### Supermagzzz's blog

By Supermagzzz, history, 2 years ago, translation,

Hello, Codeforces!

We have planned this round as a Div. 4, but testing showed us, that problems are more suitable for Div. 3. Therefore, instead of the previously announced Div. 4 we will hold Div. 3 round.

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Hello! Codeforces Round #644 (Div. 3) will start at May/24/2020 16:35 (Moscow time). You will be offered 8 problems with expected difficulties to compose an interesting competition for participants with ratings up to 1600. However, all of you who wish to take part and have a rating 1600 or higher, can register for the round unofficially. The round will be hosted by rules of educational rounds (extended ACM-ICPC). Thus, during the round, solutions will be judged on preliminary tests, and after the round it will be a 12-hour phase of open hacks. I tried to make strong tests — just like you will be upset if many solutions fail after the contest is over.

You will be given 8 problems and 2 hours to solve them.

Note that the penalty for the wrong submission in this round (and the following Div. 3 rounds) is 10 minutes.

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behavior. To qualify as trusted participants of the third division, you must:

• take part in at least two rated rounds (and solve at least one problem in each of them),
• do not have a point of 1900 or higher in the rating.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you.

The problems for this round were invented by MikeMirzayanov and prepared by me and Stepavly

Thanks to MikeMirzayanov for platforms and coordination of our work. Thanks to antontrygubO_o, iankury, bfs.07, kocko, Ilya-bar, arsijo, pashka, Gassa, neal, vovuh for help in round preparation and testing the round.

Good luck!

