your answer

Q1. Find squares of elements in a sorted array and return the sorted response.
Ans. 
Sort the squares of elements in a sorted array and return the sorted response.
• Iterate through the array and square each element.

• Store the squared values in a new array.

• Sort the new array and return it.
Answered by AI
Add your answer
Q2. Write a short promise example and implement your own promise
Ans. 
A promise is a commitment to do something in the future, typically used for asynchronous operations in JavaScript.
• Promises are used to handle asynchronous operations in JavaScript.

• They represent a value that may be available now, in the future, or never.

• Promises have three states: pending, fulfilled, or rejected.

• Example: new Promise((resolve, reject) => { setTimeout(() => resolve('Done!'), 1000); });
Answered by AI
Add your answer
Q3. Explain event loop, what are different types of queues in event loop
Ans. 
Event loop is a mechanism that allows for asynchronous execution of code by managing the order of events in a single thread.
• Event loop continuously checks the call stack for any functions that need to be executed, and processes them in a non-blocking manner.

• Different types of queues in event loop include microtask queue (Promise callbacks), macrotask queue (setTimeout, setInterval callbacks), and animation frame queue
Answered by AI
Add your answer
Q4. What is virtual DOM and why its faster
Ans. 
Virtual DOM is a lightweight copy of the actual DOM, used to improve performance by minimizing direct manipulation of the real DOM.
• Virtual DOM is a concept used in frameworks like React to optimize rendering performance.

• Changes are first made to the virtual DOM, which is then compared to the real DOM to identify the minimal updates needed.

• This approach reduces the number of actual DOM manipulations, resulting in faster...read more
Answered by AI
Add your answer

Q1. Explain OOPS concept and how you apply it in your implementation
Ans. 
OOPS is a programming paradigm based on the concept of objects, which can contain data in the form of fields and code in the form of procedures.
• OOPS focuses on the concept of classes and objects

• Encapsulation: bundling data and methods that operate on the data within a single unit

• Inheritance: allows a class to inherit properties and behavior from another class

• Polymorphism: ability to present the same interface for diffe...read more
Answered by AI
View 1 more answer
Q2. Difference between Comparable and Comparator. Difference between Abstract Class and Interface
Ans. 
Comparable is an interface used for natural ordering, Comparator is an interface used for custom ordering. Abstract class can have method implementations, Interface cannot.
• Comparable interface is used to define the natural ordering of objects. Example: String class implements Comparable interface for natural ordering based on alphabetical order.

• Comparator interface is used to define custom ordering of objects. Example:...read more
Answered by AI
View 1 more answer
Q3. Given a string. Find the number of occurrences of each character
Ans. 
Count occurrences of each character in a given string
• Create an array to store the count of each character

• Iterate through the string and increment the count of each character in the array

• Return the array with counts for each character
Answered by AI
Add your answer
Q4. Given an array. Remove the number of duplicates
Ans. 
Remove duplicates from an array of strings
• Iterate through the array and store each element in a set to keep track of unique values

• Create a new array with the unique values from the set
Answered by AI
Add your answer
Q5. Given a student object having name and grade data variables. Sort the object on the basis of highest grade.
Add your answer

Q1. Basic java fundamentals
Add your answer
Q2. Spring boot,sql
Add your answer

Q1. Some technical questions from manager
Add your answer
Q2. Some challenges or scenario based questions
Add your answer

Q1. Salary discussion mostly
Add your answer
Q2. Benifts that they offer with TR
Add your answer

Q1. What is the inheritance?
Ans. 
Inheritance is a mechanism in object-oriented programming where a class inherits properties and behaviors from another class.
• Allows a class to inherit attributes and methods from another class

• Promotes code reusability and reduces redundancy

• Creates a parent-child relationship between classes

• Derived class can override or extend the functionality of the base class
Answered by AI
Add your answer
Q2. What are the types of joins in mysql
Ans. 
Types of joins in MySQL include inner join, left join, right join, and full join.
• Inner join: Returns rows when there is a match in both tables.

• Left join: Returns all rows from the left table and the matched rows from the right table.

• Right join: Returns all rows from the right table and the matched rows from the left table.

• Full join: Returns rows when there is a match in one of the tables.
Answered by AI
Add your answer

Q1. How to handle multiple api's
Ans. 
Use a centralized API gateway to manage and route requests to multiple APIs efficiently.
• Implement a centralized API gateway to handle incoming requests and route them to the appropriate API based on the endpoint.

• Utilize API management tools like Apigee, Kong, or AWS API Gateway to manage and monitor multiple APIs.

• Consider implementing a caching layer to improve performance and reduce the number of requests to external
Answered by AI
Add your answer
Q2. What does strstr function do?
Ans. 
strstr function searches for a substring within a string and returns a pointer to the first occurrence of the substring.
• Used in C programming language

• Syntax: char *strstr(const char *haystack, const char *needle)

• Example: char *str = strstr("hello world", "world")
Answered by AI
Add your answer

Karat Interview for next filtering the candidate

Q1. Design Snake Game (Nokia based)
Ans. 
Design a classic Snake game based on Nokia phones.
• Use a 2D array to represent the game board.

• Implement logic for snake movement and growth.

• Include collision detection with walls and itself.

• Add food items for the snake to eat and grow.

• Display the game on a grid-based interface.
Answered by AI
Add your answer
Q2. Ballot based voter
Add your answer

Normal vikas questions

Q1. Cube root,double pointers
Add your answer
Q2. Projects embedded expected
Ans. 
Projects involving embedded systems are expected in the software engineer role.
• Experience with programming languages commonly used in embedded systems such as C/C++

• Knowledge of hardware-software interface and real-time operating systems

• Ability to work with microcontrollers and sensors

• Examples: Developing firmware for IoT devices, designing control systems for robotics
Answered by AI
Add your answer

Q1. Normal hr questions
Add your answer
Q2. Job location and projects
Add your answer

Q1. Linkedlist , array, stack
Add your answer
Q2. What is big data
Ans. 
Big data refers to large volumes of structured and unstructured data that is too complex for traditional data processing applications.
• Big data involves processing and analyzing large volumes of data to uncover patterns, trends, and insights.

• It can come from various sources such as social media, sensors, devices, and business transactions.

• Examples of big data technologies include Hadoop, Spark, and NoSQL databases.

• Big d...read more
Answered by AI
Add your answer