I was sent an interview coding challenge. It was a HackerRank challenge, and I completed it fully; all tests were passing, and all checks were completed.

I submitted the challenge and then waited for a response after sending a submission email.

One week passed, and I sent another reminder email looking for a response. Another week passed with yet another reminder email. I didn't want to be seen as unresponsive, so I followed it up.

However, the person responsible for my interview never returned any of my emails. I assume what I received was just a simple automated email including all the instructions for my challenge. I asked a question and sent multiple emails for the results. Nothing!

Then, two weeks later, I found out I was rejected for an unknown reason. There was no explanation, nothing, not even a response email. I even doubt they found time to check if I completed the challenge at all. What a poor process.

Finding suspicious transactions in a list of transactions.

Different users are gifting books to other users. Who gifts whom is determined via a matrix and likely requires a depth-first search.