Hi!
I've noticed an problem of lots of reports being put at random places and thus frequently unheard (if you ever tried to DM MikeMirzayanov, you most likely know what I'm talking about), so I take responsibility to declare this blog as a blog for collecting bug reports, proposals and other notes to mention considering the website codeforces.com Rules:
1) No off-topic. All unrelated comments will be downvoted, reported and deleted.
2) Please, share as much information related to your issue (if there is any) as you can. Simple "website doesn't work" can not be helped.
3) Other codeforces community rules apply here as well.
If you know about any unresolved issues, migrating them here will be appreciated. I'm not from CF web-design team so I have little power over the website itself so DMing me will most likely not help you (I don't prohibit it though).
Thanks and happy coding!
Proposal: When viewing problem set, add option to view only unsolved problems. Problems which we have already solved should not be visible in the list, if we have selected this option.
You can use this for now.
I think we will implement it, sounds easy to implement.
Google Chrome users can use CF enhancer(link) for now.
It has some really cool features beside that.
I got +130 in the last div 2 round without even being able to solve a single problem. Is this is a kind of bug? Sorry, I don't know much about codeforces rating system but getting positive delta without solving anything really bothers me. I think anyone must solve at least one problem to get positive rating changes regardless of the current rating.
The new rating system for newcomers will add extra rating for the first six contests. For the third contest you get 250 + delta. https://codeforces.net/blog/entry/77890
Will hacking/uphacking be expanded to
All of these would be nice, uphacking is a great feature to help promote understanding and strengthen tests, so it's unfortunate that it's not available everywhere.
Moreover, it seems that hacks in uphacking currently apply only to the hacked solution and solutions that are submitted after the hack has taken place. If there are several already submitted solutions that fail on the same test, you need to hack each of them manually. This can be automated on the hacker's side, but it would be easier if it was automated on the system's side somehow. Successful uphacks are pretty rare, so running all solutions to the problem on each successful uphack shouldn't be a big problem, computational-wise.
Sorry, it is not easy to implement it in this way. I don't think this is such a significant detail that it takes a lot of effort.
An uphacking can be applied only in case of a formal and complete validator and perfect solutions. For very old contests we can't guarantee it: problem writers and coordinators probably left Codeforces. Are 7 days really too short? I can extend it, but not for infinite: I like the idea of "freezing" a problem, it helps to move forward not spending much time on supporting old. For problems out of official Codeforces rounds we can't be sure about validators, so an uphacking can't be applied in general.
I want to hack ko_osaga 's 44864483 in this test case. I missed hacking phase ~1 hr and there was no uphacking phase back then. Please open uphacking phase of that contest for 5 mins. :P
50 1 2 1 9 1 20 2 3 2 4 2 8 2 16 3 6 4 5 4 7 4 10 5 12 5 30 6 13 7 11 7 24 7 25 10 36 11 15 11 18 11 19 11 37 11 49 12 14 12 21 12 32 12 34 13 28 14 33 15 17 15 22 15 26 16 23 19 38 20 45 22 35 24 50 25 27 25 29 25 31 26 39 27 43 28 46 33 44 37 41 38 40 38 42 38 47 38 48
The correct answer is - 44 48 34 47 With 7 common vertexes. Total Length 10+8.
But ko_osaga's answer is — 45 48 9 47 With 7 common vertexes. Total Length 9+8.
I got excited when you started uphacking only to find that I cant hack him. :(
Oh, wow, it's only 7 days?
Yes, that's very short in my opinion, since a big part of Codeforces is practicing (especially for Div1 participants who don't have as many rated rounds), and people frequently practice on problems from more than a week ago.
Even if it's difficult to add the test case, providing a simple feature to run the judge's solution & the submission on an input would be a convenient middle ground, instead of having to copy/paste and use Custom Invocation. (Basically, hacking without the same consequences of a successful hack.)
Please add "delete account" feature. Codechef and Atcoder already have that.
Yeah, there are definitely some people's accounts I'd like to delete. Not sure if such a feature could be abused though, maybe we could just allow deleting one's own account.
Ofcourse I meant deleting one's own account. Maybe for other accounts we can add "Report account" button.
I think we should be able to report comments/blogs/usernames/profile images for things that are plainly offensive and/or hate speech.
If we're worried about too many spammy false reporting, maybe we can only allow reporting by people who have done a certain number of contests (similar to the restrictions on Coach Mode and "Trust this user" etc).
It is in a background implementation right now.
Cool ! Hope to see it soon.
