Hello, Codeforces!

This Sunday there will be a Moscow Olympiad for Young Students. This contest is prepared by Moscow Olympiad Scientific Committee that you may know by Moscow Open Olympiad, Moscow Team Olympiad, Metropolises Olympiad and All-Russian olympiad in the name of Keldysh.

We are glad to invite you to Codeforces Round 1078 (Div. 2) based on the problems of this olympiad, which will take place on Feb/08/2026 12:05 (Moscow time). Note the unusual time of the round. The round will be held according to the Codeforces rules and will be rated for all participants with rating below 2100.

Problems of this competition were prepared by silvvasil, Semen07, allvik66, dope, teraqqq guided by TheEvilBird, grphil and Helen Andreeva.

Thanks to FairyWinx for the round coordination, and also thanks for MikeMirzayanov и KAN for Codeforces and Polygon platforms, which was used to prepare problems of this olympiad.

We also thank:

• t.ravnushkin, KiKoS, didedoshka, feblokas, makrav, blook, zhiganov_v, lewc, gmusya for testing the main Olympiad problems;

• __baozii__, _istil, ArSarapkin, fishy15, PvPro, madlogic, -firefly- for testing the round;

• RP-1, stepanov.aa for the preparing Olympiad problems that were not included in the round.

The scoring will be available later.

Greetings Codeforces community!

We are excited to announce the Constructor Open Cup 2026, our annual online programming competition organized by Constructor University and JetBrains Foundation.

What is the Constructor Open Cup?

Constructor Open Cup is an online contest organized by Constructor University and JetBrains Foundation to promote interest in computer science, data science, software development, and software engineering.

Put your knowledge and skills to the test in this 4-hour competition and stand a chance to walk away with a scholarship for a bachelor's degree in Software, Data and Technology (BSc SDT) at Constructor University, Germany’s #1 private university*!

Constructor Open Cup timetable

February 2 — February 12, 2026 | Practice Round

Get familiar with the testing environment during this practice round.

February 12, 2026 at 2 PM (UTC) | Main Round

You will have 4 hours to complete a series of algorithmic programming tasks. Registration closes 1 hour before the start of the contest.

Winner announcement

The top candidates aiming to study for a bachelor’s degree will have a chance to get scholarships* for the BSc SDT program by Constructor University and JetBrains Foundation.

*The winners who applied to the BSc SDT will receive an email to schedule the interview with Constructor University and JetBrains Foundation.

How can I participate?

• Register your details on the webpage.
• Finalize your registration at Codeforces using the link you receive in the confirmation email.
• If you have any further queries, please reach out to [email protected].

How can I prepare?

Prepare for the Constructor Open Cup 2026 with an online editorial where our expert goes over the problems from last year’s competition and shares helpful tips. The editorial is available here.

What do participants say?

“I was just surfing Codeforces blogs when I found a post about the Constructor Open Cup 2023. After discovering that I could have a chance to win a scholarship from JetBrains, I registered for the competition and placed among the top 20-30. The contest itself was very interesting, with different types of problems that allowed me to showcase my knowledge. I felt very honoured to receive a scholarship, and now I am one of the students in the BSc SDT program” – IMRUN, BSc SDT second-year student.

Can I participate?

Everyone is welcome! The contest is open for all ages and skill levels, all you need is a passion for coding. To get the chance for the scholarship for BSc SDT, please check Constructor University’s eligibility requirements.

About the BSc SDT program

The BSc Software, Data and Technology (SDT) program is an innovative and unparalleled way to jumpstart a career in the rapidly growing fields of software, data and technology. The program is crafted in partnership with JetBrains Foundation, a non-profit organization within the JetBrains group – a global software company. Not only will you learn the latest technologies, but you will also be ready to hit the ground running as soon as you graduate.

With a BSc in Software, Data and Technology, graduates will be well-equipped to pursue a variety of career paths, including data scientist, software engineer, full-stack developer, analytics expert, data mining specialist, network security analyst, artificial intelligence engineer, and more. This program is ideal for students who are passionate about using technology to solve real-world problems and make a meaningful impact in the world.

Enrolling in the SDT program will be a smart investment for your future and will open doors to a wide range of career opportunities in software, data and technology.

Hello, Codeforces!

After years of hard work, we are euphoric to invite you to participate in Codeforces Round 1077 (Div. 1) and Codeforces Round 1077 (Div. 2), which will be held at Jan/29/2026 17:35 (Moscow time). For both divisions, you will be given $$$7$$$ problems and $$$3$$$ hours to solve them. For at least one of the divisions, one of the problems will be divided into two subtasks.