</almost-copy-pasted-part>

UPD: Editorial is out

• +348

 » 2 years ago, # |   +19 Look forward to this round. Thanks for offering div 3 and 4!
 » 2 years ago, # |   +63
•  » » 2 years ago, # ^ |   +14 what does pawn mean in this context?
•  » » » 2 years ago, # ^ | ← Rev. 4 →   +84 People who getting faster round acception for being in relationship with Mike (By his opinion)
•  » » » » 2 years ago, # ^ |   +3 I think Mike doesn't like favoritism at all. This is all about practice.
•  » » » 2 years ago, # ^ |   -13 A pawn = puppet, marionette
•  » » » » 2 years ago, # ^ |   +1 Extremely rude.
•  » » 2 years ago, # ^ |   +227 Extremely rude.
•  » » » 2 years ago, # ^ |   +93
 » 2 years ago, # |   +56 Finally other author than vovuh for div3 contest
•  » » 2 years ago, # ^ |   +82 Last time vovuh wasn't one of the authors of a Div3 contest was 23 Div3 contests ago!!
•  » » » 2 years ago, # ^ |   +20 As the contest was prepared to be a D4 one, also everyone knows that vovuh doesn't prepare D4 contests(at least until now), so there is no vovuh as an author here.
•  » » » 2 years ago, # ^ |   0 I hope that you rock this round. All the best chota haath mota pait.
•  » » 2 years ago, # ^ |   +1 Because of the round previously announced as div. 4 :D
•  » » 2 years ago, # ^ |   -47
•  » » » 2 years ago, # ^ |   +2 This made me LOL, at least provide translation if you don't want downvotes lol
•  » » » » 2 years ago, # ^ |   +3 Hiruem chill h bro! Ye apne(indian) he hai jinhe samajh me sab aata h par phir bhi downvote karte h! Par apne ko ghanta pharak nhi padta bas thodi hasi thitholi ho jaye wahi bahut hai. I dont know why they cant take things as a joke.
•  » » » » » 2 years ago, # ^ |   +1 Yaar, tu to bahut chalu hay
 » 2 years ago, # |   0 Great!
 » 2 years ago, # |   -12 The time link always shows the Moscow time rather than the local time, please fix it
•  » » 2 years ago, # ^ |   -26 By the way thallium is not vegetable its an element . How you guys come up with such unique usernames??
 » 2 years ago, # | ← Rev. 2 →   +53 Div4 was an experiment. Keep maintaining the standard of Codeforces.
•  » » 2 years ago, # ^ |   -8 Yeah !! I too think the same
 » 2 years ago, # | ← Rev. 2 →   +21
 » 2 years ago, # | ← Rev. 2 →   -16 [deleted]
 » 2 years ago, # |   -125 Open at your own riskOk bOOmer
 » 2 years ago, # |   +26 Thanks for the div3 instead of div4 :)
 » 2 years ago, # |   0 This weekend is lit , as CF contest at 7pm IST and at 9.30 Codechef Cookoff . Noice
•  » » 2 years ago, # ^ |   +1 Yup. And then 2 codeforces round + lunchtime this week!!
 » 2 years ago, # |   -8 MikeMirzayanov Do you have any plan to run Division 4 regularly?
•  » » 2 years ago, # ^ |   0 That was supposed to be div4. So, i think yes, he do.
 » 2 years ago, # |   +35
 » 2 years ago, # | ← Rev. 2 →   -31 [Исключен]
•  » » 2 years ago, # ^ |   +35 did you even bother reading the first line of this blog...
•  » » 2 years ago, # ^ |   +19 You are accepted anyway, isn't that great!
 » 2 years ago, # | ← Rev. 2 →   -58 Исключен
 » 2 years ago, # |   0 Where is vovuh :|
•  » » 2 years ago, # ^ |   0 LOL, maybe it's the first div3 round which vovuh is not involved in.
•  » » » 2 years ago, # ^ |   +8 No its rare but not first time
 » 2 years ago, # |   +4 First time there will be 8 problems in Div3!!!
 » 2 years ago, # | ← Rev. 3 →   -13 Regular round for beginners should arrange more frequently...
 » 2 years ago, # |   -35 Is it rated since Division was changed from 4 to 3?
•  » » 2 years ago, # ^ |   0 yeah, it is rated
•  » » 2 years ago, # ^ |   +18 When it was div4 then it was rated for div4. Now it is div3 so it is rated for div3.
 » 2 years ago, # |   +4 Every time contest is organised after so many days, I get excited. It's other thing that I'm not able to solve more than 2 or 3 problems in contest.
 » 2 years ago, # |   -30 When a person sees C# ProgrammersC sharp Non programmersC hashtag
 » 2 years ago, # |   +5 I'm starting to miss vovuh already. :(
•  » » 2 years ago, # ^ |   0 And it has just been 9 days! .·´¯(>▂<)¯·.
