Code Festival 2016: интервью и фотографии участников [Code Festival 2016](http://mirror.codeforces.com/blog/entry/48616) прошел в Токио 25-30 ноября. Борис Минаев поделился своими впечатлениями о поездке, фотографиями — Максим Ахмедов и Николай Калинин. — _Итак,_ [AtCoder](https://atcoder.jp/) _и компания_ [Indeed](http://ru.indeed.com/about) _анонсировали фестиваль. Сколько было отборов и по какой схеме они проходили?_ — Было 3 контеста, в которых можно поучаствовать. В первом контесте топ-10 проходит, во втором топ-5 и в третьем топ-5. И вот суммарно 20 человек проходит иностранцев. — _А у японцев какие отборы были?_ — Видимо те же самые, только там 200 человек прошло. — _То есть мероприятие больше на японцев ориентировано?_ — В прошлые годы мероприятие было только для японцев, а тут они решили позвать еще иностранцев. — _Отборочные контесты сколько шли?_ — Был довольно короткий контест, час двадцать или два часа. Чтобы пройти, нужно было решить все зада...

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Video Editorials for Olympiad Problems Hi everyone, Quarantine, though necessary, is honestly a tad boring, especially the months between school and college. So........ I recently started a Youtube channel (coz why not), and intend to post some solutions to OI Problems I have solved in the past year. I will discuss solutions from POI/BOI/CEOI/JOI etc, and expect the problems to be from 1900-2600 difficulty level (?!). Obviously, these will be just the problems I have managed to solve, with/without help, so they won't be super tough. Also, some of these problems might not have proper editorials or at least English translated ones, so hopefully, it will be useful. **Polish Olympiad in Informatics:** 2014: [POI — 2014 — Round2 — Day2 — LittleBird](https://www.youtube.com/watch?v=unTiJSIxvCE&t=9s) [POI — 2014 — Round2 — Day2 — Rally](https://www.youtube.com/watch?v=FKq36nNqreA&t=36s) 2018: [POI — 2018 — Round2 — Day1 — BikePa...

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VNOI Cup 2022 Round 2 [Mirror invitation] Hello again Codeforces! <!-- Short sentence for invitation --> We are glad to invite you to take part in mirror round of [the second round of VNOI Cup](https://oj.vnoi.info/contest/vnoicup22_r2_mirror), which will take place [at 13:00 UTC, on this Saturday, 25th June](https://www.timeanddate.com/worldclock/fixedtime.html?msg=%5BMirror%5D%20VNOI%20Cup%202022%20-%20Round%202&iso=2022-06-25T13:00:00), and it is hosted on our builtin platform &mdash; [VNOJ](https://oj.vnoi.info/)! <center> <img src="/predownloaded/0c/04/0c04e729c4ba111d2f61cd6aaabd649b844d1887.png" alt="round2-poster" /> </center> <!-- Ask qualified participants to take part in the official round --> **If you are Vietnamese and _qualified_ according to these rules mentioned on [this post](https://cup.vnoi.info/rule/)**, please consider taking part in [the official round](https://oj.vnoi.info/contest/vnoicup22_r2)! <!-- Introduce VNOI --> VNOI Cup is a Competitive Programming competition held by VNOI (Viet...

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CODE FESTIVAL 2017 Onsite Event The onsite event of CODE FESTIVAL 2017 will start soon. There will be four contests during the event: - [Final Round](https://cf17-final-open.contest.atcoder.jp/). This is the main contest. - [Exhibition Match](https://cf17-exhibition-open.contest.atcoder.jp/). - Three rounds of Elimination Tournaments [1](https://cf17-tournament-round1-open.contest.atcoder.jp/) [2](https://cf17-tournament-round2-open.contest.atcoder.jp/) [3](https://cf17-tournament-round3-open.contest.atcoder.jp/) - [Team Relay](https://cf17-relay-open.contest.atcoder.jp/). All contests will have parallel rounds. Only Final will be rated (and corresponding parallel round will be rated too). Check the schedule of the contests at https://atcoder.jp/. UPD: Now the final standings is available at https://beta.atcoder.jp/contests/cf17-final/standings. Congratulations to winners: 1. [user:tourist,2017-11-25] 2. [user:ksun48,2017-11-25] 3. [user:Um_nik,2017-11-25] 4. [user:Marcin_smu,2017-11-25]...

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Busy but Master #2 Alternative name: "Road to Master when you don't have time". Episode 1: [link](https://mirror.codeforces.com/blog/entry/133458) Episode 2: September 2024 > See you in a month when I'm purple. Just unlucky?:) Two months of grinding Codeforces and I'm still not purple. It might seem like a failure, but if I look closely, I can see significant improvement compared to my performance in August. ### Practice results I feel like in the second half of the month, I've lost my ability to think properly, feel so dumb. Maybe it's just an illusion because I’m solving 2200-2400 rated problems instead of 1800, but still, it feels strange. I motivate myself by reminding that this must be a transitional stage, after which I'll see a big boost. University has started, and while it hasn’t taken up much of my time yet, I already spend ~full,2024-10-04 saturday for it. Plus, I spend a few hours a week chilling on social media, so compared to August, I probably have only about 70% of that ti...

