Hey Geeks, I am writing down my interview experience with DE Shaw. I applied through the carrier portal of DE shaw. I received a test link after more than a month. The total process consisted of 4 rounds(Coding test, Screening Round, On-site-1, and On-site-2).

**Coding Test: **This round consisted of 3 coding problems, 10 MCQ on CS fundamentals, and10 MCQ from Aptitude. I was able to solve the 2 Hard problems of 40 marks each however I was not able to solve the first one.

- The first one was: 2 players play a game with some starting number N. At each step each one will subtract a perfect square from the starting number until it becomes 0. The person playing the last move wins. Predict the winner for a given starting number N. N <= 1e6.
- Second One: https://www.geeksforgeeks.org/bell-numbers-number-of-ways-to-partition-a-set/
- I don’t remember the 3rd one.

MCQs were easy.

**Screening Round:**

- Find max consecutive one.
- Similar to the minimum number of platform problem. But you also need to tell the platform number for each train. You are given an array of [{Train_Number_1, Arrival_time_1, dept_time_1}].
- What is normalization in dbms?
- B-tree vs B+ -tree
- Indexing and Index Table.
- Virtual keyword, Vptr, vtable

**Onsite Round 1:**

- Given an array of binary strings. Find the largest subset of the string such that the max count of zeroes is m and that of ones is n. They made me write the code.
- Related to project.
- Median of a stream on integers. I replied instantaneously so they added a delete number operation to makes things hard only logic was required at this stage no coding.
- Given 3 arrays. A, B, C. Find i, j, k such that A[i] + B[j] = C[k].

No CS fundamentals in this.

**Onsite Round 2:**

Some HR-based questions.

- Very friendly interviewer in this round.
- They asked about the famous browser history problem. They wanted a DS-based. solution. Since I have some development experience I gave them an elegant solution they were a lot impressed with me. He also said excellent.

The second interviewer asked me CS fundamentals and project-related.

- How react.JS works. VDOM.
- How JS being single-threaded performs multithreading.
- Process vs Threads.
- Multithreading vs Multiprocessing.
- CPU intense task vs I/O intense task which will you prefer.
- Some more rapid-fire questions were also there.

This marks the end of the process.

**Verdict: Selected**