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Denisson's blog

By Denisson, history, 2 years ago, translation, ,

Hello Codeforces!

Round will start on Thursday, 3 November in 19:05 MSK.

Tasks are prepared by Anton Garder (ayoyia) and me, Shpakovskiy Denis (Denisson). Thanks to gainullin.ildar, glebodin, neckbosov, cdkrot, Arpa, Starcall for testing problems, gritukan for coordination and translation, MikeMirzayanov for Codeforces and Polygon platforms.

You will have six problems to solve in 2.5 hours.

Hope you will enjoy problems. Good luck to all!

Scoring: 500—1000—1500—2000—2500—3000

We want to apologise for mistakes in problem statements that led to round being unrated

Editorial.

• -479

 » 2 years ago, # |   -120 RATED ???
•  » » 2 years ago, # ^ |   +82
•  » » » 2 years ago, # ^ |   -28 hahahahaha
•  » » » 2 years ago, # ^ |   +53 and now it's unrated :D
•  » » » » 2 years ago, # ^ | ← Rev. 2 →   -23 was it announced?! i hope not, I wasted a lot of time in getting my C accepted :(EDIT: Yes it really is unrated, RIP my 50 minutes :(
•  » » » » » 2 years ago, # ^ |   +38 You did not waste it, rated or unrated you solved the problem and its always worth the time
•  » » » » 2 years ago, # ^ |   0 And apparently you and otakucoder both were in my room. Well, I guess you commented here because you were in my room, right? Or not? I don't know anymore...sighs...
•  » » » » » 2 years ago, # ^ |   +4 Hahaha its destiny bro
•  » » » » 2 years ago, # ^ | ← Rev. 2 →   -15 Unrated CF R contest should be somehow become RATED with different Rating Algo
•  » » 2 years ago, # ^ | ← Rev. 3 →   -15 isnt it time to leave old methods of getting downvotes ??:(( just by looking at your contributions any can understand your story ;
•  » » » 2 years ago, # ^ |   +12 have you ever seen grey guys with good contribution?
•  » » » » 2 years ago, # ^ |   -22
•  » » » » » 2 years ago, # ^ |   +24 Dude he ain't grey.
•  » » 2 years ago, # ^ |   +28
•  » » 2 years ago, # ^ |   +8 It was
•  » » » 2 years ago, # ^ |   +8 It was really bad joke, because it's true
•  » » » 2 years ago, # ^ | ← Rev. 2 →   -13 .
•  » » 2 years ago, # ^ |   -10 NO
•  » » 2 years ago, # ^ |   +15 No, it is not rated.
•  » » 2 years ago, # ^ |   +20 Aah, I still can't believe this round had 6 testers. I mean, how could they even comprehend and test such problems? Hats off mate!
•  » » 2 years ago, # ^ |   0 Apparently NO it is not
•  » » 2 years ago, # ^ |   0 Well, it wasn't rated :v
 » 2 years ago, # |   0 3rd october??? :P
•  » » 2 years ago, # ^ |   -20 yeha
•  » » 2 years ago, # ^ |   -10 It obviously means 3rd November.Denisson
 » 2 years ago, # |   -31 hi guys im trying to have the worst contribution possible on this sit Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?Is It RaTeD?
•  » » 2 years ago, # ^ |   0
•  » » 2 years ago, # ^ |   -36 Now no comments :p
•  » » 2 years ago, # ^ |   +10 not for me, bro
•  » » » 2 years ago, # ^ |   +1 not for all bro.
•  » » 2 years ago, # ^ |   +27 guys you just got me from contribution -10 to -9 please downvote don't upvote im trying to have the trashiest contribution!!!
•  » » » 2 years ago, # ^ |   -6 I think he deliberately said that he wanted to be downvoted in order to wangle our upvotes :)
•  » » » » 2 years ago, # ^ |   +4 no i really mean to be downvoted
•  » » 2 years ago, # ^ |   +10 well you have more contribution than the problemsetter...
 » 2 years ago, # | ← Rev. 2 →   -39 .
 » 2 years ago, # | ← Rev. 2 →   -11 I can't understand why even a expert/candidate master level programmer in codeforces comment "is it rated?"..I think they may be go to out of the human world during their comment time!
 » 2 years ago, # |   -23 Who is ready to contest?
 » 2 years ago, # | ← Rev. 2 →   -29 Why always me?
•  » » 2 years ago, # ^ |   -32
•  » » » 2 years ago, # ^ | ← Rev. 2 →   -15 DELETED
 » 2 years ago, # |   +1 Thanks a lot to Denisson for providing us with this kind of enjoyable moments. And good luck to All who like coding without worrying about if IT IS RATED or NOT. :)
