Interview Experience in Hashedin by Deloitte

My interview journey with HashedIn by Deloitte began with an Online Assessment. It was a 90-minute test featuring three questions: one easy and two medium LeetCode-type problems. A unique aspect was the absence of automated test cases; I had to meticulously code, devise my own custom test cases, identify edge cases, and then submit my solutions.

Technical Interview - Round 1

The very next day, I was shortlisted for the first technical interview round. It kicked off with an introduction where they inquired about my passions and extracurricular activities. We then delved into core subjects like OOPS, C++, and DBMS. They specifically questioned me on:

• Diamond inheritance in C++
• Types of Joins in SQL
• The concept of a Virtual Constructor
• A SQL query to find the second largest element in a table

Following this, I tackled coding questions. The panel consisted of two interviewers, though one was more active. I was asked to write code on paper, but a clear logical explanation was also acceptable. My first coding challenge was a variation of the Longest Palindromic Subsequence problem: given a string, I had to reverse it and find the Longest Common Subsequence (LCS), a common approach from the LeetCode Striver Sheet. After finding an optimal solution for that, they posed a trickier follow-up: finding the second largest palindromic subsequence. This took me some time, and I needed hints, but I eventually arrived at a solution, albeit not the most optimal one. I also solved another DP question involving array partition.

Technical Interview - Round 2

The second technical round started with some fundamental coding questions:

• Detecting a Cycle in a Linked List, where I discussed the Hare and Tortoise method.
• Implementing a Stack using a Queue.

Next was a substantial System Design challenge. I was tasked with designing a high-level application similar to Flipkart, incorporating specific features they outlined. I drew out API call flow diagrams and designed a database schema, complete with foreign key references. They then guided me through normalizing the database, and while I made progress, I couldn't entirely complete it to their exact specifications. Finally, they gave me a SQL query based on the tables I had just designed.

HR Round

The HR round was quite relaxed. We discussed projects from my resume, including my motivations for building them and their technical details. They also asked casual questions, such as my preference between CR7 and Messi, my family background, and personal interests. A memorable situational question was, "What would you do if you received ₹10 crore today?" My understanding is that if you reach the HR round at HashedIn, selection is highly probable, as they selected everyone who made it to this stage.