As someone who attempted it, it was such a bad challenge. Firstly you can get close to optimal pretty easily. In first challenge it was easy to exactly solve it in optimal way using DP. Secondly that doesn't matter because the optimal solution has big deviation based on rng. And you just need to submit the challenge multiple times till you get lucky.

That's why challenge problem should take in code and run for hidden cases on their server and reveal the results post contest, not allow it via API call.