The problems are invented and prepared by Bronya_H, Error_Yuan, StarSilk, Tobo, __baozii__ and me.

We would like to thank:

• SSerxhs for his Superb, Stellar, Extraordinary, Reliable, Xcellent, Helpful and Supportive coordination.
• Alexdat2000 for Russian translations.
• zeemanz and bookcat for providing some ideas that were not ultimately used.
• cry for inventing a basement of infinite capacity to imprison cheaters.
• errorgorn, tiger2005, EnofTaiPeople, and dXqwq for black opal testing.
• geospiza, Aging1986, Sugar_fan, Duck_sajin, qkm66666, AYTDD, Fantasy_Blue, Intellegent, SATSKY_2025target_LGM, _istil, wangmarui, rucaco, fallleaves01, permutation, nifeshe, and A_G for ruby testing.
• Proof_by_QED, sh1ziku, 0x3F, K_tian, aori., sszcdjr, hxu10, CirnoNine, and chennie for topaz testing.
• fatalerror, Fusu, -WIDA-, shendeliliang, and Liang_SYEA for amethyst testing.
• Kato_Shoko, TEYL, clearlove13, Non-origination, chromate00, fr200110217102, and XiaoXia for sapphire testing.
• imhighshou and Clclclcl for aquamarine testing.
• MikeMirzayanov for his obsidian Codeforces and Polygon platform.

The score distribution is below.

Div. 1: $$$750 - 1250 - 1750 - 2000 - 2250 - (2000 + 3500) - 3000$$$.

Div. 2: $$$500 - 1000 - 1500 - 2000 - 2500 - 2750 - 3000$$$.

We sincerely hope you can enjoy the problems. Good luck and see you on the field !

UPD1: The hacks are disabled for problems A-D in Div 2, and for problems A-B in Div 1. We have final tests consisting of pretests and hacks for all problems.

UPD2: Editorial

Hello, Codeforces!

We are glad and excited to invite you to take part in Codeforces Round 1076 (Div. 3), which will take place on Jan/25/2026 17:35 (Moscow time). You will be given 2 hours and 15 minutes to solve 7-8 probmles. At least one problem will be interactive, so we highly recommend to read guide for interactive problems before the contest.

The round will be hosted by the rules of educational rounds (extended ICPC). Thus, all solutions will be judged on preliminary tests during the round, and after the round, there will be a 12-hour phase of open hacks. After the open hack phase, all accepted solutions will be rejudged on successful hacks.

As a reminder, only trusted participants of the third division will be included in the official standings table. This is a compulsory measure for combating unsporting behavior. To qualify as a trusted participant of the third division, you must:

• take part in (and solve at least one problem in) at least five rated rounds
• and not have had a rating of 1900 or higher at any moment in time.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you (unless you register unrated).

Problems were authored by KluydQ, YF_YUSUF, Wansur, Mendeke.

We would like to give special thanks to:

• Vladosiya and soullless for the great coordination and chance to host this contest.
• Wansur, k1r1t0, Arpa, Aldk, SorahISA, QazLon, itz_pabloo, YF_YUSUF, Daki-sa, Yessimkhan, Arkanefury, hamburger46, gbula, China001, Dobri_oke, Idam, wadibay, Darko, uwbt17, raiywbek, CLown1331 for their time and effort in testing.
• MikeMirzayanov and KAN for the great Codeforces and Polygon platforms.

UPD: Editorial is here

Hello, Codeforces!

We are excited and pleased to announce that Codeforces Round 1075 (Div. 2) will be held on Jan/23/2026 17:35 (Moscow time). This round will be rated for all participants with rating below $$$2100$$$. You will be given $$$2$$$ hours to solve $$$6$$$ problems and some problems will be divided into subtasks.

The round is based on the Sharygin International Geometry Olympiad All problems were authored and prepared by yanb0, furt1ve and me.

We would like to express our special thanks to:

• Akulyat for coordinating the round and assistance in preparing problems;
• the testers: Wansur, __baozii__, k1r1t0, Mark_Pr, _istil, OG_Matveychick1, TimDee, zhenja, abs0lute, princeee, NotDWT, Sokol080808, machine_solution, Pobe, madlogic, wuhudsm, pattern-seeker, dvb1r, VitaliiV, penwick, sanya37y, itz_pabloo, Morselllprimo, AK_15, Golden_Square, Norman165, arsen1y, graphs_enjoyer, tih-a, emirhanbanan, ak1ko, s97b, thereverberation, bibiq for their time and effort in testing the problems;
• MikeMirzayanov and KAN for the great platforms.

