Squarepoint

Role: Software Engineer (Campus Placement)

College: IIT BHU

Interview Date: October - November 2024

Interview Type: On-Campus/Full-Time

Result: Not Selected

Difficulty: Hard ("rigorous", "they don't want even a small ounce of mistake")

Rounds: Online Test + 3 Interview Rounds

Topics Asked: Data Structures, Algorithms, C++, Operating Systems, Computer Networks, Multithreading, Parallel Programming, Python, Debugging.

Experience:

This candidate from IIT BHU interviewed for Squarepoint Capital during campus placements. The process consisted of two stages: an online test and three interview rounds.

Stage 1: Online Test

The online test featured two medium-difficulty questions. One involved a 2-pointer approach with a condition, and the other was related to stock prices, requiring the removal of overlapping cost ranges and maintaining prices. The candidate successfully cleared this stage.

Stage 2: Interview Rounds

Round 1 (Technical - C++, OS, CN, DSA): Scheduled on October 22. The interviewer began with an introduction, then asked about C++17 features not present in C++14, specifically structural bindings, which the candidate demonstrated by iterating a map of pair and int. Questions delved into the implementation of map data structure using balanced binary search trees (AVL tree explanation and pseudocode). Deep C++ and OS questions were asked, including differences between semaphore and locks, race conditions, critical sections, different types of casting (static, dynamic, reinterpret), program lifecycle, and memory allocation for static and dynamic variables. A DSA question involved finding the best currency conversion path given exchange rates, which the candidate solved as a graph problem using Dijkstra's algorithm, emphasizing design-level code with proper classes and OOP concepts. The round concluded with Computer Network questions on TCP/IP and differences between Virtual Circuits and Datagram service.

Round 2 (Technical - Projects, Python, DSA): Scheduled on November 11. This round was with a British interviewer who was described as "chill and friendly." The interviewer grilled the candidate on their internship project, requiring a deep dive into the work done. Following this, basic to intermediate Python questions were asked, including list comprehension, generators, and GIL, which the candidate coded to the interviewer's satisfaction. Two DSA questions were given: one standard Priority Queue (PQ) question and another on Digit DP, both of which the candidate solved with all test cases passed. The interviewer then asked questions about projects related to multithreading and parallel programming.

Round 3 (Technical - Debugging, System Design): This was considered the "most tricky round." Instead of a typical DSA question, the interviewer provided a complex C++ code snippet to debug. The code focused on maintaining a critical section without deadlocks. The challenge was to reduce the latency of a queue class within the provided code, which was observed to be using locks inefficiently without proper notification conditions. The candidate identified that locks were releasing only when the state came again, rather than when the task was done.

Result: The candidate was not selected despite "outperforming so great throughout the process," attributing it to "one small mistake," highlighting Squarepoint's high standards.