| # | User | Rating |
|---|---|---|
| 1 | Benq | 3857 |
| 2 | jiangly | 3810 |
| 3 | maroonrk | 3534 |
| 4 | tourist | 3528 |
| 5 | Kevin114514 | 3510 |
| 6 | turmax | 3411 |
| 7 | Um_nik | 3387 |
| 8 | Radewoosh | 3367 |
| 9 | heuristica | 3322 |
| 10 | strapple | 3317 |
| # | User | Contrib. |
|---|---|---|
| 1 | Qingyu | 157 |
| 2 | maspy | 150 |
| 3 | Um_nik | 145 |
| 4 | Errichto | 139 |
| 5 | adamant | 136 |
| 6 | maroonrk | 134 |
| 7 | nik_exists | 133 |
| 7 | DNR | 133 |
| 9 | AmShZ | 130 |
| 10 | Dominater069 | 129 |
After Codeforces Round 1116 (Div. 1), LLI_E_P_JI_O_K, ranking $$$6$$$, has finally reached the title of Legendary Grandmaster! (Maybe he will be ranked even higher after the cheaters are removed).
All the long years of practice have finally paid off. I hope he inspires everyone in CF community, proving that nothing is impossible if you put in hard work.
Update (5/8):
The Finals Round has concluded (here are links to gym & editorial). Editorials and problems for Qualification Round 1 and Qualification Round 2 are in the gym. Congratulations to all of our finalists!
Please join our Discord server here for the latest information!
Hello Codeforces!
We (SHZhang, antontrygubO_o, JohnVictor, duality, awang11, 79brue, codetiger927, bensonlzl, popkarsd, flamestorm, ETK., GideonB, kingofpineapples, czhang2718, rqi, eyangch, xGaz_), current students at MIT (and me), are excited to announce our new contest — the MIT Informatics Tournament 2025 Spring Invitational!
The invitational will consist of three individual contests: two Qualification Rounds and one Final Round. The top 400 from Qualification Round 1 will qualify to Qualification Round 2.
Qualification Round 1: 11am-1pm ET on April 6th.
Qualification Round 2: 6:30pm-9pm ET on April 12th.
For the Qualification Rounds, we expect a difficulty distribution roughly ranging from Div. 2 A to Div. 1 E.
The top 16 US and top 8 international contestants will qualify for the Final Round on May 3rd. The day of the Final Round is filled with exciting activities such as fun tours around Boston, a fancy banquet, exclusive meets with our sponsors, and solving super cool (and hard) problems! We will give capped reimbursements for travel and lodging.
Registration is open at https://mitit.org/Registration, and we have started reviewing and accepting participants. For more information, check out our website.
Update 2: The Qualification Round has officially concluded! A huge thank you to our contestants for joining us and supporting this new initiative! Congratulations to the top 16 finalists who are advancing to the finals round (along with many more as we continue to confirm people's availability)!
At this time, the scoreboard has been finalized, and you can upsolve our problems / watch our video tutorials with the following links:
Thank you for tuning into our contest! We hope to see you again at our Winter Contest next year~
Update: There is .35 HOURS LEFT before the qualification round. Submit your applications NOW so that they can be reviewed in time!
Please join our Discord server here for the latest information!
Hello Codeforces!
We (duality, antontrygubO_o, SHZhang, rqi, Tlatoani, enoone, codetiger927, czhang2718, bensonlzl, awang11, keta_tsimakuridze, kingofpineapples, SuperJ6, flamestorm ), current students at MIT, are excited to announce our new contest — the MIT Informatics Tournament, M(IT)^2, 2024 Spring Invitational!
The contest will consist of two rounds: the Qualification Round and Final Round. The Qualification Round is an online two-hour individual contest that will take place from 1:00 — 3:00 PM ET on April 21st. We expect a difficulty distribution roughly ranging from Div. 2 A to Div. 1 E. We will offer the top three Qualification Round contestants monetary prizes. See the logistics page for more details.
The top 16 contestants will then be flown to MIT (we will cover all expenses and lodging), where they will compete in the Final Round on May 11th. The day of the Final Round is filled with exciting activities, such as fun tours around Boston, a fancy banquet, exclusive meets with our sponsors, and solving super cool (and hard) problems!
Note that due to logistical constraints, we can only fly contestants within the USA to MIT unless they arrange their own transportation and travel logistics. However, top internationals are still eligible for prizes in the Qualification Round.
For more information, check out our website, and the registration application is now open on a first-come-first-serve basis!
UPD: Contest is in around 20 minutes! Please, join!
UPD2: Thanks for participation! We apologize for some technical issues. Upsolving is available: MITIT 2024 Spring Invitational Qualification.
Hi everyone!
2023 Southeastern Europe Regional Contest will take place on December 9. The contest was prepared by Pajaraja, milisav, bicsi, denis2111, antontrygubO_o, and RomaWhite.
Good luck to the official participants!
This contest will be used as Stage 14 of The 2nd Universal Cup (a week after the official contest). Therefore, we ask official participants to not publicly discuss the problems before the Universal Cup Stage.
You will be able to participate in the UCup contest in the following time windows:
Thanks a lot to the Universal Cup committee for providing the platform.
UPD1: Contest livestream
UPD2: Here are Final Standings. Congratulations to the winners!
| Place | Country | Team Name | Contestant 1 | Contestant 2 | Contestant 3 | Problems | Penalty |
|---|---|---|---|---|---|---|---|
| 1 | Ukraine | KhNURE_KIVI | Denisov | Valera_Grinenko | Barichek | 9 | 711 |
| 2 | Ukraine | KNU_0_GB_RAM | KostasKostil | kostia244 | VladProg | 9 | 998 |
| 3 | Ukraine | LNU Stallions | PetroTarnavskyi | mshcherba | Yarema.st | 9 | 1114 |
| 4 | Serbia | Infinity | TadijaSebez | nikolapesic2802 | stefanbalaz2 | 8 | 427 |
| 5 | Ukraine | KNU_Banderolki | danya.smelskiy | Sonechko | Markellonchik | 8 | 834 |
| 6 | Romania | CodeBusters | average_frog_enjoyer | EmanuelDicu | robxln | 8 | 885 |
| 7 | Romania | Concret | vladvlad00 | status_coding | a_dumi | 8 | 959 |
| 8 | Romania | MLP | popovicirobert | loan | toma_ariciu | 7 | 566 |
| 9 | Romania | 3PeasInAPod | BlueDiamond | popabogdannnn | livlivi | 7 | 648 |
| 10 | Romania | UBB_Echipa_Misterelor | georgerapeanu | AlexPop28 | AndreiCotor | 7 | 731 |
UPD3: Editorial
UPD 1 [May 17 2025]: I added my problems from Ukrainian Olympiad in Informatics (among others). They are available here: antontrygubO_o UOI problems
Hi everyone! I wanted to write such a blog for a long time, motivated by similar blogs by adamant and by tibinyte2006; I finally decided to do it after my Universal Cup contest. This is not a super-comprehensive list, I also set some problems for some local contests, but that's most of it.
