This is the list of frequently asked questions concerning Codeforces work and answers to them.
- What is Codeforces? What kind of a site/resource is it?
- What should I do to participate in contests? Is preliminary registration required?
- What are the rules of the contests?
- What languages can I use to solve problems here? Are there any problem solving examples?
- I would like to organize a Codeforces round with my problems. What should I do to achieve that? Are the authors entitled to get any reward?
- What other rules are on Codeforces?
- Which technical details are useful to know about the Codeforces' testing system?
- What are the rating and the divisions?
- What is contribution?
- What blog posts are useful to take a look at?
- I've noticed that the site contains the solutions of all the contestants and the previous contests' tests. How is it allowed to use them?
Questions and answers:
- What is Codeforces? What kind of a site/resource is it? Codeforces is a project joining people interested in and taking part in programming contests. On one hand, Codeforces is a social network dedicated to programming and programming contests. On the other hand, it is a platform where contests are held regularly, the participant's skills are reflected by their rating and the former contests can be used to prepare. Codeforces constantly develops and we plan to improve the platform to give the participants the opportunity to organize their own contests, filling the project with learning content, developing Codeforces as a training and learning platform.
- What should I do to participate in contests? Is preliminary registration required? Contests are regularly held on Codeforces. Participating in them is free and open to everybody. Every month we organize approximately six contests. To participate, you have to be registered on the site (if you have an OpenID or a Gmail account, then you won't even have to memorize the password) and register for the oncoming contest. Make sure that you are present in the list of the users, registered for the contest, before the registration ends. Usually, if you can't take part in the contest officially (e.g. if it's the contest for the second division and you are in the first one), then you can register for the contest to participate out of competition.
- What are the rules of the contests? They are usually held according to the original Codeforces rules. If it is specially stated, then the International Collegiate Programming Contest rules ACM-ICPC or some other modifications can be used. In brief, on the contests held by Codeforces rules you write solutions to the problems that are tested during the contest on a very small number of tests. Those who have passed that set of solution tests, their authors can block (refuse to resend the solutions of this task in future even if they find a mistake). Such authors receive the opportunity to look through the sources of other contestants, look for mistakes there and suggest the tests on which these solutions do not work. Thus, you can hack somebody else's solution and earn points through it.After the contest all the solutions that have passed the pretests and haven't been hacked are tested on the final set of tests. The value of a task decreases during the contest (the faster you solve the problem, the more points you receive), unsuccessful hacks take off the points and the successful ones add them. Please take a look at the detailed version of the rules before participating in the contest.
- What languages can I use to solve problems here? Are there any problem solving examples? Read the post "On the technical details on Codeforces".
- I would like to organize a Codeforces round with my problems. What should I do to achieve that? Are the authors entitled to get any reward? Do you want to organize a round? That's great! We are very pleased to hear that. Please, read the post.
- What other rules are on Codeforces? We don't have a clear Great Codeforces Code of Conduct. However, of course, here you should behave in accordance with traditional rules of behavior in public places and theme groups. The following rules are, of course, necessary to follow:
- Don't create more than one account, if you have forgotten the password, use the password reminding system.
- Do not use harsh, rude or misleading handle.
- Do not use anybody photo except yours. It is uncultured and could confuse Codeforces users.
- Don't be rude, don't insult other participants and administration, try to be polite and pleasant to communicate with.
- When you take part in individual contests, don't talk about the problems with other contestants, don't use somebody else's code or insert it into your solutions. If the contest is a team one, discuss the tasks only with the teammates.
- Don't try to destabilize the site's and the checking system's work. Your programs should only interact with the console (for the problems with the standard input and output) or the input and output data files.
- Don't publish or spread your solutions and solution ideas during the contest.
- Which technical details are useful to know about the Codeforces' testing system? The Codeforces system resembles classical Online Judges. The solutions are tested on the tests prepared beforehand (or the hacks suggested by other participants). As a result, you receive verdicts, the meaning of which is clear from the title. It should be specially noted that Codeforces does not have the "Presentation Error" verdict, this situation is regarded as "Wrong Answer". All the suspicious verdicts (testing error etc.) are not considered while evaluating the results. That is also true for the solutions that had fallen on test 1 (in the problems containing more than one test).
- What are the rating and the divisions? When the contesters take part in Codeforces contest, they raise or lower their rating that reflects their ability to solve the tasks. The rating is a modification of Elo rating, several details can be read in a fuller form. According to the rating, the contestants are split into two divisions: the second one (the weaker one, amateurs) and the first one (the stronger one, pros). The contestants who don't take part in contests and those whose rating is below 1900 belong to the second division. The 1900+ rating means that you're part of the first division. Usually two types of contests are held on Codeforces: for the second division contestants (the first division contestants can take part there out of competition) and for both divisions. The first contest type contains simpler and learning-oriented tasks.
