View source for Codeforces

'''Codeforces''' is a [[competitive programming]] website<ref>{{Cite website|url=https://mic.com/articles/186412/north-korean-college-coders-beat-stanford-university-in-a-2016-competition-heres-why-that-matters#.9baJjoyF5|title=North korean college coders beat Stanford University in a 2016|website=mic.com|quote=Codeforces — a Russian competitive coding site with contestants from around the world}}</ref>. It was created and is maintained by a group of competitive programmers from [[Saratov State University]] led by Mikhail Mirzayanov. Since 2013, Codeforces claims to surpass [[Topcoder]] in terms of active contestants <ref>{{Cite website|url=http://codeforces.com/blog/entry/10148|title=Codeforces results 2013|website=codeforces.com}}</ref>. As of 2017, it had more than 600 000 registered users <ref>{{Cite website|url=https://codeforces.com/blog/entry/56831|title=Codeforces results 2017|website=codeforces.com}}</ref>. Major online judges like Codeforces are used by top sport programmers like [[Gennady Korotkevich]], [[Petr Mitrichev]] or [[Makoto Soejima]], but also non-celebrity programmers interested in furthering their careers<ref>{{Cite website|url=https://www.bloomberg.com/news/features/2015-09-25/the-jocks-of-computer-code-do-it-for-the-job-offers|title=The jocks of computer code do it for the job offers|website=bloomberg.com}} </ref> <ref>{{Cite website|url=https://luckytoilet.wordpress.com/tag/codeforces/|title=Are programming competitions a good use of time?|website=wordpress.com}}</ref><ref>{{Cite website|url=http://www.lus.ac.bd/news/student-of-cse-dept-becomes-candidate-master-in-codeforces/|title=Student of CSE Dept. becomes Candidate Master in Codeforces|website=www.lus.ac.bd}} </ref>. 

== Overview ==

The Codeforces platform is typically used when preparing for competitive programming contests<ref>{{cite AV media |title=Difference between HackerRank, LeetCode, topcoder and Codeforces |medium=Youtube |language=English |url=http://www.youtube.com/watch?v=J267bz_G7xE&t=1m45s |time=1:45 |quote=Difference between HackerRank, LeetCode, topcoder and Codeforces: "Topcoder and Codeforces is a website that's typically used when preparing for actual competitive programming contests" |ref= }}</ref><ref>{{Cite website|url=http://aipo.computing.dcu.ie/training|title=All-Ireland Programming Olympiad Training|website=aipo.computing.dcu.ie|access-date=2018-10-26|archive-date=2019-12-18|archive-url=https://web.archive.org/web/20191218032907/http://aipo.computing.dcu.ie/training|dead-url=yes}}</ref><ref>{{Cite website|url=https://turing.cz/tom/acm.html|title=ACM-ICPC training at FIT CTU|website=turing.cz|language=Czech}}</ref><ref>{{Cite website|url=https://medium.freecodecamp.org/coding-interviews-for-dummies-5e048933b82b|title=The 30-minute guide to rocking your next coding interview|website=medium.freecodecamp.org|quote=CodeForces questions are more similar to questions in competitive programming}}</ref> and it offers the following features:

* Short (2-hours) contests, called "Codeforces Rounds", held about once a week<ref>{{Cite website|url=https://cses.fi/book/book.pdf|title=Competitive Programmer’s Handbook|website=cses.fi|quote=At the moment, the most active contest site is Codeforces, which organizes contests about weekly.}}</ref><ref>{{Cite website|url=http://tildeweb.au.dk/au121/code/|title=Algorithms programming competitions|website=tildeweb.au.dk}}</ref>
* Educational contests (2-2.5 hours, with 24 hours hacking period<ref>{{cite journal
| last       = 
| first      = 
| last2      = 
| first2     = 
| date       = 2018
| title      = Grading Systems for Algorithmic Contests
| url        = https://ioinformatics.org/journal/v12_2018_159_166.pdf
| journal    = Olympiads in Informatics
| volume     = 12
| issue      = 
| pages      = 159–166
| doi        = 10.15388/ioi.2018.13
| access-date = 
}} </ref> ), held 2-3 times per month;
* Challenge/hack other contestants' solutions;
* Solve problems from previous contests for training purposes;
* "Polygon" feature for creating and testing problems;
* Social networking through internal public blogs.

