Visa

Q1. Maximum equal elements after K operations You are given an arbitrary array/list of integers 'ARR' of size ‘N’ and an integer ‘K’. You need to find the maximum number of elements which can be made equal to each ...

Question 2

Asked in

Q2. Stock Buy and Sell You have been given an array 'PRICES' consisting of 'N' integers where PRICES[i] denotes the price of a given stock on the i-th day. You are also given an integer 'K' denoting the number of p...

Question 3

Asked in

Q3. Ninja And The Dance Competetion Ninja has been asked to organize a dance competition. Ninja decided that he will take individual entries and then will divide them into pairs. As part of the entry, he asked the ...

Question 4

Asked in

Q4. Given a grid containing 0s and 1s and source row and column, in how many ways, could we reach form source to target. ( 1's represents a blockade and 0's represent accessable points)

Answer

Count the number of ways to reach target from source in a grid with 0s and 1s. Use dynamic programming to solve the problem efficiently. Traverse the grid using DFS or BFS to count the number of ways. Consider edge cases like when source and target are the same or when there is no path. Example: Given grid = [[0,0,0],[0,1,0],[0,0,0]], source = (0,0), target = (2,2), answer is 2. Example: Given grid = [[0,1],[0,0]], source = (0,0), target = (1,1), answer is 1.

Question 5

Asked in

Q5. Maximum length sub-array having absolute difference of adjacent elements either 0 or 1. Given an array ‘A’ of ‘N’ integers, you need to find the maximum length of the sub-array such that the absolute difference...

Question 6

Asked in

Q6. Given 2 game scenarios for basketball, and given p as the probability of making a basket in an attempt, I have to understand the condition where game1 would be preferable over game2. In first game, I have one t...

Answer

Comparing 2 basketball game scenarios with different number of trials and baskets required to win Calculate the probability of winning in each game scenario using binomial distribution formula Compare the probabilities to determine which game scenario is preferable In game1, the probability of winning is p. In game2, the probability of winning is the sum of probabilities of making 2 or 3 baskets If p is high, game1 is preferable. If p is low, game2 is preferable For example,...

Question 7

Asked in

Q7. Sorted order printing of a given array that represents a BST You have been given a Binary Tree of 'N' nodes, where the nodes have integer values. Your task is to find the In-Order traversal of the given binary ...

Question 8

Asked in

Q8. LRU Cache Implementation Design and implement a data structure for Least Recently Used (LRU) cache to support the following operations: 1. get(key) - Return the value of the key if the key exists in the cache, ...

Question 9

Asked in

Q9. Valid String You have been given a string 'S' containing only three types of characters, i.e. '(', ')' and '*'. A Valid String is defined as follows: 1. Any left parenthesis '(' must have a corresponding right...

Question 10

Asked in

Q10. Number of Pairs with Given Sum You have been given an integer array/list(arr) and a number 'Sum'. Find and return the total number of pairs in the array/list which when added, results equal to the 'Sum'. Note: ...

Question 11

Asked in

Q11. Longest Common Subsequence You have been given two Strings “STR1” and “STR2” of characters. Your task is to find the length of the longest common subsequence. A String ‘a’ is a subsequence of a String ‘b’ if ‘a...

Question 12

Asked in

Q12. System Design problem
What to do if there are too many requests to a web server? Don’t know if they’re correct. I feel it was a more test to see your critical thinking and acquired knowledge.

Question 13

Asked in

Q13. Minimum Cost to Reach End You are given an array “ARR” of 'N' integers and an integer 'K'. You can move from any index 'i' to index 'j' if j ≤ i + K. The cost of moving from one index 'i' to the other index 'j'...

Question 14

Asked in

Q14. 1. High Level System Design -> Design Uber like Service. Follow up -> What would be your tech stack for designing such a service to make sure it could scale when needed.

