As a feedback, I think the limit of 100 submissions a day was way too high. On the last day of the competition, I was basically fine-tuning my algorithms using the online test set as a validation set. This might also be the case for the other top 3 participants who also made a lot of submissions during the last day.
This is not satisfactory:
_for the organizers, the fine-tuned algortihms might overfit the online test set;
_for the participants, this incentivize them to perform a boring task (fine-tune using the online test set as a validation set) till the very end of the competition. With a limit of only 5 submissions, I would have done my 5 submissions and do something else of my day. But, here, the possibility to submit as many files as I want pushed me to fully use this so I would regret nothing.
For the next round, I think a hidden test set would be the best, if not possible a limit of 5 submissions per day would be good.
This is just my humble opinion, this was my first competition and maybe other participants feel different about it.
PS: That being said, I enjoyed participating this competition and I would like to thank all the people organizing and participating this competition, the final was tense/exciting and I learned a lot about multi-lateration!