Contestants are rated by a system similar to [[ELO]]. There are usually no prizes for winners, though 2-3 times a year special contests are held, in which top performing contestants receive T-shirts. Some bigger contests are hosted on Codeforces base, among them "The Lyft Level 5 Challenge 2018", provided by [[Lyft]] <ref>{{Cite website|url=https://blog.lyft.com/level-5-challenge-terms/|title=Lyft 2018|website=blog.lyft.com}}</ref> or "Microsoft [[Q Sharp|Q#]] Coding Contest — Summer 2018" provided by [[Microsoft]] <ref>{{Cite website|url=https://cloudblogs.microsoft.com/quantum/2018/06/27/challenge-your-skills-in-the-microsoft-q-coding-contest-summer-2018/|title=Microsoft Q# Coding Contest|website=cloudblogs.microsoft.com}} </ref>.

Contestants are divided into ranks based on their ratings. Since May 2018, users with ratings between 1900 and 2099 can be rated in both Div. 1 and Div. 2 contests. At the same time, Div. 3 was created for users rated below 1600.The table below was up-to-date on 2018-05-15 <ref>{{Cite website|url=http://codeforces.com/blog/entry/59228|title=Codeforces: Updates in rating and rounds|website=codeforces.com}} </ref>.

{| class="wikitable"
!Rating Bounds
!Color
!Title
!Division
!Number
!Number (by color)
|-
|≥ 3000
|Red
|Legendary Grandmaster
|1
|14
| rowspan="3" |261
|-
|2600 — 2999
|Red
|International Grandmaster
|1
|90
|-
|2400 — 2599
|Red
|Grandmaster
|1
|157
|-
|2300 — 2399
|Orange
|International Master
|1
|134
| rowspan="2" |792
|-
|2100 — 2299
|Orange
|Master
|1
|658
|-
|1900 — 2099
|Violet
|Candidate Master
|1/2
|2101
|2101
|-
|1600 — 1899
|Blue
|Expert
|2
|5186
|5186
|-
|1400 — 1599
|Cyan
|Specialist
|2/3
|10408
|10408
|-
|1200 — 1399
|Green
|Pupil
|2/3
|15584
|15584
|-
|≤ 1199
|Gray
|Newbie
|2/3
|6250
|6250
|}

== History ==
Codeforces was originally created for those interested in solving tasks and taking part in competitions <ref>{{Cite website|url=http://news.ifmo.ru/en/education/official/news/7861/|title=Codeforces Founder Will Teach Web Development at ITMO|website=news.ifmo.ru}} </ref>. The first Codeforces Round was held on the February 19, 2010 with 175 participants. As of the end of January 2016 over 300 rounds were held, with over 5000 registered competitors per round on average. Before 2012 Codeforces Rounds were titled "Codeforces Beta Rounds" to indicate that the system was still under development. 

== Use in Academia == 
Codeforces are recommended by many universities<ref>{{Cite website|url=https://web.stanford.edu/class/cs97si/01-introduction.pdf|title=Introduction-CS 97SI-Stanford University|website=web.stanford.edu}}</ref><ref>{{Cite website|url=http://www.cse.unsw.edu.au/~cs4128/18s1/lectures/1-introduction.pdf|title=Introduction,COMP4128 Programming Challenges, School of Computer Science and Engineering, UNSW Australia|website=cse.unsw.edu.au}}</ref><ref>{{Cite website|url=https://turing.cz/tom/acm.html|title=ACM-ICPC training at FIT CTU|website=turing.cz|language=Czech}}</ref><ref>{{Cite website|url=https://medium.freecodecamp.org/coding-interviews-for-dummies-5e048933b82b|title=The 30-minute guide to rocking your next coding interview|website=medium.freecodecamp.org|quote=CodeForces questions are more similar to questions in competitive programming}}</ref>. According to [[Daniel Sleator]], professor of [[Computer Science]] at [[Carnegie Mellon University]], competitive programming is valuable in computer science education because competitors learn to adapt classic algorithms to new problems, thereby improving their understanding of algorithmic concepts. He has used Codeforces problems in his class, 15-295: Competition Programming and Problem Solving <ref>{{Cite website|url=https://contest.cs.cmu.edu/295/f16/|title=15-295: Competition Programming and Problem Solving, Fall 2016|website=cs.cmu.edu}}</ref>.