- What is contribution? The votes for the posts and comments of a user change his/her contribution. The contribution is intended to show the usefulness of the community user. The contribution counting system is imperfect; in future the rules for its calculation will be changed.
- What blog posts are useful to take a look at?
- I've noticed that the site contains the solutions of all the contestants and the previous contests' tests. How is it allowed to use them? In fact, we publish materials from the past contests and they can be used, for example, for individual lessons. Using the materials on other Online Judges, public contests, etc. is prohibited. Be sure toread the license before using the materials.In order to view someone else's solution, just click on his id on the page "Status". From the page with the list of tasks you can go to the list of correct decisions for the given task. At the bottom of the "Status" pages (and others with the lists of decisions) there is an option of sorting the solutions on different criteria.
Помощь
I QUIT !!!!
I would like to register about 2-3 weeks ago, and I clicked on the register button, but I wasn't logged in, so Login window appeared and I logged in and after that I forgot to register, I thought I registered..Few hours later I started to solving the problems and after the first solved problem I realized I didn't register.. I know it's my problem, and my mistake.. So I just would like to know, any reason why registration is required? (example participate limit )
TANX
What results in Denial of judgement?
It's usually just some random server error. If you wait and then resubmit, it should judge correctly.
Are there rules for pictures? The part in the profile editor says that your face must be clearly visible, but there are plenty of users with pictures that do not contain them.
What is the best way to find an editorial, say for e.g. if I am looking for editorial of Round #88, how can I find it quickly?
You can find links to practically all editorials in this page.
Links in "list of frequently asked questions" in the beginning of the blog has to be updated — it's not working.
I tried this link http://codeforces.net/blog/entry/1336#q8 and nothing happened.
Can you add a feature to see friend's friends, like facebook? That would be very nice.
Why the flags of my solved problems disappear? How can I make it appear again?
It might prove to be useful if some comparison tool(s) can be implemented -- something like https://www.otinn.com/topcoder/al/comparer.php or http://topcoder.manabase.com/graph.php, except in CodeForces setting, instead of TopCoder.
Interesting tools, but most difficult for me is to beat myself :-D
I want to change my HANDLE. How can I do this? Thanks for help.
When I'm entering to Esc>Settings>Handle there is message : "The page is temporary blocked by administrator. We are doing it because of increased load. Do not panic, we will unblock the page soon. Thank you for your understanding."
and When it will unblock? Thanks for help :D
This opportunity was a present from admins in the first days of new year.
hello Mr.Mirzayanov How can i delete my team ?
KILL IT WITH FIRE
I have two problems. The first is where to complain about the problems with the site in general? Since I could not find a forum or a place to file my complaints I am writing it here in the FAQs. I don't know whether this has been brought up before or not, but those tags in the problems virtually make this site unusable for practice purposes. Most often knowing what method to use to solve a problem is half the solution and it is clearly right there for everyone to see! Can we make them hidden by default please (it should be shown only after a 'user action' like clicking an 'expand' button)?
You can disable tags for unsolved problems on the settings page.
It is possible, you can adjust the settings in the user profile.
Can I download the test data of some problems? How?
you cant.
how to delete a favourite submission from favourites?
How did you have added it to favs? Unfavourite it in the same way.
Click 1365856 and remove a star.
And don't post so huge screenshots next time. ;)
How to download all of my submissions (or just Accepted)?
How must be format of the solution ? how can i get inputs and put output in solution for example in C++ language? I could not found any help to the above questions
All your code must be in one .cpp file.
It must read data from standart input (stdin).
It must write data to standrat output (stdout).
For example:
Is there any way to delete (particular) talk(s)?
Hi, If I virtually participate in a contest after it was officially held, the final result will affect my rating ?
no
Can you add go as an official language? http://golang.org
Is there any mailing ID for help. Headquarters e-mail ID???
send message to Headquarters (here)
I do it and I think i get my answer
Could I ask is there any way I can see the details of my marked friends?
the numeric list is wrong. .... so uncomfortable.
Why downvoting? It really is.
UPD: it's quite cool to see that GCD's comment was upvoted so lot (at least it became positive) after this comment but myself I was downvoted so much...
is there a long term calender for codeforces .. like topcoder's one ?. or how to know the time for next rounds and other contests along the month or along the year ? :)
thanks in advance :)
Can DIV 1 users who participate "out of competition" in only DIV 2 contests, hack others' solution?
Yes but only div1-ers
And are they rated for div1 users? Asking for a friend.
I've got a problem with the site: is it possible to check out my own past submissions for a particular problem?
How can we see all the solutions of a problem submitted in a specific programming language ?
Why is my code skipped? (problem D contest 211 div 2)
same problem here. can anybody explain what the 'skipped' verdict means. I can't find anything on it.