I want to encourage other setters to write such blogs. For me, it's very interesting to read about the backstories of some problems and also to see all the problems by some author gathered in one place (as most authors give problems to several platforms).
One important point. As you will see from the comments, many of my problems were improved by other people, and I myself improved some problems by other people. I think that it's crucial to have someone to discuss your problems with (apart from the coordinator).
So, here we go.
| # | Date | Problem | Contest | Comment |
|---|---|---|---|---|
| 1 | June 2019 | Vus the Cossack and Strings | Codeforces Round #571 (Div. 2) | |
| 2 | June 2019 | Vus the Cossack and a Graph | Codeforces Round #571 (Div. 2) | My first problem |
| 3 | July 2019 | Keanu Reeves | Codeforces Round #572 (Div. 2) | Split binary string into the smallest number of substrings, in each of which # of 0s is not equal to # of 1s. Initially, we wanted to ask to split into any number of substrings (and the model solution was to split into n characters), but we were told that this is not a real problem |
| 4 | July 2019 | Number Circle | Codeforces Round #572 (Div. 2) | |
| 5 | July 2019 | Candies! | Codeforces Round #572 (Div. 2) | |
| 6 | July 2019 | Add on a Tree | Codeforces Round #572 (Div. 1) | |
| 7 | July 2019 | Add on a Tree: Revolution | Codeforces Round #572 (Div. 1) | We were told to add this problem so that the contest would have at least some implementation |
| 8 | July 2019 | Count Pairs | Codeforces Round #572 (Div. 1) | One of my best problems. Pinnacle of problemsetting... |
| 9 | July 2019 | Make Equal | Codeforces Round #572 (Div. 1) | I came up with the statement, 244mhq with solution |
| 10 | July 2019 | Problem from Red Panda | Codeforces Round #572 (Div. 1) | 244mhq came up with the statement, I with solution |
| 11 | August 2019 | Choose Two Numbers | Codeforces Round #580 (Div. 2) | |
| 12 | August 2019 | Make Product Equal One | Codeforces Round #580 (Div. 2) | |
| 13 | August 2019 | Almost Equal | Codeforces Round #580 (Div. 1) | |
| 14 | August 2019 | Shortest Cycle | Codeforces Round #580 (Div. 1) | |
| 15 | August 2019 | Palindromic Paths | Codeforces Round #580 (Div. 1) | |
| 16 | August 2019 | Almost All | Codeforces Round #580 (Div. 1) | One of my best problems. Unfortunately, a similar idea was used in a problem from IOI 2019 |
| 17 | August 2019 | Expected Value Again | Codeforces Round #580 (Div. 1) | |
| 18 | August 2019 | Beauty of a Permutation | Codeforces Round #580 (Div. 1) | Sadly, I didn't know about permutation tree back then |
| 19 | October 2019 | Find the Array | SEERC 2019 | My best interactive problem |
| 20 | October 2019 | Cycle String? | SEERC 2019 | |
| 21 | October 2019 | Game on a Tree | SEERC 2019 | This is not a good problem, as it indeed is well known for general graphs... Don't do this |
| 22 | October 2019 | Tree Permutations | SEERC 2019 | |
| 23 | October 2019 | Graph and Cycles | SEERC 2019 | |
| 24 | December 2019 | Make Good | Good Bye 2019 | I initially had solution only with adding $$$3$$$ elements. In testing, some testers discovered a solution with $$$2$$$ elements, and after the contest, we realized that it can be solved with only $$$1$$$ element! |
| 25 | December 2019 | Strange Device | Good Bye 2019 | |
| 26 | December 2019 | Divide Points | Good Bye 2019 | One of my best problems |
| 27 | December 2019 | Awesome Substrings | Good Bye 2019 | There is a very nice $$$n\log^2{n}$$$ solution, but we were not able to find it :( |
| 28 | December 2019 | Subset with Zero Sum | Good Bye 2019 | One of my best problems. Initially, I was going to send it to IMO, and there was another problem at this position, but this problem by a recent round by hugopm turned out to be too similar to it :(, so we had to replace it. |
| 29 | December 2019 | Xor on Figures | Good Bye 2019 | Initially, I sent it to IOI 2020, but then decided that it doesn't have meaningful subtasks and that it would be better to use it on CF. I wrote to the PSC and told them that I am retracting the proposal, apologizing. It seems that they missed my email, as in a few months, I received an email from PSC saying: The ISC would like to remind you that this strongly violates the rules of the IOI Call for Tasks, which requires all submitted tasks to be kept strictly confidential until the end of IOI 2020. In the future, if you would like to submit the task elsewhere and not have your task be considered for the IOI, you should email the host directly to let them know of this decision. |
| 30 | February 2020 | So Mean | Codeforces Round #618 (Div. 1) | I just became a coordinator on Codeforces, and wanted to help to conduct the round as soon as possible, so I donated this problem. Now I don't think that it's a good problem... Mostly casework |
| 31 | March 2020 | Kuroni and Impossible Calculation | Ozon Tech Challenge 2020 | |
| 32 | March 2020 | Kuroni and the Score Distribution | Ozon Tech Challenge 2020 | |
| 33 | March 2020 | Kuroni and Antihype | Ozon Tech Challenge 2020 | One of my best problems. Initially, the problem was about the general graph. Unfortunately, minimum arborescence solves the problem, so we had to adjust it this way. |
| 34 | July 2020 | Integer Game | Codeforces Global Round 9 | 244mhq suggested the setup, and I solved it. I will just leave this comment here |
| 35 | July 2020 | Tree Modification | Codeforces Global Round 9 | This is one of the last problems which I created when I still thought that solution->statement is better than statement->solution is a much better way of problemsetting. This problem is a good example of why I switched... making statements not artificial with solution->statement is very hard. |
| 36 | September 2020 | Permutation Forgery | Codeforces Round #668 (Div. 2) | |
| 37 | September 2020 | Watermelon | September Lunchtime 2020 (Div. 2) | |
| 38 | September 2020 | GCD operations | September Lunchtime 2020 (Div. 2) | |
| 39 | September 2020 | Root the Tree | September Lunchtime 2020 (Div. 1) | |
| 40 | September 2020 | Robot Detector | September Lunchtime 2020 (Div. 1) | |
