Here's an official tutorial which was shared during the MW camp: https://drive.google.com/file/d/1jDmzubw6AtzBFvQZjeFLef4OM9Nx-DLQ

BTW it should be XXII instead of XVII xD

Wow, some teams managed to get everything accepted? Respect. I participated in it virtually with Marcin_smu. mnbvmar participated in it alone and our both teams managed to get 11 AC and were nowhere close to get any of B and M. However I still have that brag that I solved A as my first problem at 0:35 which is ~3 times faster than anybody on Opencup xD. Btw K seemed to be easier for participants of original contest, first AC there was at ~20 minutes and it took mnbvmar 8 minutes (i.e. accepted at 0:10 after 2 minutes for H). However it was too hard for me and after some failed attempts at it I switched to A, which was instant xD (but yeah, yeah, I managed to solve K after some time :P...)