 » 2 years ago, # |   +32 not div 4 Orz
 » 2 years ago, # |   +10 We missing out on a potential DIO meme here xD.
 » 2 years ago, # |   +3 Can anyone suggest best apps for writing code like codeblocks ( other than codeblock) for a windows user
•  » » 2 years ago, # ^ |   +2 Sublime Text, VS Code
•  » » 2 years ago, # ^ |   +3 You might enjoy using https://cpeditor.github.io/.
 » 2 years ago, # |   -16 Isn't it unfair that those who have ratings 1599 can participate in the contest and make their ratings 1800+ but those with rating 1601 can't change their ratings? You will be offered 8 problems with expected difficulties to compose an interesting competition for participants with ratings up to 1600 I'm sorry but I have found candidate masters who find questions from div 3 contests interesting.
•  » » 2 years ago, # ^ |   +24 So,what should be the boundary? If it is x, will not it be unfair to people with x+1 rating? :v
•  » » » 2 years ago, # ^ | ← Rev. 2 →   -6 One solution may be to cap the maximum achievable rating in div3 contests to 1600.
•  » » » » 2 years ago, # ^ |   0 It is a matter of fact that nearly all reds started at aprox 1580-1595 and then instantly jumped over 2000... where they happily lived ever after. Not.What is this nonsense about? You where below 1600 for like two years.
•  » » » » 2 years ago, # ^ |   0 What about people rated 1599 then? Not unfair to them?
•  » » 2 years ago, # ^ |   +25 Codeforces never let someone stay above his skill level. If someone has skill level for rating 1600 then if he somehow gets 1800 rating then he will come back to 1600 within two contest. If someone gets uneven rating increment in one contest then he will distribute it in next contest. He will not take the rating home and sell it in local market. Codeforces will never let him carry a rating which he doesn't deserve. So one uneven increment doesn't matter too much.
•  » » 2 years ago, # ^ | ← Rev. 2 →   +11 I find a master who thinks div3C is too hard for my level. Yes. He is myself.
•  » » » 2 years ago, # ^ |   0 wat, then how are you a master, sir? Even me, the holy noobie can sometimes do div3C
•  » » » » 2 years ago, # ^ |   0 Because I am not rated in div3, and I do well in div1(div1C is sometimes easier than div3C)
•  » » » » » 2 years ago, # ^ |   0 show me a div1C easier than a div3C, sir
•  » » » » » » 2 years ago, # ^ |   0 1338C - Perfect Triples is easier than 1216C - White Sheet
•  » » 2 years ago, # ^ |   0 This is a platform for practice so,if u are looking for placements wise even if u are expert company will hire you, if you are skilled. Happy coding!!. Take it in positive.
 » 2 years ago, # |   +16 _The problems for this round were invented MikeMirzayanov and prepared by me and Stepavly._ Please insert by before Sir MikeMirzayanov
 » 2 years ago, # |   0 Finally a contest after so many days. It will now be rated for me. Excited!
 » 2 years ago, # |   +117
 » 2 years ago, # | ← Rev. 3 →   +1
 » 2 years ago, # |   0 Will there be more Div 4 rounds??
•  » » 2 years ago, # ^ |   -10 Most probably, yes.
 » 2 years ago, # |   0 I miss vovuh. His problem explanation is great. I don't face difficulty understanding his words. Hope for the best for the new writer....
 » 2 years ago, # |   +1 8 problems!! This will be fun.
 » 2 years ago, # |   0 It was a div-4 contest when I registered. suddenly I found it div-3.
 » 2 years ago, # |   +30 And here we go "A non-vovuh Div3 round" after consecutive 23 Div3 rounds. Hats off to vovuh for this 23 round streak. Good luck to new authors.
 » 2 years ago, # |   +19 Maybe you could add one or two easier problems and delete the hardest problem, and then the contest could be div3 and div4, just like div1 and div2 in the past.
 » 2 years ago, # |   +6 Will the problems include sub-tasks?
•  » » 2 years ago, # ^ |   +8 No
•  » » » 2 years ago, # ^ | ← Rev. 2 →   0 your photo represents my sanity
 » 2 years ago, # |   0 What acctually means "Note that the penalty for the wrong submission in this round (and the following Div. 3 rounds) is 10 minutes"?? Can any one elaborate this line? please