| 41 | September 2020 | Permutation Split | September Lunchtime 2020 (Div. 1) | I was thinking about this problem for quite some time in the background, and then at some point 244mhq brought up the following (old) problem: "Given a graph, check if we can split it into two graphs with same numbers of edges." I realized this problem was a partial case, but the statement was so natural, and the original problem wasn't too well-known from what I've searched, so I decided to still use this problem. Generally, using partial cases of some other problems is a very bad practice... |
| 42 | September 2020 | Few Different Elements | September Lunchtime 2020 (Div. 1) | |
| 43 | September 2020 | Adding on Segments | September Lunchtime 2020 (Div. 1) | My first problem that wasn't solved in the contest |
| 44 | November 2020 | XOR-gun | Technocup 2021 — Elimination Round 2 | |
| 45 | December 2020 | String Operations | Codechef December Challenge 2020 (Div. 1) | |
| 46 | March 2021 | Long Common Subsequence | AtCoder Grand Contest 052 | |
| 47 | March 2021 | Tree Edges XOR | AtCoder Grand Contest 052 | One of my best problems |
| 48 | March 2021 | Nondivisible Prefix Sums | AtCoder Grand Contest 052 | The idea of the setup is by 244mhq in 2020, then I solved it and improved to the counting version |
| 49 | March 2021 | Equal LIS | AtCoder Grand Contest 052 | |
| 50 | March 2021 | 3 Letters | AtCoder Grand Contest 052 | One of my best problems. Thanks to maroonrk for coming up with this nice trick, my initial solution was much more complicated |
| 51 | March 2021 | Tree Vertices XOR | AtCoder Grand Contest 052 | My second problem that wasn't solved in the contest |
| 52 | May 2021 | Reverse Game | SEERC 2020 | |
| 53 | May 2021 | 3-colorings | SEERC 2020 | Initially this was going to be used as AGC52F, but we were afraid of not intended solutions. Sadly, all AC solutions on the mirror were indeed not intended :( In the latter half of $$$2020$$$, I almost stopped coming up with problems; solution->statement didn't work well for me anymore, and I didn't believe I could come up with hard problems in the statement->solution way. This was the first hard problem that I came up with in statement->solution way, and it was the reason why I believed that I can make an AGC set; I messaged maroonrk after I came up with it. |
| 54 | May 2021 | Divisible by 3 | SEERC 2020 | |
| 55 | May 2021 | Fence Job | SEERC 2020 | Initially, I wanted to solve the problem "Choose segment, replace all its elements by their OR, find the number of possible arrays", but my solutions turned out to be wrong. Then bicsi helped to revise the problem into this version |
| 56 | May 2021 | AND = OR | SEERC 2020 | One of my few good data structure problems |
| 57 | May 2021 | Modulo Permutations | SEERC 2020 | |
| 58 | August 2021 | Eulerian? | GP of IMO | |
| 59 | August 2021 | Fancy Formulas | GP of IMO | |
| 60 | August 2021 | Glory Graph | GP of IMO | I was inspired by the fact that for a graph, knowing all degrees, we can find the number of triangles plus antitriangles, so I was looking for some sort of relation for graphs on four nodes. |
| 61 | August 2021 | Hamiltonian | GP of IMO | |
| 62 | August 2021 | Intellectual Implementation | GP of IMO | I was once again inspired by this problem above, and thought that I can try to use this idea for counting something awful. Then, I came up with this statement, and 244mhq helped to solve it |
| 63 | August 2021 | Joke | GP of IMO | |
| 64 | August 2021 | K-onstruction | GP of IMO | Initially 244mhq proposed this problem, asking to construct a set of size at most $$$3\log{K}$$$ for a given $$$K$$$. We were then able to improve it to the bound in the statement. |
| 65 | August 2021 | Little LCS | GP of IMO | Sorry for this problem... but if it fits anywhere, it's a camp training contest |
| 66 | September 2021 | One Pile | September Cook-Off 2021 (Div. 1) | Utkarsh.25dec initially proposed version without counting (just determine who wins). I helped to make it harder, as we needed some hard problems for Cook-Off |
| 67 | October 2021 | Permutating Inversions | October Cook-Off 2021 (Div. 1) | My third problem that wasn't solved in the contest. I wanted to add a pre-last problem to a Cook-Off, as I thought that the contest would be too easy otherwise. Apparently, this problem turned out to be the hardest, with 0 solves, with the next hardest problem having 1 solve... |
| 68 | October 2021 | ABC Identity | AtCoder Grand Contest 055 | Jason Bourne 1 |
| 69 | October 2021 | ABC Supremacy | AtCoder Grand Contest 055 | Jason Bourne 2 |
| 70 | October 2021 | Weird LIS | AtCoder Grand Contest 055 | |
| 71 | October 2021 | ABC Ultimatum | AtCoder Grand Contest 055 | Jason Bourne 3. Initially, the problem was just to check whether a string is good ($$$N \le 2\cdot 10^5$$$), but then AmShZ submitted an unproven greedy in testing, and we were able to improve it to the current version |
| 72 | October 2021 | Set Merging | AtCoder Grand Contest 055 | Certainly my best problem ever, and my fourth problem that wasn't solved in the contest. Read the comment for problem 55 from this list... I decided to solve this problem for OR when $$$a_i = 2^i$$$ initially, and bruteforce + OEIS showed that the answer is the number of sequences with LDS<=3. I was shocked and was stuck on proving this for three days until I finally realized the solution. |
| 73 | October 2021 | Creative Splitting | AtCoder Grand Contest 055 | My initial proposal was: Let's call an array $$$a$$$ of length $$$2n$$$, consisting of integers from $$$1$$$ to $$$n$$$, good, if it is possible to split it into two subsequences of length $$$n$$$, such that in each subsequence $$$i$$$-th element doesn't exceed $$$i$$$ for every $$$i$$$ from $$$1$$$ to $$$n$$$. You are given array $$$a$$$ of length $$$2n$$$, where some numbers are given, and some are $$$−1$$$ (unknown). Find the number of ways to replace $$$−1$$$s with integers from $$$1$$$ to $$$n$$$ so that $$$a$$$ becomes good. With brute force, I knew that the number of "splittable" arrays is $$$\frac{(2n)!}{2^n}$$$ for several months, but I couldn't prove this. Thanks a lot to maroonrk for providing the proof and then for improving my initial proposal to this version. |
