PayPal Interview Experience for SDE II
Round 1(Data Structures & Algorithms): Self Introduction (5 min)
After that, they asked the below
- Find the element that occurs more than once(https://www.geeksforgeeks.org/array-elements-that-appear-more-than-once/)
- Find all elements that appear more than n/k times in an array.(https://www.geeksforgeeks.org/print-all-array-elements-appearing-more-than-n-k-times/)
- Given 2 nodes, Find LCA with parent pointer. I gave a HashMap based solution to store all paths till 2 nodes starting from root. They wanted a space optimised version, so kept track of parent pointer and checked for ancestors. Similar to intersection point of linked lists (https://www.geeksforgeeks.org/lowest-common-ancestor-in-a-binary-tree-set-2-using-parent-pointer/)
Round 2(System Design & DSA): In-depth description of current project architecture. Various trade-offs to be made.
- Explain Circuit breaker pattern: https://microservices.io/patterns/reliability/circuit-breaker.html
- Internal implementation of HashMap: https://www.geeksforgeeks.org/internal-working-of-hashmap-java/
- Difference between HashMap, HashTable. Which is thread-safe and why?
- Spring vs Spring boot framework(as mentioned in my resume)
- Completable future, lamba expressions, streams in Java 8+
Suggestion: Be very cautious while answering these questions, interviewers have a lot of in-depth knowledge.
Round 3(Managerial Round): This was a tough one. Started with current project and various trade-offs made in my design. Why we use this design pattern in code here. What are the advantages of the underlying architecture (we used: Hexagonal Architecture)
- Merge K sorted lists. (https://www.geeksforgeeks.org/merge-k-sorted-linked-lists/)
- Discuss internal structure of minHeap and maxHeap
- Fastest Sorting Algorithm (https://medium.com/javarevisited/sorting-algorithms-slowest-to-fastest-a9f0e30937b9)
- Given multiple files with different elements how to sort them into one file (without using extra space). https://www.geeksforgeeks.org/external-sorting/
- Design a RESTFul web service that can effectively perform CRUD operations
- Difference between @Controller & @RestController
- WebService versus REST API
- How Spring Boot solves the problems which Spring couldn’t solve
Tip: Do not try to jump directly to code. Discuss with the interviewer first. Do not bluff anything as they are highly knowledgable people.
For System, we are expected to write code sometimes, so have atleast sublime text. Do not use Office Laptops for interview.
Round 4(HR & Culture Fit) :
- Work location, Aspirations, Ambitions. Compensation benefits.
Author: Anjana Kesari