2224A - Zhily and Array Operating

2224B - Zhily and Mex and Max

2224C - Zhily and Bracket Swapping

2224D - Zhily and Barknights

2223C - Zhily and Signpost

2223D - Zhily and Cycle

2223E - Zhily and Permutation

2223F - Zhily and Colorful Strings

Nihao! Hello to all fans of competitive programming and Codeforces enjoyers!

On behalf of Tsinghua University’s Zhili College, we — your proud and slightly sleep-deprived Class of 2029 Information and Computational Science students — are happy to invite you to participate in Codeforces Round 1097 (Div. 1, Based on Zhili Cup 2026) and Codeforces Round 1097 (Div. 2, Based on Zhili Cup 2026), which will take place on May/06/2026 09:05 (Moscow time). Note the unusual start time of the round. You’ll have 2.5 hours to tackle 6 problems for both division 1 and division 2, the round will be rated for all participants.

The score distribution will be announced later.

This round’s problems are brought to you by the incredible AC-Automation, graphcity, erduolong, Ge_QingHui, rsrsr, yangyuxi, schrodingerstom, unputdownable, lyreqwq, wangzhifang, aleph1022 and LinRui. Special thank you to thebighead and CharlieV who also prepared problems that were ultimately not used in this round.

A massive THANK YOU to the following legends who made this event possible:

• The one and only KAN for his invaluable support in hosting the round.

• Our chad coordinator, SSerxhs for coordinating this round, finding testers, and providing moral and technical support.

• Our brilliant testers: XiaoXia, Liang_SYEA, fr200110217102, Nanani, Boboge, CReatiQ, triple__a, tarjen, permutation, SATSKY_2025target_LGM, fallleaves01, tiger2005 and turmax for testing and providing invaluable feedback.

• Our fantastic organisers: schrodingerstom, lyreqwq, LitDarkness and kevinliu251831 for the smooth operation of the contest.

• Our advisors Ruidong Wan, Yaqi Zhou, Yike Cao and Xi Wang from Zhili College for supporting our efforts and ensuring school approval.

• Special thanks to Tsinghua University’s Association of Algorithmic Competitions for their support and help.

• MikeMirzayanov and geranazavr555 for enabling this event through the amazing Codeforces platform.

Zhili Cup itself is an annual event hosted by Tsinghua University’s Zhili College along with its freshmen of ICS. We are delighted to meet you on Codeforces this year.

Good luck, and may your code be bug-free and your coffee cup never empty.

See you at the round!

UPD1: Score distribution

• Div. 1: 500−750−1500−2500−3500−4500
• Div. 2: 500−750−1000−1250−2250−3500

UPD2: The editorial has been published.

• https://mirror.codeforces.com/blog/entry/153567