| 74 | November 2021 | Many LCS | SEERC 2021 | Initially I needed length of order $$$\sqrt{K}$$$, thanks to Um_nik for improving the problem to the current constraints |
| 75 | November 2021 | Max Pair Matching | SEERC 2021 | |
| 76 | November 2021 | ABC Legacy | SEERC 2021 | Jason Bourne 4 |
| 77 | November 2021 | Counting Phenomenal Arrays | SEERC 2021 | |
| 78 | November 2021 | LIS Counting | GP based on SEERC 2021 | I was really into LIS problems at the time... |
| 79 | December 2021 | Sorting Segments | SnackDown 2021 Online Elimination Round | Yes, this is very similar to Stooge Sort, but I haven't heard about it before setting the problem |
| 80 | December 2021 | Sorter Prodigy | SnackDown 2021 Online Elimination Round | Unfortunately, coincided with CCO '18 P6 :(. This happens |
| 81 | December 2021 | Prefix Suffix LIS Constructing | SnackDown 2021 Online Elimination Round | |
| 82 | January 2022 | Equal Number of Prefix Maximums | SnackDown 2021 Final Round | Unfortunately, this is an easier version of AGC028E :( |
| 83 | January 2022 | Circular Permutation Recovery | January Lunchtime 2022 (Div. 1) | Unfortunately, this turned out to be an easier version of IOI 2020 plants... |
| 84 | January 2022 | Divisible Distances | January Lunchtime 2022 (Div. 1) | |
| 85 | April 2022 | Modular Circular Permutations | April Lunchtime 2022 (Div. 1) | |
| 86 | April 2022 | Odd Split | April Lunchtime 2022 (Div. 1) | |
| 87 | May 2022 | Doubled Distances | May Cook-Off 2022 (Div. 2) | |
| 88 | May 2022 | Triple Inversions | May Cook-Off 2022 (Div. 1) | |
| 89 | May 2022 | Different Subarrays Rearrange | May Cook-Off 2022 (Div. 1) | |
| 90 | May 2022 | Split Powers Of 2 | May Cook-Off 2022 (Div. 1) | |
| 90 | May 2022 | Max Min Circle Difference | May Cook-Off 2022 (Div. 1) | |
| 91 | May 2022 | Plus Xor Increase | May Cook-Off 2022 (Div. 1) | Another rare good algorithmic problem... |
| 92 | May 2022 | Make Grid Comparable | May Cook-Off 2022 (Div. 1) | |
| 93 | May 2022 | Catch Me If You Can | May Cook-Off 2022 (Div. 1) | My fifth problem that wasn't solved in the contest |
| 94 | May 2022 | Everything Everywhere All But One | Codeforces Round #794 (Div. 2) | Watch Everything Everywhere All At Once! |
| 95 | May 2022 | Odd Subarrays | Codeforces Round #794 (Div. 2) | |
| 96 | May 2022 | Circular Local MiniMax | Codeforces Round #794 (Div. 1) | |
| 97 | May 2022 | Bring Balance | Codeforces Round #794 (Div. 1) | |
| 98 | May 2022 | Permutation Weight (Easy Version) | Codeforces Round #794 (Div. 1) | |
| 99 | May 2022 | Permutation Weight (Hard Version) | Codeforces Round #794 (Div. 1) | |
| 100 | May 2022 | The Ultimate LIS Problem | Codeforces Round #794 (Div. 1) | One of my best problems |
| 101 | June 2022 | Split AND Sum | June Cook-Off 2022 (Div. 1) | |
| 102 | June 2022 | Prefix Suffix Distinct | June Cook-Off 2022 (Div. 1) | |
| 103 | June 2022 | Max Minus Min | June Cook-Off 2022 (Div. 1) | This problem was initially proposed by jainmilind for $$$A, B, C \le 10^6$$$, I was able to improve it to the current constraints |
| 104 | June 2022 | XOR, The Detective | June Lunchtime 2022 (Div. 1) | |
| 105 | June 2022 | SPLIT With XOR Not X | June Lunchtime 2022 (Div. 1) | Filler problem, made just for all XOR contest |
| 106 | September 2022 | Longest Unfriendly Subsequence | EJOI 2022 | |
| 107 | September 2022 | Permutations LCS | EJOI 2022 | Dear EJOI 2022 participants. I am deeply sorry for your destroyed mental health |
| 108 | September 2022 | Anti-Increasing Addicts | Codeforces Global Round 22 | |
| 109 | November 2022 | Anti-median (Easy Version) | Pinely Round 1 (Div. 1 + Div. 2) | |
| 110 | December 2022 | My Last ABC Problem | AtCoder Grand Contest 059 | From now on, only problems about 123 |
| 111 | December 2022 | Arrange Your Balls | AtCoder Grand Contest 059 | |
| 112 | December 2022 | Guessing Permutation for as Long as Possible | AtCoder Grand Contest 059 | When I first came up with a statement and solved it, I thought that the problem is standard and garbage. It turned out I was extremely wrong... |
| 113 | December 2022 | Distinct Elements on Subsegments | AtCoder Grand Contest 059 | I came up with the statement in May of $$$2022$$$ and couldn't solve for three months. |
| 114 | December 2022 | Grid 3-coloring | AtCoder Grand Contest 059 | Initially, I proposed a version with construction for $$$n \lt =100$$$, and my proof was extremely hard (and greedy). A week before the contest maroonrk realized that we can use the same idea as in AGC052E, and the problem became much nicer. Unfortunately, this idea turned out to be present in some papers... |
| 115 | December 2022 | LIDS | AtCoder Grand Contest 059 | My sixth problem that wasn't solved in the contest, and, probably, the hardest problem that I ever made. In March 2022, I noticed that the number of permutations of length $$$n$$$ with $$$LIS = x, LDS = n+1-x$$$ is $$$C(n-1, x-1)^2$$$. (Yes, this is easy with the Robinson–Schensted correspondence, but I didn't know it). I was able to prove this only in August, and after finding a nice bijection in the process, I decided that I can try to write a third AGC. |
| 116 | December 2022 | Divisible by 4 Spanning Tree | SEERC 2022 | |
| 117 | December 2022 | Exercise | SEERC 2022 | |
| 118 | December 2022 | Inadequate Operation | SEERC 2022 | |
| 119 | February 2023 | Adjacent Product Sum | Universal Cup 1 Stage 4: Ukraine | |
| 120 | February 2023 | Binary Arrays and Sliding Sums | Universal Cup 1 Stage 4: Ukraine | |
| 121 | February 2023 | Count Hamiltonian Cycles | Universal Cup 1 Stage 4: Ukraine | My initial solution was in $$$O(n^2)$$$, thanks to Um_nik for improving it to $$$O(n)$$$ |
| 122 | February 2023 | Distance Parities | Universal Cup 1 Stage 4: Ukraine | |
| 123 | February 2023 | Excellent XOR Problem | Universal Cup 1 Stage 4: Ukraine | |
| 124 | February 2023 | F*** 3-Colorable Graphs | Universal Cup 1 Stage 4: Ukraine | Like... who tf likes 3-colorable graphs? |
