Paytail Senior Software Engineer Interview Questions and Answers

It was about DS Algo and Java garbage collection,multithreading

Q1. Low level design of rate limiter
Ans. 
Rate limiter is a system that controls the rate of traffic sent or received by a network interface.
• Implement a token bucket algorithm to track and limit the rate of requests

• Use a sliding window algorithm to track the number of requests within a specific time frame

• Consider using a distributed rate limiter for scalability and fault tolerance
Answered by AI
Add your answer
Q2. Springboot basics, java basics, future interfaces, basic sql queries
Add your answer

Was a tough oneto crack

Q1. Asked about core Java domain and threds
Add your answer
Q2. Asked about Java domain and threads collection
Add your answer
Q3. Threads and collection
Add your answer

Q1. Questions based on DSA
Add your answer

Q1. Java specific Interview
Add your answer

Q1. Hiring Manager Interview
Add your answer

Machine coding round where SOLID principles are evaluated for real life use case

Machine coding round.

Q1. Algorithm to calculate top k flight from source to destinaton.
Ans. 
Use Dijkstra's algorithm to find the top k shortest paths from source to destination.
• Implement Dijkstra's algorithm to find the shortest paths from source to all other nodes.

• Store the top k shortest paths found in a priority queue or heap.

• Return the top k shortest paths as the result.
Answered by AI
Add your answer

Q1. Longest Consecutive Sequence
Ans. 
Find the length of the longest consecutive elements sequence in an array.
• Sort the array to ensure consecutive elements are adjacent

• Iterate through the array and keep track of the current consecutive sequence length

• Update the longest consecutive sequence length as you iterate
Answered by AI
Add your answer
Q2. Core Java Questions
Add your answer

Q1. Executor Service and it's code
Ans. 
Executor Service is a framework provided by Java for managing and executing asynchronous tasks.
• Executor Service allows you to easily create and manage threads for executing tasks.

• It provides a way to control the number of threads used for executing tasks, which can help prevent resource exhaustion.

• You can submit tasks to an Executor Service using methods like execute() or submit().

• Executor Service can be used to execut...read more
Answered by AI
Add your answer
Q2. Core Java and Spring boot questions
Add your answer

Q1. Design patterns
Add your answer
Q2. Core Java questions
Add your answer

Q1. Number of subset
Ans. 
Calculate the number of subsets of a given set
• The number of subsets of a set with n elements is 2^n

• Include the empty set and the set itself in the count

• For example, a set with 3 elements will have 2^3 = 8 subsets
Answered by AI
Add your answer
Q2. Remove kth node from end
Ans. 
Remove the kth node from the end of a linked list.
• Use two pointers, one to traverse the list and another to keep track of the kth node from the end.

• Once the first pointer reaches the end, the second pointer will be at the kth node from the end.

• Adjust the pointers to remove the kth node.
Answered by AI
Add your answer

Q1. Whatsapp low level design
Ans. 
Whatsapp low level design involves messaging, encryption, media sharing, and user authentication.
• Use end-to-end encryption to secure messages

• Implement message queues for real-time message delivery

• Allow media sharing through file transfer protocols

• Use OAuth for user authentication and authorization
Answered by AI
Add your answer
Q2. Lru implemention
Add your answer

Q1. Design a in-memory cache
Ans. 
Design a high-performance in-memory cache system for storing and retrieving data efficiently.
• Use a hash table or a key-value store to store data in memory

• Implement caching strategies like LRU (Least Recently Used) or LFU (Least Frequently Used) to manage cache eviction

• Consider using a distributed cache for scalability and fault tolerance

• Optimize cache size and expiration policies based on the application's data access
Answered by AI
Add your answer