Hello, Codeforces!

We are exited to invite you to participate in Codeforces Round 1124 (Div. 1) and Codeforces Round 1124 (Div. 2) which will be held on Sep/26/2026 17:35 (Moscow time).

The round will be rated for participants from both divisions. You will be given 2 hours and 30 minutes to solve 6 problems for each division.

The problems are authored and prepared by _R00T, eren__, sweetweasel, and me (Hamed_Ghaffari).

We would like to thank:

• Error_Yuan for coordinating the round.
• Um_nik for preliminary reviewing and testing the round.
• AmShZ, N_z__ for red testing.
• AKprinceofpersia, Arpa, Dindin, Mhn_Neek, misteg168, mohammadsam, msab3f, narges__ for orange testing.
• Behesht, Behrad., Qazall, kian2009, rafieefatemeh for purple testing.
• SevenAlarm, Srsh, caibyte for blue testing.
• GUM for cyan testing.
• AlirezaBest for green testing.
• qhj0906 for gray testing.
• Alexdat2000 for Russian translation.
• MikeMirzayanov and KAN for the great platforms.
• You for participating!

The scoring distribution will be added soon.

We hope you enjoy the problems.

Good luck and have fun!

UPD1: The scoring distribution is released:

• Div. 1: $$$500 - 1000 - 1750 - 2250 - 2750 - 3250$$$;
• Div. 2: $$$500 - 1000 - 1500 - 2000 - 2750 - 3250$$$.

UPD2: Editorial

UPD3: Congratulations to the winners!

Div. 1

1. Ormlis

2. tourist

3. Elysion

4. jn_275

5. turmax

Div. 2

1. YerzhanU

2. -Fm2-

3. NiklasPlugin

4. zhude

5. kumod-Kumar

Hello, Codeforces!

We are proud to invite you to participate in Atto Round 1 (Codeforces Round 1041, Div. 1 + Div. 2) which will be held on Aug/07/2025 17:35 (Moscow time).

The round will be rated for everyone. You will be given 8 problems, one of which is divided into two subtasks, and 3 hours to solve them. One of the problems will be interactive, so make sure to read the guide for interactive problems before the contest.

The problems are authored and prepared by Ali_BBN, Bahamin, _R00T, eren__, sweetweasel, and me.

We would like to thank:

• Error_Yuan for his great coordination.
• Alexdat2000 for Russian translation.
• errorgorn, StarSilk for nutella testing.
• _istil, abc864197532, yuanruiqi, [MVP] LMydd0225, A_G, maomao90, AmShZ, N_z__, Keshi, zeemanz for red testing.
• arashmemar, ooscode, A_M_Namdar, radal, mohammadsam, ParsaF, IliyaEslahi for orange testing.
• AlefHeKaaf, Shahrad_Mirzaei, rewhile, Siyah, ParsaS for purple testing.
• theSkeleton, iliya_mon, Kosar, amir_AP, Ardelion, KiaRash24, hamidh100, mathtsai, Behrad. for blue testing.
• FrontMan. for cyan testing.
• MikeMirzayanov and KAN for the great platforms.
• You for participating!

Special thanks to [MVP] LMydd0225 for his invaluable help during testing!

The scoring distribution is below.

Now, a few words from our sponsor!

At Atto Trading, we are a science-driven quantitative trading firm where engineers, quants, and researchers combine their efforts to engineer cutting-edge trading systems that execute in nanoseconds, powering decisions at the speed of light in the world’s most competitive market. Many of our team members started their journey on platforms like Codeforces. We are thrilled to announce our own round on Codeforces platform.

Follow the link below and complete the application form to explore career opportunities with us.

We prepared some exciting rewards for participants in this round.

• Rank 1: Apple MacBook + backpack + branded T‑shirt + sports bag
• Ranks 2-3: Apple iPad + backpack + branded T‑shirt + sports bag
• Ranks 4-5: Apple Watch + backpack + branded T‑shirt + sports bag
• Ranks 6-20: Backpack + branded T‑shirt + sports bag
• Ranks 21-100: Branded T‑shirt + sports bag

If we encounter difficulties delivering your gift, we reserve the right to reimburse its value in cryptocurrency

Good luck!

UPD 1: Score distribution was released!

UPD 2: Editorial

UPD 3: Congratulations to the winners!

1. ksun48

2. jiangly

3. turmax

4. tourist

5. jiangbowen

6. zhoukangyang

7. maspy

8. ecnerwala

9. Radewoosh

10. 244mhq