Third Year Summers Intern Interview Experience

I just had my interview at Tower Research Capital and the memories are fresh. This post might help someone in future or help me reminiscence.

The Countdown

We all were anxiously waiting for the companies to be appearing on the Internship Portal. The companies came in a group. Tower, Samsung Korea, DE Shaw, Goldman Sachs, and many other big companies booked for day 1. We started reading their proforma and researched about each company, who knew, what we had stored in our fate. So let’s begin! In this post, we shall talk only about Tower Research Capital. Fasten your seat belts guys :)

Branches Open For

Tower Research Capital was open for CSE, MnC, and EE. For people other than these branches, you have many other cool companies to apply for! Plenty of choices indeed!

The Preparation

After the display of company proforma, in between, one gets a lot of time to prepare for their choice of companies. I contacted my seniors. Had talks with people from previous batches who were Interning at Tower, and asked them about their experience. They all had one answer. The question that they ask in their interviews, cannot be prepared for. The questions have novelty and it’s hard to find them all in one place. One can only look at the previous year interview questions and get an idea of what kind of questions can be asked, but preparing for them specifically, well there was not a central resource. I hence started preparing for other coding tests that I had to clear (Tower doesn’t have a coding test round, only interview shortlisting. For others, they might shortlist for a coding/quant test and then on the basis of this result, students are shortlisted for interview rounds)

The Shortlisting

The shortlisting CPI criterion for Tower Research was not something high as 9.5. Many have a misconception about this. It was 8.0. They look at your key projects and work experience.
My View: Firstly, they state in the proforma, the CPI to be greater than 8.0, but I feel they are somewhat biassed for high CPI candidates. Secondly, they do look at competitive programming skills, what contests you have participated, achievements in them. Also, if not that, they look at decent coding skills. Plus on top of that, if you have some cool development projects, that is a huge bonus. A good CPI (say above 9.0) + competitive programming achievements +cool Development projects - that’s pretty much what my resume looked like. Lastly, a resume should be designed in a way that shows one’s curiosity to learn something new, representing one as busy doing things throughout the year, and must be intriguing. 8 were shortlisted for the interview.

Interview Process

They mentioned in their proforma, a technical round of 45 mins. Which, to my advantage, didn’t occur. I had 2 hours of interview with the people at Tower Research. The interview for Tower is held Phonic. People who get nervous in face to face interviews need not to worry in this case.

First Round

My first round was based on mathematics. It was a 1-hour phonic interview. Topics asked covered Probability (not that is taught in MSO 201, but more inclined towards finding Expectation Values), Recursive formulation of solutions in Maths, hard counting problems, a little Number Theory and finally some Algorithm related stuff. The questions that were asked were (tried my best maintaining the ordering of the questions as they were asked):

1. Prove that consecutive Fibonacci numbers are always co-prime.
2. 4 Foxes and 7 Hounds enter a cave in a straight line following a random ordering, find the expected no of foxes that are immediately followed by a Hound.
3. Find the number of binary strings of length n, that have at most k consecutive length of 1’s in them.
4. Find the probability that two consecutive heads doesn’t appear in n consecutive throws of an unbiased coin.
5. Given two random x and y values from 0 to 1 inclusive, state a method how you would choose a point in a 2-D plane inside a circle, centered at the origin with each point being equally likely, using x and y.
6. Given a rooted tree, find the points that have k distance between them.

Second Round

This was an algorithmic round. It was also for 1-hour and Phonic. The questions asked were:

1. A very long question about a dynamic Data Structure that required some special operations of a query and incrementing a certain counter variable on a daily basis from millions of user across the globe. Our task was to formulate Data Structure and algorithm for this job. The query gave the number of counter increments in the rolling window of the last second.
2. Given n pairs of numbers (x,y). We needed to form a binary tree, in which each node had values (x,y) such that x values formed a min-Heap, while y values formed a BST.
   After that, we had discussions about my projects and areas that interest me. The person at second round was better to talk with than the first one. I was able to convince him a lot better.
   
   

Results

The results came on the night of the 1st day of interviews. Four people were selected in Tower. And bang on, I was there! I also got selected in Samsung, South Korea as well. But I chose Tower over that!

Edit-Info (suggestion - Divyansh): It takes time to reach the solution. What they observe is the approach you take in solving and how innovative can you become in solving the problem. Once you solve some of the good problems, you are almost there.

Thanks for reading. All the best :)

That’s all folks!