Please add: when using Mashup contest and my one problems from Polygon with IOI format — there is table with number of points achieved, but you can't see what is maximum. Also problem with IOI format — partial points is treated as OK, and you will get "Perfect score" verdict if you get OK on all tests. Each of this problems alone doesn't make a big deal but this mean that if you have IOI problem with partial points, it's possible to recive "Perfect score" when you get partial points on all the tests, and participant can't easily find what is maximum number of points — so he might not find out that his submition is wrong!
Here is example that happend on one of my training contests, but luckily we caught it early and told participant what went wrong! This is submition of simular code, but same problems arise — 313 is treated as perfect score because it got particial points on all tests, but 450 is the maximum!
I think it shows the maximum per problem. Am I wrong?
I think the problem is prepared in some strange way (like used obsolete
quitf(_pc(x))).I don't see maximum, maybe you're talking about some other place. On start is all blank:
... and as you submit you see how many points you got (but no maximum)...
For the problem with OK with partial points, here is checker I used (I used
quitp(_pc(number_of_points - 16)): LinkIs there better way to make partial points problem on Polygon? I couldn't find it, and it draw me crazy when I was preparing problem — my only problem with over 50 commits because of checker and problems with verdicts. Since then I didn't make any other partial score in one test, just making groups, that turned up really well...
We found simular problems during testing round but just fix it best we could (then we added line
if (number_of_points == 0) quitf(_WA, "all wrong")), and this problem with 313 points treated as "Perfect score" was found only during competition. TRequest: A way to view all contests and submissions of a team
(copied from this blog)
Good idea.
If you implement this, can you also implement all the virtual contests that the team has given? Because most teams have participated virtually in old team contests.
I think by "contests and submissions of a team" ZeyadKhattab means including even this.
I want to share a very old problem of codeforces not having a proper blog section. A proper blog section with options of viewing blogs of different topics(like dp, graphs, etc, just like in problemset section) and types(like study material, editorial, off-topic discussions, discussing problems, etc). This would be very helpful in learning good things and I have wondered for some past months that how come a site as big as codeforces have not done anything about this problem that has been asked so many times in the past. It would be really helpful to organize everything efficiently for all the users.
What about separating blogs from bugs and questions? Ideally I would enjoy having tabs like "Bug report", "Knowledge base", "Q&A" and regular blog posts. Having a searchable bug section would reduce the number of duplicates and probably add to the visibility of some issues. "Q&A" would host questions like "why is my solution not working on this test" that do not really have a blog nature. And useful tutorials could have a button "propose moving to the knowledge base". Seriously, there are plenty of good tutorials here, but you can only find them by luck or by hitting a blog post that contains links to them — and neither is good for beginners.
Allowing to view the people who have added you as a friend. You have 'X' friends, and you don't know who they are, sounds weird. Otherwise, it looks that the "Friends tab" is added purely for stalking purposes only.
I've noticed that there is no actual way to view all the blogs. If you want to see a old blog, you have to either search, or go into one's profile and look for the blog. I think it would be convenient if there were a blog menu that shows all the blogs, and can be sorted by recent, votes, etc. And maybe we can separate the announcements blogs from normal blogs.
Can there be a submissions vote feature,Just like for example ,We have 5 types of filters to sort the submissions by execution time,solution size,etc.If we can vote for submissions,we can sort those submissions based on number of votes and look at some good implementations.
Also,those solutions who look suspicious(if they have cheated) can be recognized easily by the negative votes.
These three issues relating to virtual participation have been mentioned many times (especially the second one), yet have not received any response.
CF-style scoreboard during virtual participation (currently, for some reason, during virtual participation, the scoreboard appears as ACM-style but turns back into CF-style after the contest ends).
Currently, all submissions during virtual contest are immediately judged on system tests. It would be better if they were judged on pretests only during the contest and judged on system tests when the contest ends.
Large numbers of cheaters reaching the top of unofficial standings, by copying others' code or writing their solutions before the virtual participation begins. At least one user has suggested removing virtual participants from the unofficial standings entirely (only allowing the virtual participant to see himself/herself in unofficial standings after virtual participation). See https://codeforces.net/blog/entry/78078 for more information.
I think virtual participation should be on unofficial standings. Without it, there's no way to compare myself with another guy that did not participated on live contest. I really don't care if cheaters are reaching the top of unofficial standings and i don't know why would i care about it.
If you use any extension in Firefox or Chrome so that the pages load in dark mode, like Dark Reader, the codeforces logo appears with white borders, because it is an image with a white background, this could be fixed by changing it to a PNG without a background I think it would be easy to do. Thanks for reading.
If I solve a problem like div2 D and then try to see the code of my submitted solution in corresponding div1 contest i.e. div1 B in this case then it is not visible.
