Yahoo Interview | Set 3

Hi, I am Saurav Biswas, from IIT Kharagpur, currently doing my PhD in Machine Learning in Germany. I got hired at Yahoo SDC, India, in December (3rd to be precise) last year, through campus interviews. I was offered a position for Senior Software Engineer.

Interview consisted of a written test comprising of 25 objective questions, a coding round and then three technical and an HR round.

Here is the list of interviews in chronological order :

Round 1 : Written test
The round comprised of 25 objective questions from basic Algorithms , Data Structures , OS , Networking , databases and a few math puzzles. From this round, 20 people were selected for the next coding round . This written round was held sometime in the middle of November .

Round 2 : Coding
We were given an hour, and the problem was something like given a set of 2 dimensional pairs of points (floats/doubles) find out the two nearest points, for each point. I used recursive divide and conquer approach to solve it in O(nlgn) time. Later I was told to generalize the code for n points (pseudo code ) after my algo passed the test cases successfully .

From the coding round around 10 people were selected for the PI round of technical interviews .

Technical Interviews :

Round 1 :
I was posed a few questions on linked lists which I easily answered . The last question was that suppose you have implemented a search engine , you want to find if a URL typed by you is present in the cache of URLs that you have , more or less you have to give an optimized algo for it . I had read about suffix trees , the night before ( my good luck ) and I managed to code the problem with relative ease . The interviewer was satisfied and I qualified for the second Technical Interview .

Round 2 :
This time , the interviewer posed a math puzzle . I don’t remember it exactly , but it was something that the problem when framed mathematically would yield you an inequality in two variables , and you had to solve for the two unknowns . Initially I was in a fix , but the interviewer was kind enough to suggest me that i solve it heuristically . I started with base cases and proceeded up and finally the solution converged after a few iterations . The interviewer was satisfied . He then talked about what I would like to work on if I got an offer from Yahoo . Coming from a machine learning background , I was interested in working on the Yahoo Search Engine and he said he would definitely look into it . I was through that round .

Round 3 :
This time , the interviewer focused on Networking , OS and OOP concepts . I was asked to code the multiple Producer / Consumer problem , which I did . Then he asked a few questions on OOP , like difference between overloading and Overriding , virtual and friend functions and so forth . There was also a question on Iterators in JAVA . I had a strong grasp on OOP so I answered them . Finally he said he would like to ask me a question from Networking . He told me to explain the Leaky Bucket Algorithm . I didn’t know about it , so I said maybe he could ask me something else . So he asked me about TCP Three Way handshake . I did so more or less well .

Final Round : HR
The HR Interview was casual , asking me about personal interests , hobbies ( I told I played the guitar ) and what I would bring to if offered a job in Yahoo . She also asked me if I had any other companies in hand . I had none so I said I would like to go with the offer if I got it .

So finally I was hired in the position of a Senior Software Engineer . But I got a PhD offer from Germany in Machine Learning , so I declined the offer later in June .

As a note of advise to fellow aspirants , I would say that please read up Cormen and Tenenbaum for Algo / DS . I personally would like to thank g4g for their wonderful collection which is also a must . It helped me a lot too . Also people tend to screw up questions from OS/ Networking so keep basics like Synchronization, Process handling , Deadlocks , Memory management , TCP/IP clear . Read basic stuff for databases like primary keys , normalization and that should be it . Refer to xkcd for standard math puzzles .

Best of luck to all.

This article is compiled by Saurav Biswas. Many Many congratulations to Saurav for his selection. If you like GeeksforGeeks and would like to contribute, you can also write an article and mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks.

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