The process began with an online coding round where I was tested on data structures and algorithms.

After clearing that, I was shortlisted for the technical interview. In this round, the interviewer asked me two coding questions:

1. Flatten a Linked List – I had to implement a function to merge all the sub-lists into one sorted list using recursion.

2. Minimum Platforms for Trains – This was a greedy problem involving sorting arrival and departure times to calculate the minimum platforms required.

I explained my approach, wrote the code in C++, and discussed the time complexities.

I could not proceed further to the HR round, but the experience was very insightful and helped me understand the type of problems asked in product-based company interviews.

1. Flatten a Linked List

I was given a special linked list where each node had two pointers: next (to the right) and bottom (downwards).

Each bottom list was already sorted.

The task was to “flatten” this structure into one single sorted linked list using the bottom pointers only.

This tested my knowledge of recursion, merging sorted lists, and pointer manipulation.

1. Minimum Platforms Required for Trains

I was given N trains with arrival and departure times.

The problem was to calculate the minimum number of platforms required so that no train waits at the station.

The key was to sort the times and use a greedy/two-pointer approach to track trains on the station at the same time.