I have a big question. How do I delete my account (or change my handle) ? I am really unhappy with the name I got. (I know I chose it but I'm sorry).
Anticipated thanks. Lawliet
I don't think it is possible to change your handle. But since you haven't participated in any contests yet, why not just create a new account? Your handle isn't that bad btw :P
I don't want to create a new account because I need a new e-mail, and if I create an e-mail just for codeforces, I will end up missing all of the e-mails I get.
Mail programs (gmail, as an ex.) can collect mails from other email addresses
You can change your handle near January the First. A week for this operations always is given at New Year.
Hello,
Can someone please tell me when will I be able to change my handle? I really don't want to miss my chance.
Anticipated thanks, Lawliet
u can change it anytime till the 10th January 2014.
Isn't there something I can do now? I don't want to wait another year... sadface
Please, just stop moaning and start to solve problems.
how to add friends, so that we can see their rating??
Click on "Star" symbol in your friend's profile.
Hello How to organizers of the mail or memmage?
I'm sorry for my poor English.I mean how to send mail to the codeforces Official website organizer.
can someone help me on, how to download problem statements from the site??
If there are not file of problem statements in contest, you can copypast them or take a screenshot
The shortcuts to the questions are not working.
I don't need this ID any more. Will anyone delete it?
pspburner and sinkey ask same question,isn't it
how to change my register email address??
try it here: http://codeforces.net/settings/general
Right now I log in with my Gmail account. If I want to change it to have a username and password to log in, how can I do it?
Use "forgot password?" Link on the login page.
Could I delete my account ?
HIiii....
I am using codeblock to run c++ program...
My program gives correct result in my system.. but failed in codeforce Compiler. Any solution.. How I handle this..???
In your program you allocate an array
b
of lengthp
, but then inb[(a[i]%t)]
you access it as if it was an array of lengtht
. This can fail ift > p
.How can we delete an account in codeforces?
You cannot delete an account in codeforces otherwise every person who has a lower rating than the starting rating of 1500 would be tempted to delete his current account and create a new account to start afresh .
you dont need to delete your account to have a new account ! you can get new without deleting .
But members of Codeforces insult people who use multiple accounts and thus people are hesitant of creating new accounts.
I really don't want to see the problem tags before I think about the problem.** How can I hide the appearance of the problem tags?** The tags have a bad influence on my independence of solving prosems.
Here /settings/general is a checkbox (Show tags for unsolved problems). Just uncheck it.
If any person does not sucessfully solved any one problem in codeforces match Will it rating changes??
Rating will change
Rating can stay unchanged. About rating.
Is it possible to make someone's code private??
As far as I know, our code is public to others. We don't have access to hiding our code. I think this is very good for us to learn from others.
Hey Guys,
I think there is a problem with the links when you click on them they don't point to the answer I checked the page source file it seams that the
id
they are pointing to is not assigned to the answer<li>
Can anyone check :)
Can i participate in div2 contest if my rating is greater than 1700 ? and vice versa ?
No.
you can participate in div2 if there is no round div1
Hi,Mike Mirzayanov
I Designing some problem for contest!
How I can produce a contest in CF?
thanks
When I was blue I asked them this question and they answered "You should be at least yellow." ;)
Hi everyone, I'm new here and I've met some serious problems like this one I submitted (tested in custom test) my code in c++ and it returns a wrong answer (1) but when I test my code in my compiler (codeblocks) it return the correct answer which is (2)
how does this happen ? is it my mistake or some kind of bug in my compiler or codeforces's ?
please help me !
(160A Twins)
Because of some problems I had with logging in the account with ruhanhabib39 handle, I created another account(ruhan.habib39). Now I want to delete the ruhanhabib39 account. How will I delete it?(I was unable to login in that account).
You may want to change Gerald to Max in this faq
Is there any way to change my username?
I think you'd better wait for New Year – you'll definitely get such an opportunity :)
Please let me know if this is not the right place to ask questions.
I have a question about virtual contests. Me and some of my friends are planning to compete on the previous div 2 rounds. As I understand, each of us will have to simulate the virtual contest individually and then compare our results. Is there a better way for this? I mean can we create a room or group and compete there such that leaderboard or scoreboard gets updated as would happen in a real contest? I hope I made my point clear.
Help is appreciated. Thanks!
Sir, My code gave correct output in ideone online judge, but gives a different output here, what should I do, Submission id: 11656468
Dont use pow() for integer calculation.
11664178
yes i hace the same problem and literally i have no idea what's happening
Couldn't open codeforces.com in Shanghai China these days,,,,,
i've got a problem that gives me an answer on my computer and with the same input it gives another answer when i send it here. the problem is kefa and park. can anybody help me please?
