Kotak Mahindra Bank

Role: SDE-1

College: Not Specified

Interview Date: February 2024

Interview Type: Full-Time (Applied through referral)

Result: Rejected

Difficulty: Medium

Rounds: 3 Technical Rounds

Topics Asked: Data Structures, Algorithms, System Design (LLD), CS Fundamentals, Java, Microservices, Database, API, HashMap, Immutable Class, Method Overloading/Overriding, Inheritance, OOPS

Experience:

The candidate applied through a referral. HR discussed current CTC, tech stack, and reason for switching, offering an SDE-1 role due to less experience for SDE-2. HR explained the process: 3 technical rounds (Bar Raiser, Coding, LLD), with the Bar Raiser focusing on DSA and CS fundamentals.

Technical Round 1 (Bar Raiser - 1.5 hr): Conducted by a senior developer (8 YOE). The interviewer stated they would ask 1 DSA problem and 1 Design problem, giving 45 minutes to each. The candidate was surprised by the design problem in this round.

• DSA Problem: Merge Intervals (LeetCode Medium). The candidate explained the approach, coded the solution on an IDE, and discussed time and space complexity.
• Design Problem: Designing a cab booking service similar to OLA/Uber. The interviewer was interested in API and DB designs, not coding. The candidate explained the flow, designed APIs, and discussed the DB Schema (SQL database, ACID properties).

The interviewer was kind and provided ample time.

Technical Round 2 (Coding - 1 hr): The interviewer was an SDE 3 from Kotak. The round started with an in-depth discussion (20-25 minutes) on the candidate's previous project, focusing on Microservices, Database, and API, as the interviewer had a Java and Spring background.

After project discussion, Java-specific questions were asked:

• Implementation of HashMap in Java Collections framework, including collisions and loading factor.
• How to make a class immutable (using the `final` keyword).
• Difference between method overloading and overriding.
• Inheritance.

The candidate was also asked to code a problem related to an array, which they solved with O(n) time complexity. The interviewer asked for further optimization, and the candidate explained an O(log n) approach using binary search, but time ran out.

Technical Round 3 (LLD): Not much detail was provided for this round in the combined sources, but it was mentioned as part of the HR-explained process.