| 125 | February 2023 | Graph Problem With Small $n$ | Universal Cup 1 Stage 4: Ukraine | This problem was born when me and 244mhq were discussing how to implement checker to Hamiltonian from our Ptz contest... We were surprised that we haven't seen it before, and it seems that almost no one has seen it. Apparently, Golovanov399 showed that this is standard exercise :( |
| 126 | February 2023 | Help Me to Get This Published | Universal Cup 1 Stage 4: Ukraine | Please, help me to get this published |
| 127 | February 2023 | Increasing Grid | Universal Cup 1 Stage 4: Ukraine | One of my most standard problems, but I decided that having such problem in an ICPC contest is good |
| 128 | February 2023 | Jewel of Data Structure Problems | Universal Cup 1 Stage 4: Ukraine | |
| 129 | February 2023 | King of Swapping | Universal Cup 1 Stage 4: Ukraine | |
| 130 | February 2023 | Least Annoying Constructive Problem | Universal Cup 1 Stage 4: Ukraine | My best constructive problem |
| 131 | February 2023 | Most Annoying Constructive Problem | Universal Cup 1 Stage 4: Ukraine | My seventh problem that wasn't solved in a contest, and the first one that wasn't solved in ICPC format |
| 132 | February 2023 | No Zero-Sum Subsegment | Universal Cup 1 Stage 4: Ukraine | |
| 133 | March 2023 | An Array and Several More Arrays | UOI 2023 Day 1 | |
| 134 | March 2023 | An Array and Range Additions | UOI 2023 Day 1 | |
| 135 | March 2023 | An Array and Medians of Subarrays | UOI 2023 Day 2 | |
| 136 | March 2023 | An Array of Characters and Almost Palindromes | UOI 2023 Day 2 | |
| 137 | December 2023 | Jackpot | SEERC 2023 | |
| 138 | December 2023 | $K$ Subsequences | SEERC 2023 | |
| 139 | December 2023 | LIS on Grid | SEERC 2023 | |
| 140 | December 2023 | Max Minus Min | SEERC 2023 | |
| 141 | March 2024 | Charming Meals | European Championship 2024 | Just a few days before the contest, we realized that the problemset was too hard, and had to come up with something almost everyone would solve. |
| 142 | March 2024 | Make Triangle | European Championship 2024 | |
| 143 | March 2024 | Queries for Subarray Beauty | UOI 2024 Day 1 | |
| 144 | March 2024 | Colorful Table | UOI 2024 Day 2 | |
| 145 | March 2024 | Heroes and Monsters | UOI 2024 Day 2 | |
| 146 | May 2024 | Distance Mod 5 | MIT Informatics Tournament 2024 Finals | |
| 147 | May 2024 | Avoid XOR Zero | MIT Informatics Tournament 2024 Finals | We had to come up with a hard problem for finals, so I went to the usual place for inspiration: AtCoder. This problem is, obviously, heavily inspired by AGC065C |
| 148 | June 2024 | Aibohphobia | Universal Cup 3 Stage 4: Ukraine | |
| 149 | June 2024 | Breaking Bad | Universal Cup 3 Stage 4: Ukraine | |
| 150 | June 2024 | Chemistry Class | Universal Cup 3 Stage 4: Ukraine | |
| 151 | June 2024 | Daily Disinfection | Universal Cup 3 Stage 4: Ukraine | |
| 152 | June 2024 | Equalizer Ehrmantraut | Universal Cup 3 Stage 4: Ukraine | |
| 153 | June 2024 | Formal Fring | Universal Cup 3 Stage 4: Ukraine | |
| 154 | June 2024 | Goodman | Universal Cup 3 Stage 4: Ukraine | |
| 155 | June 2024 | Highway Hoax | Universal Cup 3 Stage 4: Ukraine | |
| 156 | June 2024 | Increasing Income | Universal Cup 3 Stage 4: Ukraine | |
| 157 | June 2024 | Jesse's Job | Universal Cup 3 Stage 4: Ukraine | |
| 158 | June 2024 | Knocker | Universal Cup 3 Stage 4: Ukraine | Still hard to believe that it's solvable... |
| 159 | June 2024 | Lalo's Lawyer Lost | Universal Cup 3 Stage 4: Ukraine | |
| 160 | November 2024 | NonZero PrefSuf Sums | The 2024 ICPC Southeastern Europe Regional Contest (SEERC 2024) | |
| 161 | November 2024 | Shrooks | The 2024 ICPC Southeastern Europe Regional Contest (SEERC 2024) | |
| 162 | November 2024 | Shreckless | The 2024 ICPC Southeastern Europe Regional Contest (SEERC 2024) | |
| 163 | January 2025 | Not-So-Long Increasing Subsequence | MITIT Winter 2025 Advanced Round 1 | |
| 164 | January 2025 | Colored Blocks | MITIT Winter 2025 Advanced Round 2 | |
| 165 | March 2025 | Boys and Girls | UOI 2025 Day 1 | |
| 166 | March 2025 | Partitioning into Three | UOI 2025 Day 1 | |
| 167 | March 2025 | Convex Array | UOI 2025 Day 1 | |
| 168 | March 2025 | Simple Subsequence | UOI 2025 Day 1 | |
| 169 | March 2025 | Manhattan Pairing | UOI 2025 Day 2 | |
| 170 | March 2025 | Reversal ABC | UOI 2025 Day 2 | |
| 171 | April 2025 | Beaverland | MITIT Spring 2025 Qualification Round 1 | |
| 172 | April 2025 | Anti-Sorting Game | MITIT Spring 2025 Qualification Round 1 | |
| 173 | April 2025 | Indivisible Inversions | MITIT Spring 2025 Qualification Round 2 | |
| 174 | May 2025 | Beautiful Bracelets | MITIT Spring 2025 Finals Round | |
| 175 | May 2025 | Escape Room | MITIT Spring 2025 Finals Round |
Hello everyone! The 4th Stage of the 1st Universal Cup: Ukraine, will be held on Feb 18th, 2023.
The contest is based on 1/8 and 1/4 Ukrainian stages of SEERC 2023, plus some extra problems. Please, don't participate, if you have seen these problems. This contest also serves as Day 1 in Osijek Competitive Programming Camp 2023 on February 18, 2023.
Author of all problems: antontrygubO_o. I hope you like the problems.
You can participate in the contest in the following three time windows:
Please note that you can see two scoreboards in DOMjudge. The 'Local Scoreboard' shows the standings ONLY IN THE CURRENT TIME WINDOW. And the 'Combined Scoreboard' shows all participants, including the onsite participants, and the cup participants in the previous time windows.
Contest link: https://domjudge.qoj.ac/
Universal Cup Scoreboard: https://qoj.ac/ucup/scoreboard
About Universal Cup:
Universal Cup is a non-profit organization dedicated to providing trainings for competitive programming teams. Up to now, there are more than 200 teams from all over the world registering for Universal Cup.
A more detailed introduction: https://codeforces.me/blog/entry/111672
Register a new team: https://ucup.ac/register
UPD1: Thanks for your participation! Here is Editorial.
I also uploaded contest to gym: Anton Trygub Contest 1 (The 1st Universal Cup, Stage 4: Ukraine).
I hope to add ghost participants by tomorrow.
We invite you to participate in CodeChef’s February Cookoff 2023, this Wednesday, 08th February, rated for all.