What is the rating criteria?? How Does attending contests and solving problems change rating?
This may help you: Open Codeforces Rating System [updated on October 2015]
I am unable to see the image in — http://codeforces.net/contest/599/problem/A. Using a chrome browser and images in other sites even current home page for codeforce looks good. Please help
Here it is:
thanks
why i can't see the problem's photo? link here http://codeforces.net/problemset/problem/599/A
How much space is available for any problem in the contest?
Hi, I am using C# but when I submit an answer that write a double value it is printed by using comma (,) instead of dot (.), resulting in WRONG_ANSWER. I use Console.WriteLine( a_double_var );
Any idea? For example, I got this when submitting #14827895:
My submission finally got accepted after I changed the output statement to:
It would be better if we don't have to specify the CultureInfo explicitly though.
I changed my handle to "I_love_CC". In the profile page it's changed, but it still remains the old handle "zkx06111" in the room I was competing.
Help... How to change my handle as New Year Gift? I am using Codeforces with GMail, I have no password. When trying to change it asks my password.
restore your password
thank you
The information about rating threshold between Div 1 and Div 2 is outdated. It is now 1900 instead of 1700.
I have an issue in assessing my last submissions
MikeMirzayanov
You wrote it in C++ but the single acceptable language is J,what is the problem?
@admin i just wanted to request codeforces team to improve their regular expression which give warning about syntax for ex. when we use printf("%lld",sum); then it suggest to use cout but it also give the same warning when i am using //printf("%lld",sum); so it should not warn me in this case .
What'd happen if I'm unable to participate in a contest after registration?
If you don't submit any problems, it will count as if you didn't participate in the contest.
is uploading your code only way to submit the answer? or os there any way we can write and submit the code on the site itself.
You can go to the submit code tab to copy paste your code there. I'd recommend against writing your code in browser, but the custom test tab allows you to write and test your code.
I recently favourited a question here on codeforces by clicking the star near it. But now I forgot the problem code is there anyway to access the problem?????
You can find "FAVOURITES" at the top of your profile.
Is there any problem using cin.sync_with_stdio(false) and cout... cause i got runtime error on the last contest.
Dear Codeforeces support team
My handle name is sai108710. This is very weird. I had created it mistakenly. I want to change it as I don't want to create a new one. How can I? I am looking for codeforces support team email address. Would anyone kindly provide it, please?
You can change your Codeforces handle once a year, usually during Christmas Holidays. So, you have to wait until December.
Hello noelnadal,
Great to share your knowledge. Ya, I know I can change it at December but not sure on which days. On those days, does codeforces active some links/ setting to the users?
Yes, on the home page you will see a blog post like this one: http://codeforces.net/blog/entry/49425. It will mean that the feature is available again.
Hello. I have problem with double cola problem(code:82A) I think that the third test case is wron becuase i tired it using a pen and paper. I need help about that!?!!!;!;
How can I change my nickname?
wait until January 2019.
But when I registered, it said that I could change my nickname this week.
You can only change your nickname in the first 10 days of new year.
How to retrieve the account number? My friend's account number was stolen by someone else a few days ago. And his password and email have been modified so he couldn't get his account. I would be very grateful if he could get your help! MikeMirzayanov
https://codeforces.net/blog/entry/61363
guys,i'am new here.will points be rewarded for solving psets?. what are the uses of solving those psets?. does taking part in contests the only way to get rating?.
yes
i have a problem when i want to submit a code it takes so many time and nothing appear ans i should reload the page 2 times. after that when i submit my code,the status page appear does anyone else have the same problem? what should i do?
Dear Codeforces Team,
I would like to see all the tests inputs for problem 608B (Hamming Distance Sum). I've just submitted a solution that fails on test number 9. However, when I inspect the statistics of my submission, input data for test 9 is incomplete (truncated).
Please, is there any option to get the testing data?
Thank you very much!
Solution doesn't fit in an
int
. Uselong long
instead. You could have figured that out by looking at any other submission or by simply noticing that the correct answer for that case has 10 digits.How can i see my progress?
Use tools such as https://cfviz.netlify.com/ :)
Please use HTTPS for http://m1.codeforces.com, http://m2.codeforces.com, and http://m3.codeforces.com !!
agree
In one of the question, i got a runtime error on a particular testcase (13th) when i submitted it on codeforces
but when i copied the same code and run it on my IDE as well as online, output is coming.
what could be the problem?
What exactly are the system test cases? I understand that it includes all successful hacks. But, can the problem author add tests, which are in the system tests, but not in pretests?
Yes. Usually, only a small part of all tests are in pretests.
Educational Codeforces Round 73 [Rated for Div. 2] problem no.2 my solution got accepted during the contest while it was not able to pass even the testcase given in the question. Do you think it should have passed the pretests? That created confusion. If the at that time the contest would have said that it is wrong on testcase 1. I might have corrected it. This is wrong codeforces.