The score distribution is below.

$$$500-1000-(1250+750)-(2000+750)-2500-3250$$$

GLHF!

UPD1 The round is over, thank you for participation.

UPD2 Editorial

UPD3 Winners and First to solve

Div2

Div1 + Div2

First to solve

The Registration for the 50th Petrozavodsk Programming Camp is open.

THE CAMP WILL BE HELD ONLINE from January 29 to February 06, 2026.

For teams from the EAEU, offline participation is possible; details are in the information letter.

Teams of up to 3 members are invited to join

The level of contests: for participants of the semi-finals and finals of the ICPC World Championship

The training Camp schedule consists of 8 contests and 1 day off between them, preliminary schedule: camp.icpc.petrsu.ru/2026w/schedule

For each contest, a problem analysis will be broadcast in English.

The registration fee for participants from the EAEU countries is 12200 / 13420 / 24400 rubles per participant (depends on meal inclusion).
The registration fee for participants from other countries is $165 per participant.

To register, the team coach should write a letter to the organizers.
After agreement, each team member must go through individual registration on the site of the Camp.

Contact Information

• Contact the organizers: [email protected]
  
• Website: camp.icpc.petrsu.ru
  
• Group in VK: vk.com/camp_acm_petrsu
  

Hello Codeforces!

I am delighted to invite you to the first Div. 4 round of the year: Codeforces Round 1074 (Div. 4)! The round is scheduled for Jan/18/2026 17:35 (Moscow time). You will be given 7 — 8 problems to solve (all authored by me), and 2 hours and 15 minutes to solve them.

The format of the event will be identical to Div. 3 rounds:

• ICPC rules with a penalty of 10 minutes for an incorrect submission.

• 12-hour phase of open hacks after the end of the round (hacks do not give additional points).

• After the end of the open hacking phase, all solutions will be tested on the updated set of tests, and the ratings will be recalculated.

Only trusted participants of the fourth division will be shown in the official standings. To be a trusted participant, you must:

• have participated in at least 5 rated rounds where you have solved at least one problem.

• have a rating less than 1400.

Regardless of if you are a trusted participant or not, this round will be rated for you if you

• have a rating of less than 1400 or are unrated.

• do not select the "Register as unrated" option when registering for the contest.

Participants who are rated 1400+ are not allowed to create a new account for the purpose of competing officially. We encourage you to take part unofficially.

We would like to remind all participants about the rule against using artificial intelligence tools during the contest. Violators will be sent to cry's basement; we spent a long time expanding it so we could host this round, and we sincerely hope that it won't be filled back up again.

I would like to thank:

• cry for being an incredible coordinator, and for giving me a chance to write this contest.

• Vladosiya for translating the problems into Russian.

• cduckling for looking over the initial problemset before I officially proposed it.

• Our red testers: __baozii__, Intellegent

• Our golden testers: Arpa, -firefly-, AksLolCoding, Edeeva, Friedrich, omsincoconut, Proof_by_QED, temporary1

• Our purple testers: macaquedev, pop, tin.le2, wuhudsm

• Our blue testers: apollo07, Argentum47, Eikyu, Ermiooo159, expertaq, Jteh, ritam1234, simplelife, SpyrosAliv, susvent, Vladosiya

• Our cyan tester: anandswaroop191

• Our gray testers: DraxLab, piman51277

• Our unrated tester: qdread

• MikeMirzayanov for creating Codeforces, Polygon, and testlib.h.

• You, for participating!

I wish you all the best of luck in this competition, and I hope you enjoy the problems!

EDITORIAL.

Hello Codeforces,

After decades of hard work and several quality reviews from independent third parties, I'm delighted to invite you to participate in Codeforces Round 1073 (Div. 1), and, if you really want to, Codeforces Round 1073 (Div. 2), which will both held on Jan/17/2026 17:35 (Moscow time).

In each division, you will be given $$$7$$$ problems and $$$3$$$ hours to solve them, one of which will be divided into subtasks. Problems were mainly authored by me, nifeshe, with help from nika-skybytska and satyam343. Only $$$6$$$ or $$$7$$$ problems will not be interactive in each division, so please make sure to read the guide for interactive problems before the contest.