Time: 8 PM — 10:30 PM IST
From admins. We apologize for the absence of Div. 1 contests. In the first half of 2022, we were trying hard to hold them on a regular basis. This was already challenging, as the number of high-quality proposals, especially hard ones, was very small; we had to use our own problems in almost every contest. This couldn't continue for long.
We would like Codechef Div. 1 contests to come back, but for this, we need your help. The Div.1 problems of the next few contests will be based on The Leo Camp 2022, a Ukrainian programming camp that took place in the summer of 2022, and, possibly, our own problems. But we need your problems to continue making these contests. So, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, please, share them here.
If you participated in The Leo Camp 2022, please, don't participate in this contest.
Joining us on the problem setting panel are:
Setters: Kanhaiya notsoloud1 Mohan, anky_301, neerav_1, Danish danishiitp_24, M.Sohel, VladProg VladProg, KostasKostil KostasKostil, kostia244 kostia244, BigBag BigBag, Barichek Barichek, Mustang98 Mustang98, shanin shanin, RomaWhite RomaWhite, witua witua, Andrew_Makar Andrew_Makar
Testers: Nishank IceKnight1093 Suresh , Jatin rivalq Garg
Written editorials will be available for all on discuss.codechef.com. Pro users can find the editorials directly on the problem pages after the contest.
The video editorials of the problems will be available for all users for 1 day as soon as the contest ends, after which they will be available only to Pro users.
Hope to see you participating. Good Luck!
Hi everyone!
2022 Southeastern Europe Regional Contest will take place tomorrow, on December 10. The contest was prepared by bicsi, antontrygubO_o, theodor.moroianu, lungualex00, eudanip.
Good luck to the official participants!
There will be a mirror of this contest this Sunday, December 11, 08:00 UTC. It will be held by the link https://seerc2022.eolymp.io/.
We hope that you will enjoy the contest! See you on the scoreboard.
UPD1: Congratulations to the winners of SEERC!
This year, the contest was held on two sites, Ukrainian and Romanian.
Standings and Top 5 of Ukrainian site:
| Place | Team Name | Contestant 1 | Contestant 2 | Contestant 3 | Problems | Penalty |
|---|---|---|---|---|---|---|
| 1 | [Ukraine] LNU Stallions | Yarema.st | mshcherba | PetroTarnavskyi | 9 | 1091 |
| 2 | [Ukraine] UzhNU_OLDS | Fekete | YaroslavBulyna | illyakr | 7 | 1129 |
| 3 | [Ukraine] LNU NextGen | FEREND | Ebiarat | RHplu51 | 6 | 916 |
| 4 | [Ukraine] KhNURE_(-_-(-_-)-_-) | log2win | Phys-mat_KCh | avoronoi | 6 | 1044 |
| 5 | [Ukraine] UzhNU_3yagoda | VasyaMer | tedi_2.0 | Happy.CoDer | 5 | 445 |
Standings and Top 5 of Romanian site:
| Place | Team Name | Contestant 1 | Contestant 2 | Contestant 3 | Problems | Penalty |
|---|---|---|---|---|---|---|
| 1 | [Serbia] Infinity | nikolapesic2802 | TadijaSebez | stefanbalaz2 | 11 | 1272 |
| 2 | [Cyprus] bird-cherry | buyolitsez | GrandFruit | step_by_step | 10 | 1516 |
| 3 | [Serbia] GII Klub | MladenP | milisav | Pajaraja | 10 | 1603 |
| 4 | [Romania] Echipa Sarata | alexandra_udristoiu | popabogdannnn | Stelutzu | 9 | 1268 |
| 5 | [Serbia] UoB R-Shuf | Djordjevic | VladaMG98 | JovanB | 8 | 1018 |
Once again, we invite you to the mirror tomorrow.
UPD2: Editorial
UPD3: The contest was uploaded to the gym: 2022 ICPC Southeastern Europe Regional Contest. I will add results of official participants soon.
I am glad to invite you to AtCoder Grand Contest 059. This contest counts for GP30 scores.
The point values will be added soon.
I would like to thank:
I really hope you will like the problems.
We are looking forward to your participation!
UPD1: Point values are $$$500$$$ — $$$700$$$ — $$$1100$$$ — $$$1100$$$ — $$$1400$$$ — $$$1900$$$
UPD2: Thanks for your participation!
The winners are:
1. ksun48
2. Petr
3. tatyam
4. hitonanode
5. tourist
We invite you to participate in CodeChef’s September Lunchtime, this Friday , 23rd September, rated for all. It is based on EJOI 2022, the second day of which takes place earlier on the same day. All EJOI participants were asked to not discuss the problems before the end of this contest, and to not participate in this contest. If you somehow got to know some of the problems, please, don't participate.
Time: 8:00 PM — 11:30 PM IST
Please note that the contest duration is unusual — 3.5 Hours.
Joining me on the problem setting panel are:
Setters of EJOI: Ray gotexans Bai, Anton antontrygubO_o Trygub, Matvey BigBag Aslandukov, Ihor Barichek Barenblat, Roman RomaWhite Bilyi, Jeroen Op de jeroenodb Beek
Setters of extra problems for this contest: Utkarsh Utkarsh.25dec Gupta, Jeevan Jyot JeevanJyot Singh, Ashish Ashishgup Gupta
Testers: I want to thank countless testers of EJOI: kostia244, welleyth, KostasKostil, VladProg, timreizin, Um_nik, 244mhq, errorgorn
Contest Admins: Anton antontrygubO_o Trygub, Yahor 244mhq Dubovik, Jeevan Jyot JeevanJyot Singh
Editorialist: Nishank IceKnight1093 Suresh
I want to separately thank arsijo for his colossal work put into the organization of EJOI.
The video editorials of the problems will be available for all users for 1 day as soon as the contest ends, after which they will be available only to Pro users.
Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Hope to see you participating. Good Luck!
We invite you to participate in CodeChef’s June Lunchtime, this Sunday, 19th June, Rated for All.
Joining me on the problem setting panel are:
Setters: Anton antontrygubO_o Trygub, Yahor 244mhq Dubovik,Utkarsh Utkarsh.25dec Gupta,Alex Um_nik Danilyuk,Jeevan Jyot JeevanJyot Singh
Tester: Harris Harris gamegame Leung
Statement Verifier: Kanhaiya notsoloud1 Mohan
Contest Admin: Anton antontrygubO_o Trygub, Yahor 244mhq Dubovik,Utkarsh Utkarsh.25dec Gupta
Head Admin: Alex Um_nik Danilyuk
Editorialist: Đặng Đoàn Kuroni Đức Trung
The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.
Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Hope to see you participating. Good Luck!
We invite you to participate in CodeChef’s June Cook-Off, this Sunday, 5th June, Rated for All.
