D E Shaw Interview | Set 4 (On-Campus for Internship)

D. E. Shaw recently carried out intern procedure in our college. The whole process had three rounds.

Round 1:
It was CV shortlisting. Out of total 41 candidates, 12 were selected.

Round 2:
It was a telephonic interview. The call lasted 40 minutes. The interviewer asked about my academic project first. Next, he asked about my preference in a programming language – C/C++/JAVA. My preference was C++. So he started with OOP concepts. After I have named a few of the highlights of OOP, he asked about Data Encapsulation. He then demanded an example for the same. Few questions followed about the C++ implementation of the example that I had given. He then switched to virtual functions. Next came Inheritance, upcasting and downcasting, where should the virtual keyword be used.
He asked me how do we call the constructor of the base class using derived class. Next, he asked DS questions. There were three questions in total.

1. Given a string. How do we check if we can obtain a palindrome by rearranging the characters of the string.

2. Given a singly linked list. How to we detect if a loop is present in the list. (Both Brute-Force as well as Floyd’s Cycle Algorithm had to be explained in details).

3. Given a doubly linked list with a next pointer pointing to next node and other pointer pointing to any random node. How do we clone this list?

Round 3:
Last round was again a telephonic interview. This time too the call lasted 40 minutes. There were two interviewers this time. I was asked to explain one of my projects at the beginning. Then, I was asked to explain any of the projects.
Next, they asked me about STL, Generic classes and templates in C++. He then asked me to give an example of a class implemented using templates.
After this came the Data Structures part. This time, they asked me two questions. Both of them were related to real-life scenarios.
1. Given details of a person – First name, last name and telephone number. Sort them according to the last name. I said we can use qsort() and explained the whole process and design of comparator function. But they demanded an answer without using any of the library functions.

2. They next asked me given a number in the directory, how will you search for the person details from the directory. Your answer must be efficient enough so that it could be used on a map like Mumbai.

3. The next question was to implement a spell-check that is used in Microsoft Office Word and which data structure could be used to implement it.