Answer

Tech stack for designing a scalable Uber-like service. Use microservices architecture for scalability and fault tolerance. Choose a cloud provider with auto-scaling capabilities. Use a load balancer to distribute traffic across multiple instances. Use a NoSQL database for high availability and scalability. Use message queues for asynchronous communication between services. Use containerization for easy deployment and management. Use caching to improve performance. Use monito...

Question 15

Asked in

Q15. Four Keys Keyboard Imagine you have a special keyboard with the following four keys: Key 1: (A): Print one ‘A’ on screen. Key 2: (Ctrl-A): Select the whole screen. Key 3: (Ctrl-C): Copy selection to buffer. Key...

Question 16

Asked in

Q16. Second Most Repeated Word You are given an array of strings ‘ARR’. You have to find out the second most repeated word in the array ‘ARR’. It is guaranteed every string occurs a unique number of times in the arr...

Question 17

Asked in

Q17. Graph Connectivity Queries. You have been given a graph consisting of ‘N’ nodes and a threshold value ‘THRESHOLDVALUE’. Two different nodes ‘X’ and ‘Y’ are directly connected to each other if and only if there ...

View 2 more answers

Question 18

Asked in

Q18. N Queens You are given an integer 'N'. For a given 'N' x 'N' chessboard, find a way to place 'N' queens such that no queen can attack any other queen on the chessboard. A queen can be killed when it lies in the...

View 2 more answers

Question 19

Asked in

Q19. (HLD) -> Design a service which combines multiple sources of data/documentation and aggregates it such that all info is available centrally.

Answer

Design a service to aggregate multiple sources of data/documentation centrally. Identify sources of data/documentation Determine data aggregation method Design a centralized database to store aggregated data Develop a user-friendly interface to access the data Ensure data security and privacy

Question 20

Asked in

Q20. Basic HR Questions
Q1. What are the three problems Chennai faces?
Q2. Which one would you solve and how and why?
Q3. What is the most interesting thing about Visa?

Question 21

Asked in

Q21. Snake and Ladder You have been given a Snake and Ladder Board with 'N' rows and 'N' columns with the numbers written from 1 to (N*N) starting from the bottom left of the board, and alternating direction each ro...

Question 22

Asked in

Q22. What is most interesting thing about Visa?

Answer

Visa is a global payments technology company that connects consumers, businesses, banks and governments in more than 200 countries and territories. Visa operates the world's largest retail electronic payments network. VisaNet, the company's global processing system, handles more than 65,000 transaction messages a second. Visa is constantly innovating to improve payment security and convenience, with initiatives such as Visa Checkout and tokenization. Visa is committed to fin...

Question 23

Asked in

Q23. Design Pattern Question
What is Observer Pattern?

Question 24

Asked in

Q24. Java Question
How to create an immutable class in java?

Question 25

Asked in

Q25. Given a monolith architecture, how would you scale it to handle 3x the traffic and also improve response time on API's during peak hours by using cache

Answer

To scale a monolith architecture and improve response time, use horizontal scaling and implement caching. Implement horizontal scaling by adding more instances of the monolith application behind a load balancer Use a distributed cache to store frequently accessed data and reduce database queries Implement caching at different levels such as application-level caching, database query caching, and HTTP response caching Use a caching strategy based on the data access patterns an...

Question 26

Asked in

Q26. What is race condition and how can it be eliminated

Answer

Race condition is a situation where multiple threads/processes access and manipulate shared data simultaneously. It can be eliminated by using synchronization techniques like locks, semaphores, and mutexes. Another way is to use atomic operations that ensure the data is accessed and modified atomically. Using thread-safe data structures can also prevent race conditions. Example: Two threads trying to increment a shared variable simultaneously can cause a race condition. Exam...

Question 27

Asked in

Q27. Software Engineering Question
What is dependency injection?

Question 28

Asked in

Q28. Which one would you solve and how and why?

Answer

Need more context on the question to provide an answer. Please provide more information on the problem to be solved. Without context, it is difficult to provide a solution. Can you please provide more details on the problem statement?