•  » » 2 years ago, # ^ | ← Rev. 2 →   0 There occurs a penalty according to the time you submit a correct solution. The more time you take more penalty occurs. However, if you make a wrong submission then the extra 10 penalty will be imposed per wrong submission. Correct me if I am wrong.
•  » » » 2 years ago, # ^ |   0 Thanks
 » 2 years ago, # |   0 Can someone elaborate on what this line means:do not have a point of 1900 or higher in the rating.
•  » » 2 years ago, # ^ |   0 If someone has maximum rating 1900 or more then he will not be considered as trusted participant.
•  » » » 2 years ago, # ^ |   0 Can someone elaborate on what this line means: trusted participan
•  » » » » 2 years ago, # ^ | ← Rev. 2 →   +9 Sometimes some high ranked coder make fake account and participate in div3 rounds. So they get high rank on that contest. As a results, real participants can't know their real position in div3 contests. So, people who din't participate in at least two rated contests, then he will not be a trusted participant to stay in final standing. So, there will be no fake account on final standing and real participants can know their real position on standing. A high rank coder can loose rating on purpose to reach less than 1600 points and get a good rank officially in div3 rounds. So if a contestant has 1900 or more maximum rating then if loose rating towards less than 1600 them he will also be not considered as trusted participant and will remain out of final standing.
 » 2 years ago, # |   -16 Thanks 4 the time
 » 2 years ago, # |   0 I am sorry for the dumb question, but what does testing showed us, that problems are more suitable for Div. 3 mean? I mean, how does testing reveal suitability of problems for whatever division?
•  » » 2 years ago, # ^ |   0 same question
•  » » 2 years ago, # ^ |   0 When testing, they make a virtual contest environment and asks the testers to judge the problems. Based on their feedback authors decide.
•  » » » 2 years ago, # ^ |   0 By "judge the problems" you mean "assess problem difficulties"?
•  » » » » 2 years ago, # ^ |   0 Yes and also the clarity in the problem statements, testcases and everything.
 » 2 years ago, # |   +12 Good luck to all! Live solving the problems 15 mins after the contest finishes:https://youtu.be/gFepyRGn1vsOnly on Algopedia!
 » 2 years ago, # |   -6 can this contest be postponed for tomorrow? The codechef competition is also on the day. for last few days there was no competition on both sites and here we go. We have both on the same day and by half hour gap. The codechef schedule was announced before a long time.
•  » » 2 years ago, # ^ |   0 This round starts one hour earlier than the usual time, so that those two contests do not overlap. 25 minute break between rounds should be enough for you.
 » 2 years ago, # | ← Rev. 3 →   +6 To be honest,vovuh & MikeMirzayanov always makes nice problemset:)
•  » » 2 years ago, # ^ | ← Rev. 2 →   +3 .
 » 2 years ago, # |   0 odd time
 » 2 years ago, # |   +5 Eid Mubarak to all the contestants. Hope it will be a great contest for us before EID.
 » 2 years ago, # |   +27 It is div4, lol.
•  » » 2 years ago, # ^ | ← Rev. 2 →   +12 How to solve C?
•  » » 2 years ago, # ^ |   +12 It is div3+4.
 » 2 years ago, # | ← Rev. 2 →   -35 [deleted]
 » 2 years ago, # |   -6 It should not have been a div3.
•  » » 2 years ago, # ^ |   0 +1
•  » » 2 years ago, # ^ |   +6 Exactly
 » 2 years ago, # |   0 I didn't receive a reminder email
•  » » 2 years ago, # ^ |   0 Yep, it is our human mistake. We will double-check it next time.
•  » » » 23 months ago, # ^ |   0
 » 2 years ago, # |   -33 The comment removed because of Codeforces rules violation
•  » » 2 years ago, # ^ |   +1 WHAT?! This is the first time I see that codeforces removes comments
•  » » » 2 years ago, # ^ |   0 From time to time somebody talks about problems while contest.
 » 2 years ago, # |   -11 ConstructiveForces.`
 » 2 years ago, # |   +3
»
2 years ago, # |
+37