== Hello Barcelona ACM-ICPC Bootcamp ==
In February 2017, Codeforces supported the Hello Barcelona ACM-ICPC Bootcamp, a training program for students preparing for the [[ACM International Collegiate Programming Contest]]. Codeforces founder and CEO Mike Mirzayanov participated as a coach for the program, which invited 150 university students<ref>{{Cite website|url=https://www.gsnmagazine.com/article/47867/barcelona_bootcamp_feature_instructors_moscow_phys|title=Barcelona Bootcamp|website=gsnmagazine.com}}</ref>. The second Barcelona bootcamp which was held Sept 27 to Oct 5, 2017 had participants from 25 different universities including [[Georgia Institute of Technology]], [[Technical University of Munich]] or the ACM-ICPC winners [[ITMO University]]<ref>{{Cite website|url=https://in.harbour.space/icpc/acm-icpc-hello-barcelona-bootcamp-autumn-2017/|title=Companies making ACM-ICPC bootcamp available for everyone|website=in.harbour.space}}</ref>.

== Rankings ==
=== Result by country ===
{| class="wikitable" style="text-align:left"
|-
! Country
! style="text-align:center" | Rating
|-
| {{flagicon|RUS}} [[Russia]]
| style="text-align:center" | 3058
|-
| {{flagicon|POL}} [[Poland]]
| style="text-align:center" | 2993
|-
| {{flagicon|CHN}} [[China]]
| style="text-align:center" | 2991
|-
| {{flagicon|KOR}} [[South Korea]]
| style="text-align:center" | 2949
|-
| {{flagicon|JPN}} [[Japan]]
| style="text-align:center" | 2910
|-
| {{flagicon|USA}} [[United States]]
| style="text-align:center" | 2817
|-
| {{flagicon|BLR}} [[Belarus]]
| style="text-align:center" | 2801
|-
| {{flagicon|UKR}} [[Ukraine]]
| style="text-align:center" | 2749
|-
| {{flagicon|TWN}} [[Taiwan]]
| style="text-align:center" | 2681
|-
| {{flagicon|CAN}} [[Canada]]
| style="text-align:center" | 2636
|-
| {{flagicon|ROM}} [[Romania]]
| style="text-align:center" | 2606
|-
| {{flagicon|HKG}} [[Hong Kong]]
| style="text-align:center" | 2461
|-
| {{flagicon|VIE}} [[Vietnam]]
| style="text-align:center" | 2457
|-
| {{flagicon|IND}} [[India]]
| style="text-align:center" | 2437
|-
| {{flagicon|IRN}} [[Iran]]
| style="text-align:center" | 2432
|-
| {{flagicon|CRO}} [[Croatia]]
| style="text-align:center" | 2431
|-
| {{flagicon|CZE}} [[Czech Republic]]
| style="text-align:center" | 2414
|-
| {{flagicon|KAZ}} [[Kazakhstan]]
| style="text-align:center" | 2383
|-
| {{flagicon|IDN}} [[Indonesia]]
| style="text-align:center" | 2372
|-
| {{flagicon|GER}} [[Germany]]
| style="text-align:center" | 2348
|}<ref>https://codeforces.com/ratings/countries</ref>

== See also ==<!-- PLEASE RESPECT ALPHABETICAL ORDER -->
* [[ACM International Collegiate Programming Contest]] 
* [[CodeChef]]
* [[CodeFights]]
* [[Facebook Hacker Cup]]
* [[Google Code Jam]]
* [[HackerRank]]
* [[Online judge]]
* [[SPOJ]]
* [[Topcoder]]
* [[UVa Online Judge]]

== References ==
<references />

== External sources ==
* [https://codeforces.com/ Official website]
* [https://cfviz.netlify.com Codeforces visualizer] {{Webarchive|url=https://web.archive.org/web/20181026222402/https://cfviz.netlify.com/ |date=2018-10-26 }}