Question 29

Q29. Analytic que- Two trains start from equator and start running in different direction and they will never collide…so which train will have more wear n tear first…9use concept of rotation,relative motion and air ...

Answer

Two trains starting from equator in opposite directions will not collide. Which train will have more wear and tear first? The train moving towards the east will have more wear and tear due to the rotation of the earth The train moving towards the west will have less wear and tear due to the rotation of the earth Air resistance will also affect the wear and tear of the trains The train moving towards the east will face more air resistance than the train moving towards the wes...

Question 30

Asked in

Q30. Java Question
What is immutable in java?

Question 31

Asked in

Q31. Given two sorted arrays, a (m elements, size m+n) and b (n elements, size n) merge both the arrays into the first array a.

Answer

Merge two sorted arrays into the first array Start from the end of both arrays and compare elements Place the larger element at the end of the first array Continue this process until all elements are merged

Question 32

Asked in

Q32. Given the above Binary search tree, print in ascending order

Answer

Print the given Binary search tree in ascending order Traverse the left subtree recursively Print the root node Traverse the right subtree recursively

Question 33

Asked in

Q33. What are three problems Chennai faces?

Answer

Chennai faces problems related to water scarcity, traffic congestion, and pollution. Water scarcity due to inadequate rainfall and poor management of water resources. Traffic congestion due to the increasing number of vehicles and poor road infrastructure. Pollution caused by industries, vehicular emissions, and improper waste disposal.

Question 34

Asked in

Q34. Given an array, Implement Binary search tree

Answer

Implement Binary Search Tree using given array of strings. Sort the array in ascending order Find the middle element and make it the root of the tree Recursively create left and right subtrees using the left and right halves of the array Repeat until all elements are added to the tree

Question 35

Asked in

Q35. OOPS Question
What is singleton class?

Question 36

Asked in

Q36. how does ajax call work

Answer

Ajax calls allow for asynchronous communication between client and server without reloading the page. Ajax stands for Asynchronous JavaScript and XML Uses XMLHttpRequest object to send and receive data Allows for partial page updates without reloading the entire page Can handle data in various formats such as JSON, XML, HTML, and plain text Example: $.ajax({url: 'example.com', success: function(data){console.log(data)}});

Question 37

Asked in

Q37. how do you create immutable in java

Answer

Creating immutable in Java Use final keyword to make variables immutable Use private constructor to prevent object modification Use defensive copying to prevent modification of mutable objects Use enum to create immutable objects Use String class to create immutable strings

Question 38

Asked in

Q38. API Question
Difference between SOAP and REST

Question 39

Asked in

Q39. Class design for a cache implementation, implement get(), put(), initialization methods

Answer

Design a cache class with get(), put(), and initialization methods. Define a class with a data structure to store key-value pairs. Implement a get() method to retrieve a value from the cache based on a given key. Implement a put() method to add or update a key-value pair in the cache. Implement an initialization method to set the initial capacity and eviction policy of the cache. Consider using a hash map or a linked list to store the key-value pairs efficiently. Handle cach...

Question 40

Asked in

Q40. where have you used immutable in java

Answer

Immutable is used in Java to create objects whose state cannot be changed after creation. Immutable objects are thread-safe and can be shared without the risk of data corruption. Examples of immutable classes in Java include String, Integer, and LocalDate. Immutable objects can be created using the final keyword, constructor initialization, and static factory methods.

Question 41

Asked in

Q41. AJAX Question
How does AJAX work?

Question 42

Asked in

Q42. How Visa works Can you design a scalable file access system like dropbox or google drive?

Answer

Visa is a payment processing company that facilitates electronic funds transfers globally. Visa operates a network that connects financial institutions, merchants, and consumers worldwide. The company provides payment products and services, including credit and debit cards, prepaid cards, and digital wallets. Visa's payment processing system involves authorization, clearing, and settlement of transactions. To design a scalable file access system like Dropbox or Google Drive,...