Quick editorial in Python. For more editorials visit this discord: http://interview.solutions

###### Question A
Question A - Tutorial
Question A - Code
###### Question B
Question B - Tutorial
Question B - Code
###### Question C
Question C - Tutorial
Question C - Code
###### Question D
Question D - Tutorial
Question D - Code
###### Question E
Question E - Tutorial
Question E - Code
###### Question F
Question F - Tutorial
Question F - Code
###### Question G
Question G - Tutorial
Question G - Code
###### Question H
Question H - Tutorial
Question H - Code
•  » » 2 years ago, # ^ |   +3 Men, thank you so much, you make this editorial faster than the speed of light
•  » » 2 years ago, # ^ |   0 Thanks a lot man!! Just looking at your editorial for a few minutes I was able to solve C & D in just a few minutes right after the contest & also realized how easy they were! I unnecessarily made my solutions complex, I should have thought & observed little more:(
 » 2 years ago, # | ← Rev. 2 →   -7 Problem G better version: https://vjudge.net/problem/LightOJ-1330Solution available on net.
•  » » 2 years ago, # ^ |   +26 But your G solution hacked .LOL
 » 2 years ago, # |   +10 1st time I solved 6 questions in a contest. Yipee!!
 » 2 years ago, # |   0 Can anyone help me with what peculiar case can be in Case#2 of problem F ? I kept getting WA on Case#2.
•  » » 2 years ago, # ^ |   0 try this 1 4 4 abcd aacd abbd abcc
 » 2 years ago, # |   +44
 » 2 years ago, # |   -8 G is same as lightOj 1330.
•  » » 2 years ago, # ^ |   +3 Not the same because you are not asked to output the lexicographically smallest, but is true that the solution of LightOj works for today's G
 » 2 years ago, # |   -9 is div3 hard? i couldn't able to solve single problem
•  » » 2 years ago, # ^ |   -6 If you call this hard, you don't know basic programming sorry.
 » 2 years ago, # |   0 It's the first time I was able to solve ABCDE. I think it's not DIV3, it's between DIV3 and DIV4 or 3.5
•  » » 2 years ago, # ^ |   0 Same goes for me. First time solved 5.
 » 2 years ago, # |   0 Why greedy isnt working for G?
•  » » 2 years ago, # ^ |   0 The greedy I came up with would give "NO" for 3 3 2 2
 » 2 years ago, # |   0 Can someone tell me why this got TLEd - https://codeforces.com/contest/1360/submission/81243429 and this got accepted - https://codeforces.com/contest/1360/submission/81245539Both are exactly the same code.
 » 2 years ago, # |   0 Seriously it's div3. Nope. I think it's the actual div4. Where you would have trivial A, B, C, D, E and not so trivial F, G and really hard H. G was super cool though. Felt like a fool after solving this.
 » 2 years ago, # | ← Rev. 2 →   -15 The input data of Problem H is 6MB at worst. Using cin will get TLE, using scanf will not get data because of strange '\n', using some other library also fail. A problem's difficulty should be how to solve it, not how to input it!!
•  » » 2 years ago, # ^ |   0 Well, actually, you can read non-whitespace character with scanf as such:scanf(" %c", &character);The space before the %c filters out all whitespace, so it becomes a non-issue. Alternatively, just use getchar/normal scanf and check whether it is a character between 'a' and 'z'.
•  » » 2 years ago, # ^ | ← Rev. 2 →   +4 I didn't believe there was an issue with problem G, since I solved it using cin, with the same expected complexity as given in the editorial.
•  » » 2 years ago, # ^ |   +26 Check the editorial. Our solution use cin and get AC.
 » 2 years ago, # |   +1 MikeMirzayanov Does increasing the number of questions of DIV4 makes the round DIV3? I hope thats not true for DIV2 round.
•  » » 2 years ago, # ^ |   0 I (personally) don't think so, since usually some contests that are harder or have more problems have their time extended, instead of increasing their division. Also, I (again, personally) believe problems G and H were more suitable to a div. 3 contest, rather than a div. 4 contest.Then again, I did not participate in the problem-setting nor testing of this round, so who knows ¯_(ツ)_/¯
 » 2 years ago, # |   +5 I actually spent more time debugging than reading and thinking combined..
 » 2 years ago, # |   0 Can anybody kindly show me a test case where this bruteforce(!) solution fails?
•  » » 2 years ago, # ^ |   0 3 2 bd db db
•  » » 2 years ago, # ^ |   0 12 3bbbbaathe answer could be "bab" , your solution prints -1.
•  » » 2 years ago, # ^ |   0 Thanks a lot to FL4G and A-m-z
 » 2 years ago, # |   -39 I hope this is the first and last div3 that you organised.
 » 2 years ago, # | ← Rev. 2 →   0 Can I see due to which test case my solution was hacked>?
 » 2 years ago, # |   0 Can Someone Explain how to do F?