How would I contact site admins? Or to be more exact in this case, how can I report a problem? I got this status in my submission: "Probably, the solution is executed with error 'uninitiaized value usage' on the line 14" Pretty sure it's a spelling mistake, and should be 'uninitialized', right?
Hello everyone, can anyone helps me explaining what is runtime_error in contests? I get the answer on my machine in CPP, but when I submit the same code result is RUNTIME_ERROR.
If you're talking about this, return 0 not 1
My rating is 1629 but still it is showing me as a specialist instead of expert is this a bug? or it wll gets fixed?
any problem doesn't open show massege "can't read or parse problem descriptor " How solution this?
There is a serious issue in code forces system testing. In codeforces round 612, my solution got time limit error.I just wrote the exact code of a function in the main function instead of calling it and re submitted it.Right now,it got executed correctly. This is ridiculous.Because of this my rank went way down.If there is any user support,I would like to complain about it.
I see that for Div 2 only contests, purple coders also officially take part in the contests. But this FAQ says, your rating need to be < 1900 to take part in div 2 contests.
These rules are a little outdated. Nowadays all Div 2 only and Educational rounds are rated for < 2100.
I had a given a contest of Div 3 it is not showing in my contests that i participated Moreover i cant find my name in ranklist My one sol got accepted
http://codeforces.net/submissions/MasonMount19
My submission in the CF1111E is “Denial of judgement” Can anyone has the power of the admin help me fixed it? thanks very much!
[problem:A. Buy a shovel] I have a problem , when I send the code to the test the output appears different form the actual output in my computer . For example : the test appears number 10 .But, in my computer when I run a code the number 9 appears in the console application window which is correct.
I wonder if codeforces can provide an API that can implement the following functions? Return the rank page of friends in real time through the contest ID and personal key. Or maybe you've done it but I haven't found it. I hope you can help me,thx.
One more thing, the number of people who passed the problem A,B... of the ongoing competition.
For the second one, you can check the dashboard with the problem list of the contest. On the right side of each problem there is a count of solves.
Thank you. You're right. But what I want is an API excuse. Now that I've implemented it through an existing API, thanks again
sir,i am unable to get rating??? why,is this happening??
you have to participate in official rounds to get ratings
I have started participating.
April Fools round was not rated.
And many contest also I have attended. But, their is no rating.
According to your profile you have solved problems from past contests. You have to participate in official rounds in the official time to obtain rating
Sir, why I am not getting rating.
check your submissions page if it shows all of submissions you have done
how to change handle? i wanted to change.
You have to wait for next January
How to get testcases for a certain problem? So that I can download it and test it offline.
Sir,for python users time constraints should be 5*x.as it is not fair to have similar time constraints for c++ and python users when python is approximately 5 times slower than c++
Python is easy to learn and master as compared to c++, so it is unfair for c++ users to learn c++. Also in c++ we have to write lengthy codes as compared to python...so you should face some disadvantages of using python..so that it does not turn out unfair for c++ users.
I can not see my submissions..As a result when i submit any problem i can not know whether it is accepted or not.Please help me...What should i do now/?
https://codeforces.net/submissions/Fahim_Anin
I participated in my first rated contest yesterday and got this message today :
Attention!
Your solution 81772855 for the problem 1359B significantly coincides with solutions fireboy009/81772855, fireboy009/81773786.
The two solution that it says coincides are the same solution. Also, both solutions are mine.
There must be a bug in the plagiarism checking system that is checking my own solution with my other solutions.
Please look into it. MikeMirzayanov
BUGS IN GNU C++17 (64)
In Educational Round 88 Problem C I have submitted my code using GNU C++17 (64) compiler and it gives WA on test 4. But today I have submitted the same code using C++17 compilers it is accepted. I have made a blog entry for the same where you find attachment of codes.
Please look into it MikeMirzayanov
Hey I am completely new to this platform.Can someone tell when will my ratings change for the first time. I have also participated in a contest recently but my ratings are still unchanged as always.
Problem Connecting Facebook id to cf account, plz fix this.
Can i have two accounts on codeforces ... One for practice and one for contests???
no, you can't
Okk thankss
It's illegal, read question 6
i have submitted the code,but still i got compilation error,but i got rating for that . how is it possible ?? they will verify these comilpilation errors also .. please answer this ??
Your rating will change if you submit a solution inside a contest while it's running, regardless of it's verdict.
the written code may be any thing irrespective of the question ,still we will get rating
Yes
Gives WA even if the answer is correct.