Time: 8:00 PM — 10:30 PM IST
Joining me on the problem setting panel are:
Tester: Harris gamegame Leung
Statement Verifier: Nishank IceKnight1093 Suresh
Contest Admins:Anton antontrygubO_o Trygub, Yahor 244mhq Dubovik
Head Admin: Alex Um_nik Danilyuk
Editorialist: Đặng Đoàn Kuroni Đức Trung
Also, announcing Scholarship for CodeChef Certification in Data Structure & Algorithms — More than 100 Indian participants in Divisions 1, 2, and 3 will win scholarships for the CodeChef Certification exam (discounted prices). Scholarship criteria can be found on the respective contest pages.
The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.
Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Hope to see you participating. Good Luck!
I hope you enjoyed the round.
While problem D1B was good for balance in Div1, it was too hard for balance in Div2. I apologize for this.
Problem D1B = D2D is by dario2994. Other problems are mine.
Tutorial of Codeforces Round 794 (Div. 1)
Tutorial of Codeforces Round 794 (Div. 2)
We will hold Codeforces Round 794 (Div. 1) and Codeforces Round 794 (Div. 2).
The point values will be:
Div2: 500 — 1000 — 1500 — 2000 — 2500 — 2500
Div1: 500 — 1000 — 1500 — (1500 + 1500) — 3500
We are looking forward to your participation!
UPD 1: Thanks to NEAR for supporting this round, details can be found in this post.
UPD 2: Editorial
UPD 3: Congratulations to winners!
Div1:
1. heuristica
2. jiangly
3. ecnerwala
4. gamegame
5. maroonrk
Div2:
1. lmqzzz
2. Teating_
3. lunchbox
4. Nida1097
5. demacia
Announcement of Codeforces Round 794 (Div. 1)
Announcement of Codeforces Round 794 (Div. 2)
We invite you to participate in CodeChef’s May Lunchtime, this Sunday, 15th May, rated for all.
Time: 8:00 PM — 11:00 PM IST
Joining me on the problem setting panel are:
Setters: Mradul bhatnagar.mradul Bhatnagar, Manuj DarkSparkle Nanthan, Nishank IceKnight1093 Suresh, Valerio TheScrasse Stancanelli, Dan DannyBoy, Hazem zoooma13 Tarek, Hrishikesh hrishik85 Kelker, Yahor 244mhq Dubovik, Boris PuRpLe_FoReVeR Serenkov
Tester: Harris gamegame Leung
Head Admin: Alex Um_nik Danilyuk
Statement Verifier: Nishank IceKnight1093 Suresh
Contest Admins: Yahor 244mhq Dubovik, Anton antontrygubO_o Trygub
Editorialist: Đặng Đoàn Kuroni Đức Trung
Also, announcing Scholarship for CodeChef Certification in Data Structure & Algorithms — More than 100 Indian participants in Divisions 1, 2, and 3 will win scholarships for the CodeChef Certification exam (discounted prices). Scholarship criteria can be found on the respective contest pages.
The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.
Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Hope to see you participating. Good Luck!
We invite you to participate in CodeChef’s May Cook-Off, this Sunday, 1st May, Rated for All.
Time: 8:00 PM — 11:00 PM IST
Note that from this month, Cook-Off and Lunchtimes will be held on Sundays instead of on Saturdays.
Joining me on the problem setting panel are:
Setters: Yashodhan ay21 Agnihotri, Utkarsh Utkarsh.25dec Gupta, Anton antontrygubO_o Trygub, Nishank IceKnight1093 Suresh, Daanish 7dan Mahajan
Tester: Harris gamegame Leung
Head Admin: Alex Um_nik Danilyuk
Statement Verifier: Nishank IceKnight1093 Suresh
Contest Admin: Anton antontrygubO_o Trygub
Editorialist: Anton antontrygubO_o Trygub
A couple of extra words about the contest:
All Div-1 problems have been set by me.
The contest is harder than usually, so the duration is changed to 3 hours instead of 2.5 hours
I hope everyone will enjoy the contest!
Also, announcing Scholarship for CodeChef Certification in Data Structure & Algorithms — More than 100 Indian participants in Divisions 1, 2, and 3 will win scholarships for the CodeChef Certification exam (discounted prices). Scholarship criteria can be found on the respective contest pages.
The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.
Also, if you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Hope to see you participating.
Good Luck!
I know that a lot of people here care about the war in Ukraine. If you are looking for ways to help, please, visit this link: http://linktr.ee/help_ukraine_global. Any support matters, any help matters.
Please, help to stop the bloody dictator of our neighbor.
UPD1: Another very good site
UPD2: With this website you can help to show Russians what's really going on in Ukraine. Props to this post.
UPD3: If your CF profile had country set to Ukraine at the moment of this post, and you haven't created Crowdforces account yet, you can do it by this link: https://nearcrowd.com/crowdforces, and receive 12 Near (which is around 100$ now).
You can find detailed instructions here. This document is available only in Ukrainian for now. Please, use this money for the maximum benefit.
We invite you to participate in CodeChef’s January Lunchtime, this Saturday; 29th January from 8:00 PM — 11:00PM IST.
The contest will be 3 hours long. There will be 5 problems in Div 1/2 and 6 problems in Div 3. It will be rated for all three Divisions.
Joining us on the problem setting panel are:
Contest Admins: Yahor 244mhq Dubovik and Anton antontrygubO_o Trygub
Head Admin: Alex Um_nik Danilyuk
Tester: Takuki tabr Kurokawa
Setters: Utkarsh Utkarsh.25dec Gupta, Daanish 7dan Mahajan, Soumyadeep soumyadeep_pal_21 Pal, Lokesh lucky_21 Singh, Anton antontrygubO_o Trygub, Daniel dannyboy20031204 Chiang, Manuj DarkSparkle Nanthan, Yahor 244mhq Dubovik
Editorialist: Daanish 7dan Mahajan
The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.
Problem Submission: If you have original problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Prizes:
Good luck and have fun!
P.S. I think that problems are interesting, I encourage everyone to try them!
It’s finally time for one of the biggest events in the competitive programming world. The SnackDown ‘21 Grand Finale is here.
The entire Grand Finale event is scheduled to be completed in two days — January 8 (Saturday), and January 9 (Sunday).
All the information has been shared over email, but summarising — The Grand Finale will be spread over two days and will be a closed event accessible only to the finalists, and a few invited guests. The SnackDown 2021 Final contest will be held on Jan 9th between 6:30 — 10:30 PM (IST).
For the last time for this SnackDown, meet the panelists!
For those who would like to have a taste of the SnackDown Final problems, we also have the SnackDown Final Parallel Unrated Contest scheduled for January 9, 2022, 6:30 PM — 10:30 PM (IST). The problems will be the same as the Finale. Since the main Finals will be a restricted session, the rank list can be viewed here. Note that the rank list will be frozen for the last hour, and will be resolved in the post-contest ceremony on YouTube.