 » 2 years ago, # |   -34 Guys head over to CodeChef Cookoff, it'll surely be more worth your time than those simple, time-wasting Div 3 problems https://www.codechef.com/COOK118B
 » 2 years ago, # |   +6 What is the best time complexity one can achieve for problem F ?
•  » » 2 years ago, # ^ |   +1 Definitely this is not the best, but let's analyze this:Take i-th string. Then for each position j, you try each of the N letters in the j-th column of input. There are N*N*M possible strings making this procedure. Then you need to check if that string works, in N*M complexity. Final complexity of this is O(N^3*M^2). I wonder if there's a O(N*M) solution
•  » » » 2 years ago, # ^ |   0 Thanks for sharing your approach :)
•  » » 2 years ago, # ^ |   0 O(N*M) is possible: https://codeforces.com/blog/entry/77846?#comment-628882
 » 2 years ago, # |   +4 For the first time in my life solved 5 problem. Thanks to the authors.
 » 2 years ago, # | ← Rev. 5 →   -14 I think this is not the standard Div. 3 Level. Make it Rated upto Div 4 only.
 » 2 years ago, # |   0 In F , I used the brute force concept and my run time complexity was O(n^3*m^2). How to solve it with larger constraints ?
•  » » 2 years ago, # ^ |   0 It can be solved in O(26*N*M^2) by trying to change every letter in the first string, to every possible value. Then you check if that string works.
 » 2 years ago, # |   0 This div3.5 contest was awesome
 » 2 years ago, # |   0 In problem f, why the code is getting RTE 81315889?can anyone please help me?
 » 2 years ago, # |   0 I think it was better to keep it div4. Div 3 E F problems are generaly much harder than all of these problems.
 » 2 years ago, # |   0 What is the Hack for problem D?
 » 2 years ago, # | ← Rev. 2 →   +14 MikeMirzayanovThis two people are copying codes i guess https://codeforces.com/contest/1360/submission/81303569 and https://codeforces.com/contest/1360/submission/81306780 other solutions of them are also similar. Their previous contest submission are also same. Sorry for bad english. Please look into such acts.Edit: I just saw that all their submissions are similar. They are taking plagiarism to next level.
•  » » 2 years ago, # ^ |   0 you forgot to mention that they are from the same university in Indian. And... they have the same rating graph =))
•  » » » 2 years ago, # ^ |   0 Yeah forgot to mention that thanks
 » 2 years ago, # |   0 Can anyone help me with what peculiar case can be in Case#2 of problem F ? I kept getting WA on Case#2 https://codeforces.com/contest/1360/submission/81313261
 » 2 years ago, # | ← Rev. 2 →   +9 I used bitmask dp to solve F in O(t*(1<
•  » » 2 years ago, # ^ |   0 I did the same but i forgot to mark my visited array because which my solution is running exponentially and guess what.. it still got accepted
•  » » 2 years ago, # ^ |   0 I think this will pass. In the recent educational contest my soln with 3e8 operation got accepted with 900ms.
•  » » » 2 years ago, # ^ |   +9 Actually I know this will get accepted....My problem is that it got accepted in 31ms which I didn't expect and it's 0(10^8). While O(10^9) shows tle in 5 sec....
 » 2 years ago, # |   0 how did you guys approach, your thought process to find out how to arrange all the one's
 » 2 years ago, # |   0 I used a network flow to solve G lol. Anyone else?
•  » » 2 years ago, # ^ |   +1 Can you please tell how to apply network flow here?
•  » » » 2 years ago, # ^ |   0 You can build $n$ nodes on the left and $m$ nodes on the right, representing the rows and columns. And link an edge from every row to every column, with capacity $1$. Then link an edge from the source to every row, with capacity $a$. Also an edge from every column to the sink, with capacity $b$.If the edge from the $i$-th row to the $j$-th column is full, put $1$ on $(i,j)$.
•  » » » » 2 years ago, # ^ |   0 Thanks for reply. But i have a doubt. Can you please tell — since the graph will not be unit-graph so complexity will be $O(V^2E)$ instead of $O(EV^{1/2})$ for unit-graph. Also edges will be of order $V^2$ So for $1000$ test-case time will be $O(1000*(50)^4)$ but still it's not giving TLE. why? Am i wrong in computing complexity? Please Help.
•  » » » » » 2 years ago, # ^ |   0 Oh it seems I got the complexity wrong. I didn't realise $E=n^2$ and thought it is $50^3$ per testcase. I don't know why it isn't giving TLE, maybe on such special graph the complexity is actually lower?
 » 2 years ago, # |   0 Can some cool guy explain the fact that when anyone ask "Is it rated",he must get many downvotes
•  » » 2 years ago, # ^ |   +3 Generally, it is written in the announcement if the contest is rated or not.