This code always gives wrong answer on testcase 2. I get the correct answer on my IDE, but I saw that my answer(numbers) in the submission, are jumbled. Please look into this MikeMirzayanov
Even after successfully solving 1 question in div2 in my first contest why my rating is only 415.At the same time other people of my rank getting rating 1400+ even person whose ranking is greater then 10,000 they are also getting rating better then me ,please I want the answer of my question mine rank was 9,000 why is this happening. Please answer me
I participated in yesterday's contest (div 2 #662). My code was submitted successfully in the first attempt itself after passing the pretests. But now it is showing that I have solved 0 problems and on the final list my score is -1 whereas it was around 492 yesterday. I write my codes in C++ and had selected GNU C++ 17 as language while submitting. This was my first contest on Codeforces. Can anyone please help me understand the error?
Your code failed during system tests. It is not guaranteed that your solution is 100% correct if it passes the pretests.
this happened with me also in the last conetst.My solution was 100% correct because I tried submitting the same code and it was accepted.
Does Rating change in codeforces global round?
Yes.
Global rounds are rated for everyone
How to change my handle?
Codeforces allow handle change at the beginning of the year. So you have to wait until New Year 2021 to change your handle.
And it is not guaranteed, so maybe you won't be able to change it at all :)
i did not get updated my rating for 668(div2) rating can i know the reason behind this.
How do I set the name of university after creating the account without it?
just go to 1) your profile page 2) change settings 3) social subtab 4) add your organisaton (university)
There is no difference between Rating and Rating(all)
How can I delete my account? I have got a new email address now and dont want to use the old one anymore.
You can change email in your CF account by the way
Codeforces Round #680 Verdict is showing accepted but then why my rating drceases?
Rating is based on your rank in standing, not by accepted submission
I have just accidentally registered for a codeforces contest. How do I unregister?
Just don't give the contest. Your rating won't change unless you make a single submission.
Thanks!
MikeMirzayanov
I am sorry but i assumed that the handle change features was temporary magic feature. you wrote in the accouncement that we can request to rollback change.
i am requesting you to roll back my handle to previous one ' sirearsh '.
thankyou very much.
hey sometimes the compiler doesnt show the diagnose symbol to verify where have i went wrong? how can i find out the diagnose button?
If it doesn't show the button then it just doesn't have anything to show you.
104534400
Problem B: String LCM (Round 102)
Need help in understanding the time complexity of this Algorithm which I applied. Please check this submission and help me in analyzing its time complexity. It would matter to me a lot.
n=initial length of s
m=initial length of t
for each query, time complexity will be O(n*m)
because loop will run till n and m become lcm(n,m) which in worst case will be n*m
Thanks for replying!
But I still have doubt.
Lets consider this e.g. bbbbbbbbbbbbbbbbbbbb, n = 20 bbbbbbbbbbbbbbbbbbb, m = 19 LCM(s, t) = 20 * 19 = 380
For this example. the while loop runs 37 times. After 37 iterations, it got n = m = 380. So I am wondering how running time is n*m. As we have seen that the while loop is running only 37 times so what can be generalized?
You are not counting the time of concatenation of 2 strings.
In each iteration you are adding two strings
Concatinating 2 strings is not O(1) process
Why does the "Language" drop-down list show "Python 3.9.1" when it is in fact Python 3.8.1?
I have the same question. Tried to spot where the error arose, until I found that
math.lcm
is not supported.I just noticed that in my account whenever I go to organizations suddenly the username changes and starts showing someone else's name instead of mine the same thing happens when I click on the help link. Can someone explain why this is happening
how can i log off my account?
Since this is the main FAQ in the website, it should probably be updated to reflect that people in the [1900-2100] range will be rated when participating in Div.2 contests and also mention Div.3 contests.
Also, it might be a good idea to provide that information to participants when they are registering for a contest ("this contest will be rated for you, as you have a rating < x").
Hello MikeMirzayanov sir, I am facing issues with sending messages to users. I type the entire message and send it. But it shows blank as below image.
image link — https://imgur.com/abwIsr5
Can I know what's the issue ?
why i am not able to use bits/stdc++.h library file in my code
Well, MS C++ 2017 on Codeforces doesn't have that library.
If you want to use it you have to change your submission languages to GNU C++11 or GNU C++14 or GNU C++17 or GNU C++17(64)
Hello correct the rule 8. there is some incorrect information in there.
how can I import python3 modules, well I know how to import but when I submitted my code, it gave me a runtime error.
Excuse me, how to delete a team in Codeforces?
I want to delete a team which was created by myself, but after I deleted everyone else, I found that I couldn't delete myself, and a reminder appeared, "Team must have at least one active member."
How can I solve that?
@MikeMirzayanov Please update the number of divisions, it is 3 now no?
In yesterday's competition, I completed two questions and my rating did not rise, what is the reason?
