Schlumberger interview

Interview and experience.

5 min read    24 Aug 2017    

In my on-campus interviews, Schlumberger was one of the few companies to not conduct an online test to shortlist students for Software / Data profile. That could’ve been one of the reasons I was shortlisted for GD (Group Discussion).

Of around 70+ people who had applied, around 31 were shortlisted based on CGPA, or projects. The structure was simple. Once a topic was given, interviewees get a minute to think about the topic, and then they’re supposed to have a discussion for 20 minutes. People might be pointed out randomly and be asked to speak. The topics were fairly non-tech related and meant to check your general awareness, like “Do we need more entrepreneurs or managers?”, “Which is a bigger threat- Kim Jong Un or AI” or so. Here’s some unsolicited advice for Group Discussions.

  • In the 1 minute allotted, right down short points which you want to speak over in the GD.
  • You are going to have a dry throat even though you might be an extrovert. Try to speak up, there are no turns in GD.
  • Make sure you’re an active part of the conversation, and all your penned down thoughts are presented by you, not by someone else.
  • There are points for listening as well. If you can’t think of anything to speak, just listen and offer rebuttal.
  • Cold hard-hitting facts over emotions.
  • At the end of GD, after the interviewers have had to tolerate 3 or more GD’s, how are they going to remember you? Try to present some unique points that cannot be debated against. [This type of GD had you to speak either for or against the motion, no in-betweens]

GD results came in. 10 students were shortlisted, I was one of them. Since I did not have the first PI, I made sure I ask people before me what was asked. Seemed pretty standard. You should be able to defend your CV, and the subjects you’ve written as undertaken.

So, when it was my turn, I was relaxed, for I wasn’t concerned with the outcome of this interview. There are millions of companies where I could work in, this is just one of them. If they reject me, it’s their loss not mine. There were 3 interviewers, 2 techies (Software), and another senior employee (field-engineer turned HR) who was working there since 20 years or so.

Since I had written many projects in my CV, I was asked which project I enjoyed the most working on, and I duly replied Foodspark. It’s always better to cite a project with an active website, so they immediately opened the website. They asked why isn’t this secure. I replied, python hosting with Django / Flask is done over http, not https, so the website not being secure is do to python, not me. I was asked to explain what the project is about, what work I had precisely done, and what models were used in SQL.

I had written MongoDB and SQL in my CV, consequently I was asked to explain the difference between them. I stalled for a while, when they changed the question to, explain how mongo / SQL works (by this, I assumed I had to explain the basic working, which I did).

Now, one of the techies asked me why I had written C++ in my CV. Replied as being a part of the curriculum. “Is C++ managed memory or unmanaged memory?”. I kid you not, by the way the question was asked, I wasn’t sure I understood the question. I bluffed, managed memory. “What is managed memory ?” “No idea, I bluffed”. I later knew the question was almost correct, but I didn’t understand it then. C++ is unmanaged memory, you need to free pointers by yourself. Python in managed memory.

The interview’s focus then shifted to stacks and heaps. Asked what a stack is, and basic operations possible.[I know, this interview was way easy to be true]. Then asked a question, “Given a sorted stack, with the bottom most entry as the smallest, how will you insert a new element to ensure it is still sorted ?”. Pfft, another easy question. Keep popping off entries from the sorted stack into another stack, which is also sorted by the way, until you see a number smaller than the number to be inserted. Insert the new number, and empty the contents of the second stack into the sorted stack.

Asked to define heap property. Asked “How does C++ store variables ?”. Now, I knew the answer was stack memory or heap memory. So I replied, “I’m thinking out loud here, I know the answer is stack memory or heap memory”. On an instinct, I chose stack memory. We proceeded.

Given an array, which goes from 1 to n, and only one element is missing. How will you find this element.

-> Easy, sum = sum of elements. Missing number = n*(n+1)/2 - sum

Ok, in the same array, 2 numbers are missing, find them.

-> I knew the answer, but I stalled anyway. Say, a and b are missing. sum = sum of elements. prod = product of elements a + b = n(n+1)/2 - sum and ab = n! / prod.

“Okay, we like your approach, but not the answer we were expecting. Say if 3 numbers are missing”.

I almost facepalmed. They wanted count sort. Why don’t you give me some algo questions so that I know how well I’m actually doing ?

The basic idea, is c[1 to n] = 0. While scanning the array, if you encounter x, c[x] = 1. All elements with c[i] = 0 are missing.

My interview was almost coming to an end. The senior employee asked me, “Give me 10 things you can do with this chair”. This clearly involved some over-the-top solutions, and they expected them. I’m not going to tell you what I replied, and which 2 the interviewers suggested, but here are some things you can do, if you’re asked the exact question: Sit on it, stand on it to fix a tubelight, use it as a fight prop, use it as a dance prop, use it to generate fire( How else can I make up 10 uses?), can be used to float, use it as a scale, use it to break glasses in case of emergencies, and some more. Pretty out there, I know.

Lastly, I was asked what I did in my free time. Spoke the truth. Youtube AF. I justified saying, I watch character analysis of movies, so that I can analyse other humans better. (Wow reacts only)

Some things I realised about PI:

  • Confidence is the key.
  • If you’re stuck, and don’t speak for a while, that might count against you. Talk with you interviewers where you’re stuck, say “I’m thinking out loud, but”, or similar. They will help you.
  • I don’t think there’s any point in defending your mistakes in there. As a great man once said, “Let me give you some advice bastard. Never forget what you are. The rest of the world will not. Wear it like armor, and it can never be used to hurt you.”

I was selected.

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