 » 2 years ago, # |   +1 Why do ppl still do that? :) Was that supposed to hide from hack?=> 81289430
•  » » 2 years ago, # ^ |   +2 maybe to not get caught by a plagiarism checker
 » 2 years ago, # |   +4 Pretests for Problem D were quite weak..... Lot of problem D solutions were hacked.... Felt demotivated after hacked question, as it affects rankings a lot.....
•  » » 2 years ago, # ^ |   +1 I'm so sorry I was upvoting your comment but it got downvoted. What did I do I'm so sorry!
•  » » » 2 years ago, # ^ |   0 Hey Divya... Its OK....
 » 2 years ago, # |   0 What is Test Case #57 for test set 2 of problem F ??
•  » » 2 years ago, # ^ |   0 Never mind, i found my mistake
 » 2 years ago, # |   0 Has the system testing finished? If so when will the ratings change?
•  » » 2 years ago, # ^ |   0 Wait till evening
•  » » » 2 years ago, # ^ |   0 What why?
•  » » » » 2 years ago, # ^ |   0 It takes a few hours before ratings are updated
 » 2 years ago, # |   0 Why am i still unrated even after participating in the contest and given solution 3 problems?
•  » » 2 years ago, # ^ |   0 Cuz they haven't given out the rating updates yet. Look system testing started. It'll happen soon enough I guess.
•  » » » 2 years ago, # ^ |   +5 Ok I am new to this site . Thanks for helping out
 » 2 years ago, # |   +3 If you had felt that the problems are bit difficult for DIV4 you should have put some easy problems in place of those hard problems and make the contest as DIV4. I think the problems are easy for DIV3.
 » 2 years ago, # |   +1 Will i be awarded points for successful hacks in this contest... If Yes then how will it be adjusted to the final rankings
•  » » 2 years ago, # ^ |   +1 No, you won't be awarded any extra points for a solution hack. It's just that it will affect others' solutions after the system test, and your rank might move up the table (because of others moving down).Hacking doesn't yield extra points in Educational and Div 3 rounds (both follow extended ICPC rules for scoring).
•  » » » 2 years ago, # ^ |   +1 Thank You for Information.....
 » 2 years ago, # |   0 A very fast system test today after quite some time. Even after the number of participants.
•  » » 2 years ago, # ^ |   +1 Yes hardly took 40 mins to finish
 » 2 years ago, # |   0 My first screencast. Would take suggestions to improve.
 » 2 years ago, # |   0 when will the rating be updated?
 » 2 years ago, # |   +5 I would like to appreciate MikeMirzayanov and his whole team for an amazing round. There was no queue during the contest and it ran very smoothly. So it was great work by codeforces team. I hope future rounds are going to be the same one as this.
 » 2 years ago, # | ← Rev. 3 →   0 Hey..i am a school student and i just got introduced to codeforces. i took the above mentioned challenge and managed to solve 2 problems, post that my laptop got shut unfortunately. However, both the submitted questions were accepted in the first test as well as post the open hack and system test session. But i haven't got any updates regarding my performance or ratings. I am new to this. Please tell me what am i supposed to do?
 » 2 years ago, # | ← Rev. 2 →   +4 Dang its been almost 3 hours since the system testing finished, how come no rating update yet?
 » 2 years ago, # |   +2 why is my rating not changing even after the final standings of the contest are out
•  » » 2 years ago, # ^ |   0 I have the same question.
 » 2 years ago, # | ← Rev. 2 →   0 for F question. I haven't copied the code and it is entirely different anyways...please resolve the issue asap. I think this may be caused due to the input reader method. Not the logic of the question. manish_98 solution: https://codeforces.com/contest/1360/submission/81281906 my solution: https://codeforces.com/contest/1360/submission/81299107update : issue resolved by Mike :)
 » 2 years ago, # |   0 rain-maker and return_47 are both my accounts with different gmail id's.I made them to treat one as main and one as practise account hope you understand therefore it's not the case of cheating
•  » » 2 years ago, # ^ |   0 I can verify
•  » » » 2 years ago, # ^ |   0 @Cf decreased my rating but my solution got accepted from one account
 » 2 years ago, # |   0 It's not cheating both are same
 » 2 years ago, # |   0 Similar message appeared to me as well of copying and I have used unfair means to copy from aman_shah username. Sincere apologies and you can take action against me.
 » 2 years ago, # |   +1 Funny that my first time I solved 5 problems, I decreased in rate :P
 » 2 years ago, # |   0 Can someone explain how this user went to CM without solving even a single problem?