Your submission were skipped by authore. because your solution matched with other's solution. (you and other user submited same source code) .This called cheating. That's why your rating didn't change.
I want to ask my friend, is there a way to change the name?
codeforces handle can be change once a year in first 10 days of january
Thank you
You are most welcome
How can I solve the problem of question as it is showing $ sign in all questions near all integers and characters It is much more difficult to read question...
Go to https://cdn-mathjax.codeforces.com/MathJax.js?config=TeX-AMS_HTML-full and click advanced -> proceed to site or similar depending on the browser.
The certificate expired last night, I'm sure it will soon be fixed anyway.
mrs MikeMirzayanov , I think if the website enable us to filter the problems depending on solved or unsolved will be more better as we can go to the unsolved problems and up solve it.
Mr. MikeMirzayanov, good evening! It's only my personal opinion, I think problem analysis is essential part of each contest, since sometimes you can't figure out a problem, cause you don't know some algorithm or technique that could possibly be very useful. I suggest to make filter on GYM section — does contest include problem analysis or not. It would be much better than just clicking at every contest and checking it manually.
My solution produce correct output on my compiler , i compile my same code that i have submitted during the contest after the contest is and it produces correct output. but according to codeforces compiler it produces wrong output
NOW WHAT I DO CODEFORCES PLEASE RECHECK MY SOLUTION AGAIN
wrong answer 4th numbers differ — expected: '1005355647', found: '1005355648'.
CONTEST --> Dytechlab Cup 2022.
PROBLEM --> B. Ela's Fitness and the Luxury Number.
INPUT TEST CASE NO. --> 11(L = 77921270569329490 , R = 377318254283917957) .
SOLUTION NO. --> 175009019
---------------------------------------------CODE-----------------------------------------------------
// AUTHOIR-->> YADAV_JI
include "bits/stdc++.h"
using namespace std;
define int long long
define pb push_back
define ppb pop_back
define pf push_front
define ppf pop_front
define all(x) (x).begin(),(x).end()
define uniq(v) (v).erase(unique(all(v)),(v).end())
define sz(x) (int)((x).size())
define fr first
define sc second
define pii pair<int,int>
define rep(i,a,b) for(int i=a;i<b;i++)
define mem1(a) memset(a,-1,sizeof(a))
define mem0(a) memset(a,0,sizeof(a))
define ppc __builtin_popcount
define ppcll __builtin_popcountll
template<typename T1,typename T2>istream& operator>>(istream& in,pair<T1,T2> &a){in>>a.fr>>a.sc;return in;} template<typename T1,typename T2>ostream& operator<<(ostream& out,pair<T1,T2> a){out<<a.fr<<" "<<a.sc;return out;} template<typename T,typename T1>T amax(T &a,T1 b){if(b>a)a=b;return a;} template<typename T,typename T1>T amin(T &a,T1 b){if(b<a)a=b;return a;}
const long long INF=1e18; const int32_t M=1e9+7; const int32_t MM=998244353;
const int N=1e5+5;
int n; std::vectorv; int a , b ,c ,d;
void SAKSHAM_YADAV(int test){ cin>>a>>b; int as = sqrt(a); int bs = sqrt(b); int ans = ((bs-as-1)*3); // ans = max(ans , 0ll); c = as; if((as*as) >= a)ans++; if((as*as + as) >= a)ans++; if((as*as + 2*as) >= a)ans++;
if((bs*bs) <= b)ans++; if((bs*bs + bs) <= b)ans++; if((bs*bs + 2*bs) <= b)ans++; std::cout << ans << std::endl; }
signed main(){ ios_base::sync_with_stdio(false); cin.tie(0);cout.tie(0); //freopen("input.txt", "r", stdin); //freopen("output.txt", "w", stdout); #ifdef SIEVE sieve(); #endif #ifdef NCR init(); #endif int t=1; cin>>t; rep(i,1,t+1) SAKSHAM_YADAV(i); return 0; }
---------------------------------------------CODE-----------------------------------------------------
use this
if I solved a problem correctly in the contest and later during contest, by mistake i submitted wrong code for that problem then, is question points are added or not to my points ??
how can i delete my account
what's "Can't send statement" when I want to open any problems
I submitted a problem's solution during contest time from two of my codeforces handles and the codeforces system skipped those solutions. I want my ratings change for those submissions. What should I do?
You are not allowed to participate from more than one account. That is one of the terms you agreed to when you registered for the round.
I want to change my handle It is allowed now till the tenth of January, but I originally logged in codeforces using my Gmail account I've never used a password, and they keep asking me to write my password for verification before I change the handle.
Hi,
I am a team leader with 10 members in my team.
Is it possible to create a contest for the members of my team with level of problems B and C in them.
It is important for the members to not be able to see the solutions during the test.