In related news, we’ve already been awarded the Nobel Peace Prize for this round, for achieving a level of problem quality so universally accepted that all global conflicts have been resolved.

I would like to thank the following people for making the contest possible:

• satyam343 for outstanding coordination and helping with problem ideas/preparation.
• Um_nik for preliminary reviewing the round.
• Sana for being the most helpful tester I've ever seen.
• EvenImage, Geothermal, A_G, sammyuri, _istil, Intellegent, catgirl, Dragos, weirdflexbutok, Hori, samsoom, whiitex for VIP testing.
• The rest of our testers: LipArcanjo, Adam_GS, __baozii__, jiazhichen844, maomao90, IceKnight1093, wangmarui, caterpillow, -firefly-, arvindr9, djm03178, omsincoconut, CatsAreCool, reirugan, conjectureguy, SpyrosAliv, chromate00, Non-origination, beaten_by_ai.
• Alexdat2000 for translating the problems to Russian.
• MikeMirzayanov and KAN for the Codeforces and Polygon platforms.
• And You for participating!

The score distribution is below.

Div. 1:

Div. 2:

Unlike other rounds, this one will only be held once, so I sincerely hope you will not skip the round and enjoy all of the problems.

UPD 1 The hacks are disabled for problems A — D2 in Div 2, and for problems A — B2 in Div 1. We have final tests consisting of pretests and hacks for all problems.

UPD 2 Editorial

UPD 3

Congratulations to the winners.

Div. 1:

1. Petr
2. strapple
3. jiangly
4. tourist
5. Radewoosh

Div. 2 (subject to change):

1. LHNB
2. xoxoKitty
3. EchidnaTea
4. AuroraUwU
5. t1e1

First solves:

Div. 1:
A. 00:02:15 by TKT_YI
B1. 00:08:23 by Petr
B2. 00:14:54 by strapple
C. 00:35:39 by jiangly
D. 00:21:27 by PCTprobability
E. 01:42:55 by XVIII
F. 02:53:16 by olmrgcsi
G. 01:34:40 by rainboy

Div. 2 (subject to change):
A. 00:01:21 by akshW
B. 00:05:49 by khushicodes03
C. 00:10:28 by ansh91627
D1. 00:12:47 by CoderMeow
D2. 00:18:11 by sks4401
E. 00:54:52 by crimson_leaf
F. 00:47:03 by shobhitgagrani.coding33
G. 02:54:37 by dooglius

Hello, Codeforces!

The TG channel team @KogutIvanTutoring is pleased to invite you to participate in the first Div. 3 round of this year — Codeforces Round 1072 (Div. 3) on Jan/12/2026 17:35 (Moscow time). This round will feature 6-7 problems selected in difficulty to create an interesting competition for participants with ratings up to 1600. However, anyone with a rating of 1600 or higher can register for the round out of competition.

The round will follow the rules of educational rounds. Thus, during the round, the problems will be tested on preliminary tests, and after the round, there will be a 12-hour phase of open hacking. After this phase, all successful attempts will be retested on successful hacks. We have tried to create decent tests — just like you, we will be disappointed if many solutions fail after the contest ends.

You will be offered 6-7 problems and 2 hours 15 minutes to solve them.

The penalty for an incorrect attempt in this round will be 10 minutes.

We remind you that only reliable participants of the third division will be included in the official results table. As stated in the link — this is a necessary measure to combat unsportsmanlike behavior. To qualify as a reliable participant of the third division, you must:

• participate in at least five rated rounds (and solve at least one problem in each of them)
• not have a rating point of 1900 or higher.

Regardless of whether you are a reliable participant of the third division or not, if your rating is below 1600, the round will be rated for you.

The problems were conceived and prepared by part of our team: fstilus, Friendiks, gravitsapa, EzikBro, Boodoochai

Also, a big thank you to:

• MikeMirzayanov for the Polygon and Codeforces systems.

• Vladosiya for coordinating the round.

• misha.arkhipov, Escapisst, feblokas, lewc, mlovbnee, Yassia, YamOCHca, -_TIMOFEY_-, _liravel_, Gmacem, vintermach, margothequeen, itz_pabloo, sivukhin, Merkurev, the_dragon_emperor, Cyber, MariamH, Arpa, Marckess for testing of the round.

Good luck to everyone!

UPD. Editorial is out!