Question 43

Asked in

Q43. API Question
Difference between GET and POST

Question 44

Q44. What is your project? If you are going to deploy this for commercial use, what additional aspects to be taken care of?

Answer

My project is a mobile app that helps users track their daily exercise and nutrition. Ensure the app is user-friendly and intuitive Implement a secure login and authentication system Integrate with fitness trackers and nutrition databases Perform thorough testing and bug fixing Consider scalability and performance optimization Implement a monetization strategy for commercial use

Question 45

Q45. Where should u prefer BUS topology instead of ring topology and vice verse

Data Engineering Intern Interview

Answer

BUS topology is preferred for small networks while ring topology is preferred for larger networks. BUS topology is easier to install and maintain than ring topology. Ring topology is more fault-tolerant than BUS topology. BUS topology is suitable for small networks with few devices while ring topology is suitable for larger networks with many devices. Ring topology is more expensive than BUS topology. Examples of BUS topology include Ethernet and USB while examples of ring t...

Question 46

Asked in

Q46. Explain the Concepts of OOPS , abstraction inheritance polymorphism and encapsulation.

Answer

OOPS concepts include abstraction, inheritance, polymorphism, and encapsulation. Abstraction: Hiding implementation details and showing only necessary information. Inheritance: Creating new classes from existing ones, inheriting properties and methods. Polymorphism: Using a single method to perform different actions based on the object type. Encapsulation: Binding data and methods together, protecting data from outside interference.

Question 47

Asked in

Q47. Calculate the time taken by kth person to collect n number of tickets

IT/Technical Content Developer Interview

Answer

The time taken by the kth person to collect n number of tickets can be calculated using a formula. Use the formula: time = (n - 1) * k Subtract 1 from n because the first person doesn't need to wait for anyone Multiply the result by k to get the time taken by the kth person Example: If n = 5 and k = 3, the time taken by the 3rd person would be (5 - 1) * 3 = 12

Question 48

Asked in

Q48. What all things do you find on a cerdit/debit card?

Answer

A credit/debit card typically contains the cardholder's name, card number, expiration date, and security code. Cardholder's name Card number Expiration date Security code/CVV Card issuer logo Magnetic stripe Chip Contactless payment symbol

Question 49

Asked in

Q49. what is observer pattern

Answer

Observer pattern is a design pattern in which an object maintains a list of its dependents and notifies them automatically of any state changes. Also known as publish-subscribe pattern Used in event-driven systems Allows loose coupling between objects Example: A weather station broadcasts weather updates to multiple displays Example: A stock market ticker notifies multiple investors of stock price changes

Question 50

Q50. Unit Testing (Code a given problem and generate test cases for unit testing)

Senior Systems Engineer Interview

Answer

Unit testing involves testing individual units of code to ensure they function as expected. Identify the individual units of code to be tested Create test cases for each unit, covering all possible scenarios Execute the tests and analyze the results Refactor the code as necessary based on the test results

Question 51

Asked in

Q51. Which application you are using to connect servers?

Answer

I primarily use SSH (Secure Shell) to connect servers. SSH (Secure Shell) is a widely used application for securely connecting to servers Other applications like PuTTY, OpenSSH, and WinSCP can also be used for server connections

Question 52

Asked in

Q52. Explain Testing principles and Design principles

Answer

Testing principles ensure software quality, while design principles guide software development. Testing principles include unit testing, integration testing, and acceptance testing. Design principles include SOLID, DRY, and KISS. Testing principles ensure that software meets requirements and is free of defects. Design principles guide software development to be modular, maintainable, and scalable.

Question 53

Asked in

Q53. difference between REST and SOAP

Answer

REST is lightweight and uses HTTP while SOAP is XML-based and has more features. REST uses HTTP methods like GET, POST, PUT, DELETE while SOAP uses XML messaging. REST is stateless while SOAP can maintain state. REST is faster and easier to use while SOAP is more secure and reliable. REST is used for web services while SOAP is used for enterprise-level services. Example of REST: Twitter API. Example of SOAP: Amazon Web Services.

