CoinSwitch | SDE 1 | Interview Experience
Summary
I applied for the SDE 1 role at CoinSwitch Kuber via LinkedIn and successfully cleared an online assessment followed by two interview rounds, ultimately receiving an offer.
Full Experience
I applied for the SDE 1 position at CoinSwitch Kuber after seeing a posting on LinkedIn. Shortly after applying, I received a link to complete a Hackerearth Online Assessment. This assessment included three medium-hard questions: one based on Dijkstra's Shortest Path Algorithm, another on Tree Traversal, and a third one that I couldn't recall. I managed to complete the first question and partially complete the second.
A few days later, a recruiter contacted me, informing me that there would only be two interview rounds: one focused on Data Structures & Algorithms (DSA) and one HR round.
My Round 1 (Problem Solving) lasted for 1 hour. We discussed two main problems:
- The first question involved a grid of
m*nsize, and I had to calculate the number of ways to move from the top-left corner to the bottom-right corner, only being allowed to move down and right. This was a straightforward Dynamic Programming problem. - The second problem presented a sorted array containing both negative and positive numbers. The task was to square all the numbers and return them in a sorted format. For example, given
[-5, -3, 0, 1, 4], the expected output was[0, 1, 9, 16, 25]. I first proposed a brute-force solution involving squaring all numbers and then sorting the array, which would have anO(n log n)complexity. The interviewer prompted me for a more optimized solution. I then suggested an approach where I stored negative and positive numbers in separate arrays, squared them individually, and then merged these two already sorted lists, achievingO(n)complexity. They pushed for even further optimization to use constant space, and while I was able to explain the approach using binary search and a two-pointer technique, there wasn't enough time to implement it. They seemed content with my approach.
Next was Round 2 (HR Round), which lasted for 30 minutes. This round primarily involved discussions about my current company and the projects I had worked on. I had to explain my projects in considerable detail. Additionally, I was asked to explain the database systems used by Google Sheets.
A few days following the interviews, I was extended an offer.
Interview Questions (3)
Given a grid of m*n size, calculate the number of ways to move from the top-left corner to the bottom-right corner if you can only move in down and right directions.
Given a sorted array of negative and positive numbers, square all of them and give the output in sorted format.
Example: input [-5, -3, 0, 1, 4], Expected output [0, 1, 9, 16, 25].
Explain the database systems used by Google Sheets.
Preparation Tips
My preparation involved rigorous practice of coding problems, particularly focusing on Data Structures & Algorithms. I brushed up on algorithms like Dijkstra's, tree traversals, dynamic programming, and various array manipulation techniques. I also prepared for discussions about my past projects and common HR-related questions, alongside system design concepts like database systems used in large-scale applications.