Paisabazaar.com Backend Developer Interview Questions and Answers

Q1. DSA Medium difficulty question Schema Design Low level design Amazon reviews page
Add your answer

It was on-campus placement interview.
Two rounds of interview were there and both were of DSA (DP and sorting algo).

Given two soted arrays merge them from a single sorted array with all items in non-decreassing order

3 Leetcode style questions , 2 medium , 1 hard .

Q1. Design a cab booking system using oops
Ans. 
A cab booking system designed using OOP principles
• Create classes for Cab, Customer, Driver, and Booking

• Use inheritance and polymorphism to handle different types of cabs and bookings

• Implement methods for booking a cab, assigning a driver, and calculating fare

• Use encapsulation to protect data and ensure data integrity
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Easy

Q1. 
0/1 Knapsack Problem Statement
A thief is planning to rob a store and can carry a maximum weight of 'W' in his knapsack. The store contains 'N' items where the ith item has a weight of 'wi' and a value of...read more
Ans. 
Yes, the 0/1 Knapsack problem can be solved using dynamic programming with a space complexity of not more than O(W).
• Use a 1D array to store the maximum value that can be stolen for each weight capacity from 0 to W.

• Iterate through each item and update the array based on whether including the item would increase the total value.

• The final value in the array at index W will be the maximum value that can be stolen.
Answered by AI
Add your answer
Q2. 
Find the Second Largest Element
Given an array or list of integers 'ARR', identify the second largest element in 'ARR'.
If a second largest element does not exist, return -1.
Example:
Input:
ARR = [2,...read more
Ans. 
Find the second largest element in an array of integers.
• Iterate through the array to find the largest and second largest elements.

• Handle cases where all elements are identical.

• Return -1 if a second largest element does not exist.
Answered by AI
Add your answer

Round duration - 60 Minutes
Round difficulty - Easy

System Design Round

Q1. Design a system for Twitter, discussing its architecture, key components, and scalability considerations.
Ans. 
Design a scalable system for Twitter with key components and architecture.
• Use microservices architecture for scalability and fault isolation.

• Key components include user service, tweet service, timeline service, and notification service.

• Use a distributed database like Cassandra for storing tweets and user data.

• Implement a message queue like Kafka for handling real-time updates and notifications.

• Use a caching layer like ...read more
Answered by AI
Add your answer

Round duration - 30 Minutes
Round difficulty - Easy

It is just a formality