Radewoosh's suggestion here: https://codeforces.net/blog/entry/78358, basically a CF Wiki where helpful blog posts are stored. If implementation of this is too hard I think a lot of the Gym's code could be reused, i.e. needing "coach mode" to edit, rating difficulty, etc. The only extra thing needed would be sorting by "tags", but in the meantime we could just make sure to have descriptive titles.
Option to show problem rating when I open an unsolved problem (even if I have unchecked
Show tags for solved problems).Tags are sometimes too helpful towards solving a problem, so it is important to disable tags. But if now want to see the problem's rating, I need to go and find it in Problemset,
Proposal: Please make the friends list sorted either by ratings or lexicographically. I wonder how the friends list is currently ordered!
According to what I observed the friends list is sorted as per the date on which the account was created .Those who created account earlier will come at the top and relatively newer accounts will come at the end.
If Mike sees this: probably, the fastest way of implementing this is making a default list Friends, or ability to add all your friends to a list. Lists already have the sorting functionality!
Zoom out big (tall) images in the comments? It is so annoying to scroll through all these huge memes in the comment section. Sometimes they take the entire height of my laptop screen :(
Proposal: After the contest ends, the number of people who solved a particular questions should be frozen. I recommend this because, when we later try to solve questions by randomly picking them up, we don't get a real idea how difficult the question was.
You can find this (less conveniently) by going to Standings and making sure it only shows official participation, then looking at the bottom row.
This blog may soon be out of recent and Top. How about pinning a link to this blog in top bar?
Proposal: Disable "diagonistical run after getting
Wrong answerandRuntime errorin C++" during virtual participationThat run would make a delay of receiving verdicts. We cannot see the testcases and diagonistic messages during virtual contests. Personally I would like to receive verdicts immediately, so it would be great to disable that almost useless run during virtuals.
(I'm not 100% sure if the delay of receiving
WAorREverdicts is caused by diagonistical run, so if there's an another reason, please point out that for me, really thanks)Also I wonder if there can be a choice to disable diagonistics during upsolving.
Please add problem tags for Gym problems and acm.sgu.ru problems.
I know there's already a lot of problems on Gym and acm.sgu.ru section, and it's impossible to add proper tags to all of them, but I think with the help of {high-rated people} $$$\cup\;$$${those who add contests to Gym}, eventually a good portion of these problems will have proper tags and this will be helpful for those who want to practice a certain topic. Anyway, this would be better than nothing.
On related topic: when preparing problems in Polygon, you can add tags — actually you will recive "warning" when commiting changes if you don't add tags: Here is example
So it is really possible that most of those problems already have tags on Polygon, MikeMirzayanov just needs to make a way to take tags from Polygon and put it in tranings/gym...
Wow, I was unaware of this. Thanks for the information.
Night Mode for Codeforces Website would be really awesome.
Enable 2FA. There are multiple incidents of hacking CF accounts.
Proposal: There can be a short optional survey after the contest ends, so that the problem setters get crucial feedback.
If I solve a problem in a mashup contest and later go to the original problem in problemset, I can see that it's marked green (solved), but I can't find my submissions. Also I can find no way to detect using API if an user has solved a problem (same problem can be present in multiple contests: Div1, Div2, private mashup).
There must also be a feature which allows us to see who made us friend. We are currently able to see our friend's list but we should also be able to see who made us friends.
Please add a option for see users who added me as a friend.
I think there is a problem with the search. I'm not sure it's only my machine or others too but I tried multiple browsers and all with the same problem. When I search any word it only give handles "Not blogs or anything else" many of the search I used was blogs I searched for in like a week ago without problem I even tried the examples and only worked with handles too!
I'd love separate toggles for "show difficulty" and "show tags" for unsolved problems. Sometimes I want to see the difficulty, but I don't want to see the tags.
Right now the only way I know how to do that is to go to Problemset and scroll forever.
65302/588817
Mobile version is not working on iPhone 8 Plus (and I guess similar sized phones) for a while now. Can we fix pls? :)
API request: add an optional parameter in
contest.standings():seconds_since_start, to retrieve the standings as it was atseconds_since_start.I think it's an easy thing because it's already implemented for virtual participants.
A proposal that has been ignored by MikeMirzayanov for a very long time now:
"A Form/mailbox or something by codeforces where people can report cases of definite cheating instead of having blogs everytime."
More context: https://codeforces.net/blog/entry/79271?#comment-649265
Middle button in time picker of virtual / mashup contests gives current time in UTC+3 irrespective of user's timezone. Please fix it.
I'm having a problem that codeforces doesn't work when I use my home WiFi but when I use cellular data it works just fine! I couldn't understand the reason to that but I was using the same WiFi to open it without problems 2-3 days ago. Anyone else facing the same issue?
Try changing your DNS.
Tried many ones same issue.