Visa System Engineer Interview Questions and Answers

Q1. What is Java String pool?
Ans. 
Java String pool is a special memory area in Java heap where String literals are stored to optimize memory usage.
• String pool is a part of Java heap memory.

• String literals are stored in the String pool to avoid duplicate objects.

• Strings created using double quotes are stored in the String pool.

• Strings created using new keyword are not stored in the String pool.
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Q1. Did you have any conflicts with your peers and have did you handle it?
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There was a hacker rank assignment

Leetcode style question, medium

Q1. System design question normal
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Coding question of moderate difficulty

Q1. They asked Java coding question
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Round duration - 60 minutes
Round difficulty - Medium

Technical interview round where the Interviewer asked me questions based on data structures and algorithms.

Q1. 
Design a Constant Time Data Structure
Create a data structure that maintains mappings between keys and values, supporting the following operations in constant time:
1. INSERT(key, value): Add or update t...read more
Ans. 
Design a constant time data structure for key-value mappings with operations like INSERT, DELETE, SEARCH, GET, GET_SIZE, and IS_EMPTY.
• Use a hash table to store key-value pairs for constant time operations.

• Implement INSERT by hashing the key and storing the value at the corresponding index.

• For DELETE, simply remove the key-value pair from the hash table.

• SEARCH can be done by checking if the key exists in the hash table.

• ...read more
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Q2. 
Integer to Roman Conversion
Given an integer N, convert it to its corresponding Roman numeral representation. Roman numerals comprise seven symbols: I, V, X, L, C, D, and M.
Example:
Input:
N = 2
Outp...read more
Ans. 
Convert an integer to its corresponding Roman numeral representation.
• Create a mapping of integer values to Roman numeral symbols

• Iterate through the mapping in descending order of values and build the Roman numeral representation

• Handle special cases like 4, 9, 40, 90, 400, 900 separately

• Repeat the process for each digit of the input integer
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Round duration - 60 minutes
Round difficulty - Medium

Technical interview round where the Interviewer asked me questions based on data structures and algorithms.

Q1. 
Total Area of Overlapping Rectangles Problem Statement
Determine the total area covered by two given rectangles on a 2-D coordinate plane, which may have an overlapping area.
Input:
The first line conta...read more
Ans. 
Calculate the total area covered by two overlapping rectangles on a 2-D coordinate plane.
• Parse input coordinates for two rectangles

• Calculate the area of each rectangle

• Find the overlapping area by determining the intersection of the rectangles

• Calculate the total area by adding the areas of both rectangles and subtracting the overlapping area
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Q2. 
Longest Repeating Subsequence Problem Statement
Given a string st, your task is to determine the length of the longest repeating subsequence such that no two subsequences have the same character at the sa...read more
Ans. 
The task is to find the length of the longest repeating subsequence in a string with no same characters at the same position.
• Iterate through the string and find the longest repeating subsequence by comparing characters at different positions.

• Use dynamic programming to keep track of the longest repeating subsequence found so far.

• Ensure that no two subsequences have the same character at the same position.

• Example: For in...read more
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Round duration - 60 minutes
Round difficulty - Medium

This was a system design round.

Q1. How would you design a rate limiter?
Ans. 
Rate limiter can be designed using token bucket algorithm to control the rate of requests.
• Use token bucket algorithm to control the rate of requests

• Set a limit on the number of requests allowed within a certain time frame

• Track the number of requests made and refill the bucket at a constant rate

• Reject requests that exceed the limit
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DSA specific coding questions, arrays, stacks queues, trees mostly

Q1. DSA specific, may ask graphs ,dp
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Basic DSA and android questions

Live coding round for android

Q1. Explain your past experiences?
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Easy to medium level question with some mcqs

Then we had a training for one month and we created a project based on that project we were given internships