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2022 Joint exam of 5 schools (GZEZ Round2) Editorial [A. Refreshed](https://mirror.codeforces.com/gym/104538/problem/A) ------------------ If we don't take the shortest path from $s$ to $t$ but instead detour to some vertices to gain health, we must pass through an edge with both endpoints having a sum of weights greater than 0. If we reach either vertex of such an edge, we can gain infinite health. We mark such vertices as infinite health vertices. So, either we take the shortest path from $s$ to $t$, or we take the shortest path from $s$ to an infinite health vertex, gain infinite health, and then walk to $t$. The second case can be maintained through up and down DP, which keeps track of the minimum health required to reach an infinite health vertex from each vertex. The first case is to find the prefix minimum value of the path from $s$ to $t$. It is easy to see that the prefix minimum value is either the entire path or the entire path excluding the vertex $t$. Otherwise, there must be infinite health on the path, which can b...

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JOI Open Contest 2019 Hello everyone! [JOI Open Contest 2019](https://contests.ioi-jp.org/open-2019/index.html) will be held on [July 14. (04:00-09:00 UTC)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+Open+Contest+2019+-+Round1&iso=20190714T04&p1=1440&ah=5) and [July 14. (10:00-15:00 UTC)](https://www.timeanddate.com/worldclock/fixedtime.html?msg=JOI+Open+Contest+-+Round2&iso=20190714T10&p1=%3A&ah=5). As the tasks in these rounds are the same, you can participate in whichever round you like. The contest duration is 5 hours and there will be 3 tasks. Each submitted source program must be written **only** in C++. Problem statements will be provided both in Japanese and in English. You can find the details in [the contest page](https://contests.ioi-jp.org/open-2019/index.html). The past contests are also available in [this page](https://contests.ioi-jp.org/). Since the judge server isn't available after the contests, please download the testcases when you want to test your code. ...

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When will the ratings of problems and cheaters be calculated? ###### Update: The ratings for problems ( not cheaters) has been updated. Thanks to the codeforces team! ============================================================ The ratings for [Nebius Round 2](https://mirror.codeforces.com/contest/2211/ratings) and subsequent Codeforces Rounds have not been recalculated yet. A total of $3462$ cheaters are still gaining rating increases. It has been **30** days and 9 contests since the Nebius Round2, yet the ratings still haven’t been rolled back and recalculated. For example:   All usernames preceded by two asterisks are cheaters. Note: $$ 3462=(11983-11649)+(15059-14222)+(21856-20832)\\ +(15059-14799)+(11878-11787+4)+(12694-11782) $$

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Codecracker 2015 **Update2**: The contest duration for round 2 has been extended to 3 hours! **Update**: The details of **Round 2** have been added! Please check :) To upsolve questions of Round 1, head over to our site and try the questions on the practice contest. Presenting, the flagship event of **MUKTI -- CODECRACKER**! hosted by National Institute of Technology, Durgapur. Codecracker is a competitive coding event, drawing participation from over 50 countries. The contest will be governed by ACM-ICPC rules. Cash prizes worth **25000 INR** on offer. The competition is cut-throat. Do you think you have what it takes? Come. Code. Challenge yourself against the best and prove your mettle. Log on to: http://codecracker.in/index.php/login Round1: Timings: [21:30 IST](http://www.timeanddate.com/worldclock/fixedtime.html?msg=Codecracker&iso=20150130T2130&p1=54&ah=2&am=30) Duration: 2.5 hours Round2: Timings: [21:30 IST](http://www.timeanddate.com/worldclock/fixedtime.html?msg=Cod...

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Hackwithinfy round2 problem. This a question from a recent contest which ended few hours ago. **Problem statement** You are given a tree consisting of N vertices,What is the minimum number of vertices that should be removed such that all the remaining parts of the initial tree contains less than K vertices. **End** Since the verdict was hidden during the contest I am not sure whether my approach is correct. My approach goes as follows: 1. Sorting the vertex on the basis of number of adjacent nodes. 2. Picking each vertex one by one and running the dfs to collect exactly (k-1) vertex and marking them visited. 3. If a path has already less than K vertices ignore it or ,increment the answer. If it's a common problem please point out as I have just started learning graphs.

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HackWithInfy Round2 (Doubt) Hey Guys, there was a question in Round 2 of the HackWithInfy Contest which I feel is quite nice and I wasn't able to think of any possible solution to it. So the question goes like that:- We have defined a function f(x) = sum of all the digits of x. Now, 0 <= i <= N 0 <= j <= N We have to count how many pairs are there which satisfy the condition that f(i) + f(j) is a prime. Constraints:- 0 <= N <= 10^50 Example:- 1) N = 2 pairs = 2 2) N = 3 pairs = 4 Can anyone suggest some possible method to solve this question??

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Codecracker 2015 Round 2 Round 2 of CODECRACKER hosted by NIT Durgapur shall start at 21:30 IST today!! Don't worry if you missed out on all the fun yesterday, you can still win prizes upto _**25,000 INR**_. The results shall be decided by the cumulative performance in both the rounds for deciding the prizes. The questions of Round 2 are going to be more challenging and interesting and so we've decided to increase the time to 3 hours for the competition. Log on to http://codecracker.in and follow https://www.facebook.com/events/867191919969063/ for updates :) Round2: Timings: [21:30 IST](http://www.timeanddate.com/worldclock/fixedtime.html?msg=Codecracker&iso=20150131T2130&p1=54&ah=3&am=0) Duration: 3 hours

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How to solve Codejam 2022 Round2 B? I don't understand why there are xt number of colored pixels between y=x and y-axis in Analysis. Can someone explain Analysis in more detail? Or can you tell me another solution?

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