Goldman Sachs Interview Experience | Set 5 (On-Campus)

• Not many campuses around the world deal with “placement season” as we do in IITs. Only an IITian can understand the significance of December 1, the ultimate day when people from top Indian and international companies start to converge at one place to hire the supposedly best and brightest minds of the country. From toothpaste makers to software developers, there is perhaps no industry which is left unrepresented in the humongous crowd of recruiters who turn up for the event. Although I have personally benefited from this setting, I have strong views against it. But that demands a separate blog which I would write some other day.
• On 30th November. things were unexpectedly looking very rosy for me. I was shortlisted for interviews with almost all the companies which I had applied for based on my performance in their tests or my academic profile. I had got interviews with 8 companies in the whole day. It was definitely more than what a sane guy could handle. While planning for the order in which I would give the interviews, I decided to go based on my realistic chances of selection in them and not get carried away by my fancies and their fanciness. GS had always been my dream company, not only because it pays a hefty sum of money as salary, but because the best among the best had chosen it during previous years. There is no better parameter to judge a company than its people, and GS was definitely ahead of others according to my judgement.
• During my school years, I had always known that I was the smartest kid in my classroom. But that was definitely not the case in IIT where everybody comes after passing through a certain filtering process, where CPIs can be deceptive and where the laziest student could be the dark horse in the race. Every student of IIT is a combination of crass intelligence and “ability” to work hard. Since GS had shortlisted 69 candidates other than me, the realistic chances of me making through GS were rather less compared to other companies which had much shorter lists. I placed GS after 2 other companies (which also extended me job offers later) in my preference for interview timings. After revising basics of CS subjects and my projects, I was all set to face the battle with a reasonable amount of confidence.
• On a fateful day, Goldman Sachs started its interview process quite early at 12 am. My name appeared somewhere in the middle of the interview schedule list at 4.00 am which is the time when my body is adapted to go to sleep. I had not slept in 2 days because of the way our placement office had planned technical tests. All this meant that I would go to interview with tiredness from the past 3 days. The test venue was highly charged with all sorts of energies. There were many people who had already appeared for few rounds and, by then, had somehow figured out that they had been selected. For many of them, this turned out to be mere speculation later. I had heard that GS did not take other candidates seriously if they had found suitable ones already(This turned out to be a wrong notion later). I had a reason to worry. Going by their talks, there were many people in the corridor who had landed the job already.
• The interview process was running behind the scheduled time. The panel took a break, which meant I was not going to be interviewed up until 6 am. At 6:10 am, my name was called. My interviewer looked very weary after having participated in 6 hours long process already. A quick tricky question was asked about the Fibonacci series. I understood the question differently and gave solution to a more difficult problem. This got interviewer excited in interviewing me. I gained some confidence and insisted that I be given a chance to solve the original problem which I solved in no time. General resume discussion happened. I was asked how I thought GS made money. I realized that I had done a blunder by not researching the company properly before coming for the interviews. Nonetheless, reading pink newspapers helped. I answered the question. The interviewer was impressed, and so was I, with myself.
• Without a pause, I was called for the second round of interview. Since the interviewer was interviewing a filtered candidate, he looked more serious. General discussion on polity issues, macro economics and my course projects followed. Being aware of and having strong views on many public issues helped. The interviewer looked impressed with my answers. Then interviewer came to the actual business. A puzzle question was asked. I knew that it was a fairly popular puzzle but had never attempted it. This was the second big mistake that I had committed before coming for interviews. Although I like solving puzzles and solve one or two here and there, I had not practised and mugged them up in a way that other serious candidates would have done. But it seemed that I was destiny’s own child that day. The solution struck my mind. I later found out that that was indeed the standard solution to the problem. The interviewer wrote something on my resume and asked me to wait to be called for the third round.
• In the third round, the interviewer laid resume on a table without folding and I could see what other interviewers had written about me. “Strong yes” it read on the top. I felt good about it. I told the interviewer that I had done a course in algorithmic game theory. He asked some game theory questions which I answered. I knew I had nailed it. I was literally on high.
• Between third and fourth(final) round, I gave interviews to some other companies. The difficulty level of those interviews and my interest in them were nowhere close to the GS interviews. In fact, I felt bored during some interviews. I realized how much I wanted to be a part of GS already. I got a call for the fourth and final round of GS interview. While chanting Hanuman Chalisa quietly in my heart, I realized that I had forgotten it. I had not prayed in a long time and felt guilty for treating God so selfishly and took a mental note to make amends later. I needed divine intervention to help me to recall anything that I might need during the interview and to think clearly.
• The interview started without any needless talks. Once again, a puzzle was asked. I knew the solution to it and thought that I could bluff my interviewer by pretending that I did not. He called my bluff by asking a more difficult problem. It was loosely phrased. It was the first and only problem which I could not solve. But interviewer did not show any signs of disappointment. A strategy question was asked. I gave an algorithmic solution to it. He asked me to code it which I did. The interviewer looked happy.
• Without wasting a moment, I moved to give interviews to other companies leaving everything else in the hands of GS people and God. At the end of the first slot of interviews, I came to know that I had multiple offers and more choices in hand than I had imagined. It did not take me even a minute to choose Goldman Sachs. My life had taken a surprising turn which I had not thought about till that moment. I had become a part of the rich legacy which Goldman and Sachs had founded in 1869.

  Questions:

• Round 1:
  1. Given S(n) and F(n), two functions which compute sum of n Fibonacci numbers and nth Fibonacci number respectively in constant time. Write a funthe ction which computes sum of odd Fibonacci numbers in constant time.
  2. Now write a function to compute sum of Fibonacci numbers at odd indices in constant time.
  3. Write down function to select pivot element randomly in Quick Sort.
  4. Probability of comparison of two elements in random quick sort.
• Round 2:
  1. N door puzzle. ith user changes state of doors which are multiples of i. Calculate number of doors opened in the end.
  2. Some fairly simple DP coding problem(I don’t remember exact one).
• Round 3:
  Design a game (Automaton) for a betting scenario. Bet is either doubled or lost completely depending on whether you win or lose. Suppose you bet on team A constantly in a 2 team game, how much money you need initially so that you either win $100 or lose all at the end of game after 4 rounds.
• Round 4:
  1. randN function : which generates random number in [1,2,3..N] with equal probability. Given rand5, write a code for rand7 using rand5.
  2. Some number stream puzzle which I don’t recall.
  3. A strategy question. It would be asked depending on which team you are being interviewed for. Mine was some apple seller problem. Here knowledge of real world scenario helps. Advice is to observe things around you rationally.

All Practice Problems for Goldman Sachs !