PayPal Interview Experience SE 2

I got the opportunity to attend the interview through one of my closest friends' referral for a vacant position in his team.

Round 1(1 hour): This was a DS and Algorithms round conducted by one of the SDE3s.

1. Remove nth duplicate element from the given linked list.

   Eg: 1 -> 2 -> 3 -> 1 -> 2 -> 3 ->1 ->2 ->3, n=2
   Here the nth(2nd) duplicate
   element in this list is 2. 
   So return, 1 -> 3 -> 1 -> 3 -> 1 -> 3

2. Write a program to read all the files in the given directory and returns a dictionary (JSON-like structure) that contains occurrences of every word in each of its respective file names. JavaScript

   //Eg:
   
   {
   
   "hello" : {
               "file1.txt": 2,
               "file2.txt": 6
               },
   "world" : {
               "file2.txt": 3,
               "file10.txt": 7
              },
   }
   

3. How do message queues work (Focused on Kafka and Zookeeper) and their uses with a real-time example?
4. Explain one of the projects that you have worked on in your previous company.
5. Some basic questions on Python (Available inbuilt data structures, default debugger module available, etc).

PS: This hiring was specifically for Engineers skilled in Python Django, ReactJS, and Java. Though I don't know Django, the interviewer was fine.

Round 2(1 hour): This round was conducted by one of the Engineering Lead members from the US office. This round was like pair programming which was to basically design (Low Level) a payments application with the following use cases. I was not paired with any other candidate. The interviewer himself acted as my pair and helped me whenever I got stuck in the middle.  

1. Users can add credit cards.
2. Check if it is a valid credit card
3. Make transactions/transfers from one user to another.
4. Check if the balance is available from the source account and then allow to transfer money to others who have linked their cards.  
5. Proper logging and error handling.

He expected a full working code with proper test cases.

Round 3(10 minutes): This was conducted by the Hiring Manager.

1. Why are you looking for a job change?
2. Discussions on my work with previous projects in previous companies.