MakeMyTrip | SDE 2 | Gurgaon | March 2021 {Reject}

I received a call from a recruiter regarding an SDE 2 opening at MakeMyTrip in Gurgaon.

First Round:

The first round focused heavily on Java. The interviewer asked about my comfort level with Java and then dove into basic questions like 'Why is main declared as static?'. Since I mentioned using Java 8, we discussed new features such as lambdas, why they're useful, the Stream API, and collectors. I was also asked to write a program to calculate the sum of numbers in an array using Java. The interviewer was clearly a Java enthusiast!

Following the Java questions, we moved to data structures and algorithms. I was given two problems:

1. Next Greater Element
2. Modify an array into zig-zag order. For example, given {19, 27, 32, 43, 5, 6}, transform it to {27, 19, 43, 5, 32, 6}.

I was able to solve both questions easily, which allowed me to proceed to the next round.

Second Round:

This round focused more on design.

1. The first problem was to design a Multi-level Parking Lot, starting with Low-Level Design (LLD) and then moving to High-Level Design (HLD). We delved deep into classes and database schema, with the interviewer asking many follow-up questions. This round felt average; the interviewer seemed to be in a rush and was looking for on-the-spot solutions rather than a detailed explanation of my thought process.
2. Next, I was given a problem from a cricket match scenario: 'Given a target to chase, while you can score only 1s or 2s, count how many ways are there with which you can chase the target.' This is a classic Staircase Problem variant. I explained both a recursive and a dynamic programming solution thoroughly.
3. The final question was to design an LRU-LFU cache. The eviction policy was specific: first, choose the least frequently used element, but if there are multiple with the same minimum frequency, then choose the least recently used one. I explained the LLD well, but struggled a bit with the HLD, particularly the database schema. I initially thought of using multiple tables, but the interviewer later pointed out that it could be done with a single table (key, value, frequency, last accessed at).

After this round, HR informed me that I was rejected, primarily due to the design aspects of the second round.