We, HACKARZ, are glad to invite you to participate in HFC #4, which will take place on 28.06.2025 18:00 (Московское время). You will be given 8 problems and 2 hours to solve them. The problems ARE NOT SORTED ACCORDING TO DIFFICULTY so please read the full problem set.
The problems were authored & prepared by: Ahmed_Salamaa, .Habiba., MohammadAbduljalil, ahmedfouadnew, Youssef_Elwazzan, Hamed5001, and the coordinator, me (Since Ahmadsm2005 is busy).
We had testers from all over the Arab region, from Morocco in the west to Palestine & Syria in the east.
We would like to thank FTS_Problem_C, benjellounelghali99, Magician_Mathematician, plankk, Metal_Sonic, Mohanad_Nahhal, NourWaelAli, Rayo, and Wawi for testing.
Special thanks to yahia, who tested and played a big role in the contest preparation to make it better.
We would like to thank our media team for their efforts — especially the leader enfp, who did a great job.
We would like to thank Maqed for his technical support in the custom standings.
Join the group: https://mirror.codeforces.com/group/zJtqriSgdw/contests.
IMPORTANT NOTES:
- Solving some problems may depend on reading others.
- Searching for anything is allowed during the contest, but using AI like ChatGPT is not allowed.









I hope you enjoy the contest, especially the art :D
Excited!
Can we do team for this one?
Unfortunately, the contest problems aren't designed to be solved with a team, but we will consider this idea in the next rounds, inshallah.
Nice i Really looking some contests.
I hope to solve at least 2 problems. Excited!!
Hi how can i join?
You can join the group through the link provided in the blog, and then u can register in the contest. Enjoy <3.
I think you've to generate invitation link
UPD : I see