Round 1: Online coding round conducted on Hacker Rank (60 minutes)
Four Sections –
- First section, Time – 20 minutes
1 coding question Given a string of lowercase letters find no of distinct characters in every window of size k. 1<=length of string<=10^5, 1<=k<=length of string
It was a simple question which could have been done by sliding the window and keeping count of characters in an array of size 26 for every window. Time Complexity – O(N)
Similar question – https://www.interviewbit.com/problems/distinct-numbers-in-window/
- Second Section, Time – 15 minutes
10 aptitude questions. Questions were tough given the limited time.
- Third Section, Time – 15 minutes
10 questions on Data Structures. Questions were simple if your basics are clear.
- Fourth Section, Time – 10 minutes
5 questions on Linux, Networking.
Round 2: FTF Technical Round (1 hours and 30 minutes)
This was a really hectic round the interviewer asked questions from almost all the topics(OS, Networking, Data Structures, Puzzles, DBMS).
- A puzzle similar to https://www.geeksforgeeks.org/puzzle-18-torch-and-bridge/. He also asked me to write the code for it for a general case when there are n persons.
- All sorting algorithms with their time and space complexity. Derivation of time complexity for Quick, Merge and Heap Sort.Which are stable and when to prefer one over the other.He also asked me to write the Code of Merge, Quick and Radix Sort.
- Painter partition problem – https://www.geeksforgeeks.org/painters-partition-problem-set-2/ Hint – Use Discrete Binary search.
- All triplets with zero sum.
- Advantages of Linux over windows. Why developers prefer linux? Differences b/w them.
- Static and Dynamic Linking. Advantages, differences between them? When to use which one.
- Static variables and functions in C++. Use and differences between static and global variables.
- Storage Classes in C++.
- What are cin and cout in C++. They are objects of which class.
- Namespaces in C++.
- Joins in SQL.
- Trigger, Stored Procedure and Cursor. Difference and Uses.
- Some SQL queries related to joins.
- Normalisation in Database. Types of Normal Forms and why is normalisation required?
- Layers in OSI Model. Use of each layer.
- What happens when you type a www.google.com in your browser.How is message send in each layer from your PC to the router and so on till the message reaches to the servers of google. Structure of data in each layer like frame in DLL, Packet in NL, Segment in TL. How are IP and Mac address changed and protocols used(ARP, RARP, BOOTP, DHCP).
- Explain TCP protocol, sequence no, acknowledgement no, wrap around time, 3 way handshake, flow control and Congestion Control in TCP.
- UDP Protocol uses and comparison with TCP.Which protocols use TCP and UDP.
- Explain DNS, HTTP, HTTPS.
- Explain all the Protocols starting from ARP, RARP, BOOTP, DHCP.
Round 3: FTF Technical Round (45 minutes)
This was an easy round the interviewer asked questions from OS, Data Structures, Puzzles .
- A simple question similar to – https://leetcode.com/problems/guess-number-higher-or-lower/description/.
- A puzzle which goes as – You are in a room with no metal objects except for two iron rods. Only one of them is a magnet. How can you identify which one is a magnet? This was a really good puzzle.
Solution 1: Hang the rods on a string and see which one turns to north.The magnet will align itself with the Earth’s magnetic field and act like a compass, but the unmagnetised bar will not. But this violates the “without using any other substances” requirement.
Solution 2: Magnetic field is strong near the pole of a magnet. So keep one rod(A) on the table and bring the other rod(B) closer towards it. If B gets attracted to one of the ends of A(as field is strongest near the ends) then A is magnet.
- An equation to solve without using hit or trial – 29x + 30y + 31z = 366 . I thought this is the equation of a plane so there will be many solutions but the interviewer told to think in a simple way. This is a really good puzzle. 366 is the no of days in a leap year so no of months with 29 days is 1 (February) and no of months with 30 days is 4 and no of months with 31 days is 7. x=1, y=4, z=7.
- Discussion regarding the projects. Some discussion on topics of OOP and ML like Reinforcement Learning, CNN and SVM, which I had used in the project.
- Some basic Concepts of OOP like Inheritance, Polymorphism, Encapsulation, etc.
- Parameters required when you needed to Predict the floor in which the lift can be present in a multi storey apartment using Machine learning. (like the type of persons living in each floor, facilities in apartment, no of disabled or old persons in each floor etc.)
- Difference between orphan and zombie process and between thread and process? States of a process.
- Design a search typeahead ( Search autocomplete ) system. https://www.interviewbit.com/problems/design-search-typeahead/
eg- for mich it shows michael johnson, michael phelps, michael jordon. I gave him an approach based on trie. He asked me to write the code for insertion and querying in the trie. At every node in the trie I stored the 5 most frequent searches of words having the current string as prefix. Used load balancers for distrubuting the load among multiple application servers ( used Consistent hashing for Load Balancing).
Round 4: HR Round (30 minutes)
Standard HR questions. You should communicate freely without getting tensed. The HR was quiet friendly so we had a nice conversation.
- Tell me about yourself.
- Why do you want to join DE SHAW?
- Why should we hire you?
- Any questions for me(ie for the HR)? I asked about the work culture, office hours, flexible timings, work from home, other facilities in DE Shaw, their clients, etc.
Thanks Geeksforgeeks for being a perfect platform for practice. 🙂
- ServiceNow Interview Experience Oncampus
- MathWorks Interview Experience (EDG, Oncampus)
- UHG Interview Experience | OnCampus- 2019
- InfoEdge Interview Experience | OnCampus-2019
- D E Shaw Interview | Set 3
- D E Shaw Interview | Set 1
- D E Shaw Interview | Set 2
- D E Shaw Interview | Set 7 (Off Campus)
- Interview Experiences at D. E. Shaw & Co.
- D. E. Shaw & Co. Interview Experience
- D. E. Shaw Interview Experience
- D E Shaw Interview | Set 6 (Off-Campus)
- DE Shaw Internship Experience
- D E Shaw Interview Experience | Set 9
- D E Shaw Interview Experience | Set 22 (Off-Campus)
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