A real letdown. Several stages, from coding to system design — all pretty standard stuff. But after sweating through their challenges, all I got was a 'thanks-but-no-thanks' with zero explanation. Despite multiple follow-ups, the team was unable to share detailed insights into the reasons behind their hiring decisions. It felt like a colossal waste of time, as they were there to tick checkboxes, not to listen or engage in a dialogue.

1. First coding interview - Given an array arr[] of non-negative integers and an integer sum, find a subarray that adds to a given sum.

2. Second coding interview - Given an array prices[] of length N, representing the prices of stocks on different days, the task is to find the maximum profit possible by buying and selling stocks on different days when at most one transaction is allowed.

3. System Design interview - The task required developing an in-house analytics system for fraud detection, capable of handling taxi order data storage and analysis. This system should offer APIs for inserting order data and retrieving orders based on the longest and shortest processing times, all while operating without any external database or storage services.