The SnackDown ‘21 Finale closing ceremony will start on Jan 9th at 10.30 PM IST. It will be hosted by Kamil Debowski and Ashish Gupta, who will be analyzing the contest problems and the strategies and performances of the participants. This is also where you can witness the moment of truth, the SnackDown ‘21 Grand Finale winner announcement! Everyone is cordially invited to the event, and we request you to set your reminders here.
As the last big contest of 2021 is over, I think it's time.
It seems that there were just more and more ad-hocs/"deeply analyze some complicated process" everywhere... But maybe you still liked something.
So, what were your favorite problems in 2021?
We are very glad to invite you to participate in SnackDown Elimination round! It will be rated for all participants.
60 participants will qualify for the finals from the Elimination round. They include:
Those, who haven't advanced, are invited to participate in the Parallel rounds, which will be held for all divisions. All three rounds are rated too.
Please note that the duration was initially written as 5 hours by mistake, it will actually be 3 hours. The Finals duration will also be less than 5 hours.
Joining us on the problem setting panel are:
Users who have qualified to participate in the SnackDown Elimination should not participate in the Parallel rounds.
The Div-1 Parallel round and the Elimination ranklists will be merged to determine the winners of the cash/Amazon voucher prizes.
If you have some original and engaging problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Hope to see you participating. Good luck and have fun!
Hi everyone!
2021 Southeastern Europe Regional Contest took place on November 21. Here you can view the full standings.
Congratulations to the winners of the contest!
| Place | Team Name | Contestant 1 | Contestant 2 | Contestant 3 | Problems | Penalty |
|---|---|---|---|---|---|---|
| 1 | [Taras Shevchenko National University of Kyiv] KNU_0_GB_RAM | KostasKostil | VladProg | kostia244 | 13 | 1788 |
| 2 | [Kharkiv National University of Radio Electronics] KhNURE_Energy is not over | BigBag | Barichek | Mustang98 | 12 | 1274 |
| 3 | [Lviv National University] LNU Bulldogs | mshcherba | Vasyl_Protsiv | PetroTarnavskyi | 11 | 1429 |
| 4 | [Faculty of Computer Science, Belgrade] GII Klub | milisav | Pajaraja | MladenP | 11 | 1433 |
| 5 | [V.N. Karazin Kharkiv National University] KhNU_OtVinta | kilt_01 | Stroustrup | 13022001 | 11 | 1444 |
| 6 | [University of Bucharest] Unibuc Scrambled Eggs | Rpd-Strike | theodor.moroianu | livlivi | 11 | 1527 |
| 7 | [Taras Shevchenko National University of Kyiv] KNU_Duplee | Sonechko | danya.smelskiy | stanislav.bezkorovainyi | 11 | 1608 |
| 8 | [University of Bucharest] EchipaDulce | Usu | Stelutzu | alexandra_udristoiu | 10 | 1350 |
| 9 | [Kharkiv National University of Radio Electronics] KhNURE_Lacrimosa | kupriyanov | dendi239 | viskonsin | 9 | 1068 |
| 10 | [Babes-Bolyai University] UBB_Zalau00 | Bodo | georgerapeanu | AlexPop28 | 9 | 1183 |
There will be a Grand Prix of Southeastern Europe based on these problems this Sunday, November 28, 08:00 UTC. Here is the link to the OpenCup.
This year, the sets of SEERC and OpenCup are a bit different: OpenCup won't include a few easier problems from SEERC and will additionally include several harder problems. In addition, problems are shuffled, so don't follow the standings of the official contest too much.
The authors of the OpenCup set are eudanip, Um_nik, bicsi, RomaWhite, Andrei1998, and me, antontrygubO_o. After the contest, the editorials to both versions of the contest will be published, and both versions of the contest will be uploaded to the gym.
We hope that you will enjoy the contest!
UPD:
Editorials:
Both contests are uploaded to Gym:
Announcement of 2021 ICPC Southeastern Europe Regional Contest
Announcement of XXII Open Cup, Grand Prix of Southeastern Europe
I am glad to invite you to AtCoder Grand Contest 055. This contest counts for GP30 scores.
The point values will be 400 — 700 — 900 — 1200 — 1500 — 1800
I would like to thank:
Problem statements will be short again, and I really hope that you will like the problems. However, I have to warn you that contest will be closer to ABC than to AGC...
We are looking forward to your participation!
UPD1: Thanks for your participation!
The winners are:
1. ksun48
2. tourist
3. OddImage
4. hos.lyric
5. EvenImage
Special congratulations to tranquility , the only person to solve F.
Sadly, nobody got E in the contest time, though a few people were close. I encourage you to try it, or to read editorial, I think that it's the best problem I ever invented.
I hope you enjoyed the contest!
We invite you to participate in CodeChef’s October Cookoff, this Sunday; 24th October from 9:30 PM — 12:00AM IST.
The contest will be 2.5 hours long. There will be 7 problems in Div 1/2 and 8 problems in Div 3. It will be rated for all three Divisions.
Joining us on the problem setting panel are:
Contest Admins: Ashish Ashishgup Gupta and Anton antontrygubO_o Trygub
Head Admin: Alex Um_nik Danilyuk
Tester: Danny Tlatoani Mittal
Setters: Jeevan JeevanJyot Jyot Singh, Anshu _runtimeTerror_ Garg, Rahul sapora Kumar, Prasant prasant21 Kumar, Shiva Agnimandur Oswal, Sandeep dazlersan1 V, Anton antontrygubO_o Trygub, Utkarsh Utkarsh.25dec Gupta, Lavish lavish315 Gupta, Ashish 7KIRA1999 Kumar
Statement Verifier: Trung Kuroni Dang
Editorialist: Nishank IceKnight1093 Suresh
Video Editorialists and Translators will be added a bit later
Problem Submission: If you have original problem ideas, and you’re interested in them being used in CodeChef's contests, you can share them here.
Prizes:
Global Rank List:
Indian Rank List:
The video editorials of the problems will be available on our YouTube channel as soon as the contest ends. Subscribe to get notifications about our new editorials.
Good luck and have fun!
P.S. Seriously, try it, I think problems are interesting :P
UPD1: Sorry for confusion, the duration is 2.5 hours.
This summer, me and 244mhq held a contest in Petrozavodsk Programming Camp. $$$1$$$ problem was provided by gepardo, and we are very thankful for that, and other problems were created by us, 244mhq and antontrygubO_o. This contest will be held as an OpenCup contest on September 19, 11:00 UTC+3.
I and 244mhq are friends for long time, since our years of participation at IMO, and it's 244mhq who introduced me to competitive programming. Therefore, we decided to call this contest GP of IMO.
Link (OpenCup login needed to participate)
I will publish the editorial here soon after the contest ends.
Good luck and have fun!
UPD1: Shame on me, I forgot to thank testers of this contest: gamegame, Geothermal, nitrousoxide.
UPD2: Editorial