•  » » 2 years ago, # ^ | ← Rev. 2 →   0 I think it's because of changes made for the new rating distribution, and I think they messed up somewhere.According to the post, that user should get -100, but since the first contest displays a rating of 500 + (rating that the user should differ by in the contest), the user was able to get +400 rating.
 » 2 years ago, # |   +13 Wow, is this even real?
•  » » 2 years ago, # ^ |   +1 bug?
•  » » » 2 years ago, # ^ |   +2 Probably. The latest contest's rating changes are rolled back right now. I hope mine will change to make me an expert :P
 » 2 years ago, # |   0 Why my consts list did not add the const but my rating still changed?
 » 2 years ago, # |   +4 What the hell! New Ids becoming Master/International Masters with +800 Rating.
 » 2 years ago, # |   +3 I see many success stories on the way titled "How I became an International master in 2 hours "
 » 2 years ago, # | ← Rev. 2 →   0 I think some mess has taken place while rating changes... In all the contests the CF rating predictor- CF-Predictor-Herokuapp shows the correct rating changes and every time I have seen the rating predictions here are accurate but in the last div.4 and this div.3, I have seen that the actual ratings are near about -10 than shown in the predictor. In div.2 contests, it works correctly. I think the predictor has some bug while calculating rating changes. In fact in the last div.4 and this div.3, I see that the actual ratings of mine differ by -10 as compared to those shown in the predictor. See the following rating predictions as shown by CF Predictor(the delta column) and the actual rating changes can be found in the above comments.:
 » 2 years ago, # |   0 I have observed that problems in CF Round #644 (Div 3) were quite easy. Except the last, all problems had 2000+ successful submissions during the contest. Due to this, the rating of participant in 1400-1600 exploded. Adding more to this, new accounts became masters just by solving 2 problems last night. LOLzz.This might be due to new rating system. However, this completely destroys the motive of the new rating mechanism, that was to reduce creation of new accounts.I propose two points after seeing what happened: Withdraw the new rating system. Make prev. round unrated for participants who were in 1400-1600 before the contest. As the problems were indeed suitable for Div 4 contests only. Comment if you agree/disagree with my proposal.
•  » » 2 years ago, # ^ |   0 agree
•  » » 2 years ago, # ^ |   0 completetly agree
•  » » 2 years ago, # ^ |   0 Totally 100% agree I believe people with ratings between 1200-1400 suffered the most, because even if they performed decently according to what should have been a div4, they got large down plunges in ratings.
•  » » 2 years ago, # ^ |   +2 First one is more appropriate
•  » » 2 years ago, # ^ |   0 Disagree. When the problem setters already claimed that this set of problems was more suitable for Div 3, then why debate on it? They have much more experience (along with better coding skills) than us. And, don't forget that among those 2000+ successful submissions, there are also submissions made by unofficial contestants.
•  » » » 2 years ago, # ^ |   0 +1
 » 2 years ago, # |   +3 rating changes are rolled back already
 » 2 years ago, # | ← Rev. 2 →   +1 I become expert today for the first time..That's a great feeling .
 » 2 years ago, # |   0 From my profile page, Rank displayed is 6204. Whereas from the contest's standing page, it's 8146. Is this a bug or is there some reason behind it?
•  » » 2 years ago, # ^ |   0 The rank which you are seeing on the contest standing page also includes the particants with rating above 1600(i.e the ones not eligible for Div3)
 » 2 years ago, # |   0 Can u explain me Spy Strings
 » 2 years ago, # |   0 After Participating, I felt it was more suitable for Div 4 rounds. Although its not a big deal!!
 » 23 months ago, # |   0 There is a problem in test case 2 (20) in problem 2.
•  » » 23 months ago, # ^ |   0 Let me guess: You solved it, but the grader says "wrong answer".
•  » » » 23 months ago, # ^ | ← Rev. 2 →   +3 Yes. What is the problem here? I solved it manually also, it shouldn't be answer it shows.
•  » » » » 23 months ago, # ^ |   0 If you link your submission propably somebody can tell you.
•  » » 19 months ago, # ^ |   0 No not a problem in the testcase
 » 19 months ago, # |   -10 In the third question's sample input and output.I think the last sub-test case is wrong in the output as6 1 12 3 10 5 8In this task 12 and 10 form a pair whose remainder is equal i.e., 12 / 2 = 0 and 10 / 2 also = 0So the output should be YES as the conditions meet but the output is NO in the sample outputCan someone clarify my doubt