Question 54

Q54. how would you propose a solution to DoS , network attacks

Answer

A multi-layered approach is needed to prevent DoS and network attacks. Implement firewalls and intrusion detection systems Use load balancers to distribute traffic Regularly update software and security patches Limit access to sensitive data and systems Educate employees on safe browsing habits and phishing scams

Question 55

Asked in

Q55. Design a custom data structure based on requirement

Answer

Custom data structure for array of strings Use a trie data structure to efficiently store and search for strings Implement methods for adding, removing, and searching for strings in the trie Consider optimizing the trie for memory usage and performance

Question 56

Asked in

Q56. internal working - of DB structures and indices etc

Answer

Understanding internal workings of DB structures and indices is crucial for optimizing database performance. DB structures refer to how data is organized within a database, such as tables, columns, and relationships. Indices are data structures that improve the speed of data retrieval operations by providing quick access to specific data values. Understanding how indices work can help in optimizing query performance by reducing the number of rows that need to be scanned. Com...

Question 57

Asked in

Q57. write code in python using pandas to perform certain tasks

Answer

Using pandas in Python to perform tasks for a Software Engineer interview question Import pandas library Read data from a CSV file using pandas Perform data manipulation and analysis using pandas functions Write the processed data back to a new CSV file

Question 58

Q58. What kind of data mining can be done on VISA data? What are the uses?

Answer

Data mining on VISA data can provide insights on consumer spending patterns and fraud detection. Identifying consumer spending habits and preferences Detecting fraudulent transactions and patterns Analyzing purchasing trends and market behavior Predicting customer churn and loyalty Optimizing marketing campaigns and personalized offers

Question 59

Asked in

Q59. what is immutable in java

Answer

Immutable in Java refers to objects whose state cannot be changed after creation. String, Integer, and other wrapper classes are immutable in Java. Immutable objects are thread-safe and can be shared without synchronization. To create an immutable class, make all fields final and private, and don't provide setters. Examples of immutable classes in Java include LocalDate, LocalTime, and LocalDateTime.

Question 60

Asked in

Q60. what is dependency injection

Answer

Dependency injection is a design pattern that allows objects to receive dependencies rather than creating them internally. It helps to decouple the code and makes it more testable and maintainable. It allows for easier swapping of dependencies without changing the code. There are three types of dependency injection: constructor injection, setter injection, and interface injection. Example: Instead of creating a database connection object inside a class, the object is passed ...

Question 61

Asked in

Intern Interview

Q61. N-Queens, Snake and Ladder Problem, Second Most repeated word in a sequence

IT/Networking-Manager Interview

Answer

These are three different programming problems that require different approaches to solve. N-Queens: placing N queens on an NxN chessboard so that no two queens threaten each other Snake and Ladder Problem: finding the minimum number of dice rolls to reach the end of a board with snakes and ladders Second Most Repeated Word in a Sequence: finding the second most frequently occurring word in a given sequence of words

Question 62

Asked in

Q62. How would modify a gmail notifier ?

Answer

To modify a Gmail notifier, you can customize its appearance, add additional features, or integrate it with other applications. Customize the notifier's appearance by changing its color, font, or notification sound. Add additional features such as the ability to mark emails as read or reply directly from the notifier. Integrate the notifier with other applications like a task manager or calendar to display reminders or deadlines. Implement filters to only receive notificatio...

Question 63

Asked in

Q63. What is regression testing?

Answer

Regression testing is the process of testing changes made to a software application to ensure that existing functionality still works. It is performed after making changes to the software It ensures that existing functionality is not affected by the changes It helps to catch any defects or bugs that may have been introduced It can be automated using testing tools Examples include retesting after bug fixes, testing after new features are added

Question 64

Asked in

Q64. what is GET and POST