Please help here or if there is some sort of FAQ, it will also be helpful.
You can make a mash-up contest where you combine different problems from past codeforces rounds. If you want your problems to be truly original, in that case you can prepare them in polygon and add them to the contest.
How can change my username or Handle name??
My submission always gets stuck in a queue for too long, please provide me with a solution.
Can't unregister. Possible reason: you made at least one action in the contest what i should do ? When I go to the contest page, I go to friends and there is no "x" button to the right of my name. please fix it . link for contest : https://codeforces.net/group/746U2DXw2w/contest/510218
how much are the initial ratings distributed to each contest?And how much are the initial ratings in total? help me!
Hello i am beginner at cp and i am really confused as there is no cp culture in our school so what are the topics that i needed to start with and to reach specialist at cf. Please help me ?
A few days back, i had a rating of 1227 and before that i had a rating of 1191, and now i have a max rating of 1185, how is this possible. I have not given any contest after sunday?
I have small question, i have apply 1 course but when I submited 1 problem of this course, in my submission my problem just had 50 points. but when i open # of this problem i dont see any wrong test. moreover i dont see any word under my code. why like that? please!
Hello,I habe done about 100 of 800-900 rated questions by myself. Should i move to 1000 and above or should i try to do more of these 900.
hello How can i change my name on the site ?
Hi, I can see last 2 contest's rating updated and reduced then actually it was evaluated after contest. Is it usual to re evaluate contest rating later?
******What should I do, since I registered yesterday in Dev 2 and solved some problems, but I did not get any evaluation, whether positive or negative, and unlike all the people and my friends...it is a very strange thing.******
Subject: Request for Account Deletion
Dear Codeforces Support Team,
I would like to request the deletion of my Codeforces account. My username is NHRCSE.BD and My email is: [email protected]. Please let me know if you need any additional information from me to proceed with this request.
Thank you for your assistance.
Best regards, Nahid Hasan
Hey, I have a question What if people copy code from other or ask chatgpt for code and AC the proplems
Bring my Pinely Round 4 (Div. 1 + Div. 2) ratings back whose solutions are skipped and myy ratings were roll backed and reduced. I haven't cheated, i write my own code in sublime and try to build my logic sure i am newbie tryna push for pupil and specialist, but things would lead me down. I request Codeforces to bring my ratings back.
how to change handle?
My Codeforces account is blocked on my other computer, and I don't know whom to contact. I sent an email to a Codeforces address that sends news updates. Can someone help me?
Why my rating changes from 823-> to 0 suddenly
How can I create a group?
Hi everyone
I am trying to export the submissions and download the archive of them in a group contest but each time I try I get time out error 524.
Is there any solution to this problem?
To ask for clarification about ambiguities in contest statements or any specific rules, here are some steps you can try on platforms like Codeforces:
Check Contest Rules: Some contests have specific rules regarding clarification. Make sure you review the contest's instructions to see if there's an official way to ask questions. Use the Contest Clarification System: If the platform provides a built-in clarification request or chat option, use it to reach out to the contest administrators. Official Forum/Blog: Platforms like Codeforces often have blog posts or comment sections dedicated to each contest. Sometimes organizers or experienced users provide insights there. Profile Picture Guidelines: While platforms may suggest guidelines (e.g., a clear view of the user's face), the enforcement can vary. To avoid issues, follow the platform's recommendations closely. Search for Editorials and Resources: For editorials or guides, search using blog tags or categories specific to the platform, as many experienced users share resources through these posts. Following these guidelines can help you get the clarifications you need while staying within the platform’s norms and etiquette.
Thank you for the detailed outline! This is a great summary of how to handle clarification requests and find relevant information on competitive programming platforms like Codeforces.
If you have any specific questions or need further guidance on any of these steps, feel free to reach out. Good luck in your contests!
I can't see others submissions.where the codes was appearing in this section I just find N/A. How can I solve this issue. This is my new handle and I faced this problem in this handle..the previous handle is good,there is no problem
MikeMirzayanov i can't find my city
how can I change my handle? can anyone tell me?
Hello Codeforces Community,
I hope this message finds everyone well. I would like to request assistance in changing my handle." Unfortunately, I couldn't find an option to do so in the settings. I would greatly appreciate it if an admin could guide me.
If any administrators or moderators are available, please assist me with this request.
@ MikeMirzayanov, if it's within your scope, I kindly request your help.
Thank you for your time and support.
Best regards,
C_Shanto
You can only do it within the first week after registration or at the end of every year.
end means 1st january?
yeah, in first week of january.
Greetings Everyone! I am a begineer at codeforces. I am unable to see the solution if any problem. It just shows N/A followed by judgement protocol. Please tell me what to do? I am even unable to find the solutions online and don't even know how to look for the solution of a problem.
Please HELP !!!