 » 2 years ago, # |   -6 UNRATED ?
 » 2 years ago, # |   +40 In april 2016 something life-changing happened with Denisson =)
•  » » 2 years ago, # ^ |   +61 He stopped asking if contest is RATED ...
•  » » 2 years ago, # ^ | ← Rev. 3 →   0 There are too many these kind of fluctuations in YOURSELF's coding career on codeforces. IS the secret of that RED BULL or ENERGY drink ?:)
•  » » 2 years ago, # ^ |   +4 He drank Red Bull that night.
•  » » 2 years ago, # ^ |   0 Yeaah i noticed that must have been so cool
 » 2 years ago, # |   +8 Super excited to give this contest. Codeforces, you made my day! Thank you so much!
 » 2 years ago, # |   +2 Would be great if this contest features the number "4", celebrating the "444th" Div2 round.
 » 2 years ago, # |   +5 Palindromic Contest!444
 » 2 years ago, # | ← Rev. 2 →   -19 Why people are downvoting me i can't understand:(
•  » » 2 years ago, # ^ |   -12
•  » » » 2 years ago, # ^ |   +2 what are u saying
•  » » 2 years ago, # ^ |   0 You are allowed not to mind about 10-100 downvotes: because 10 downvotes in a single comment is not so important in most people’s life.
 » 2 years ago, # | ← Rev. 2 →   0 Unrated!
 » 2 years ago, # |   +2 In the C,the pos.2 & pos.5 color?
 » 2 years ago, # |   +138 Am I the only one that doesnt like the contest ? glad this is unrated for me so i dont have to solve C :/
•  » » 2 years ago, # ^ |   0 Unrated for everyone it seems :P
•  » » 2 years ago, # ^ |   0 Problem c was really bad. I really got frustated and closed my laptop and went to sleep.
 » 2 years ago, # |   0 Is there some problem with sample input 1 and its given output in C? I think there is.
 » 2 years ago, # |   0 Does problem C promises that color 1's opposite is color 4 and so on as sample input?
•  » » 2 years ago, # ^ |   +3 you know there is a "ask a question" part in the contest right ?
 » 2 years ago, # |   +35 1 ) Problem Statements are not clear 2 ) Too many pop ups in between contests 3 ) Codeforces is not responding sometimes. 4 ) For problem C ,Image was not correct earlierI thinks it is better to unrate this contest rather than unfair.
•  » » 2 years ago, # ^ | ← Rev. 2 →   +3 OH, I was wondering why my code did not work. Because I wrote it completely based on picture. That is annoying -_- EDIT: Picture is not wrong, but without clarification I did something else/not what the problem wanted.
 » 2 years ago, # |   +27 What the hell is happening? A lot of problem with problem statement. "You can remove no digits (that is, leave it as is)." This cost me 5 WA. Important information of problem C is given after 1:30 hr "You should do exactly one rotation of cube" "There was an issue with picture in notes for problem C, now it's fixed" . Is it a joke?
•  » » 2 years ago, # ^ |   0 If we can remove no digit then how is 100010001 divisible by 64 ?
•  » » » 2 years ago, # ^ | ← Rev. 3 →   +1 1000000 In this we can remove no digit
 » 2 years ago, # |   +44 I wish I wouldn't have participated in this :/
 » 2 years ago, # |   -6 I don't know what is Rubik's cube, I didn;t use it before. Am I suppose to know such things also before a contest ?What is a rotation ? And how did the author make a mistake with the image ? That is the only hope for peoiple like me who dont know this stupid game.
•  » » 2 years ago, # ^ |   0 The game is quite popular. It's also not stupid.
•  » » » 2 years ago, # ^ |   -29 But if someone isin't aware of it, should they fuck themselves and loose rating ? Don't u think if this happens with u(for some other game), it is very unfair ?
•  » » » » 2 years ago, # ^ |   +13 I go to wikipedia and read about the game. It's not really the author's job to make sure we all know every game on earth. Isn't it kinda expected that we'll know tic tac toe?
•  » » 2 years ago, # ^ |   +27 What if you were asked a question on some algorithm which you don't know but is very famous. Do you still blame the author that you don't know and so bad question?? It seems yes.
•  » » » 2 years ago, # ^ |   0 Well, your point is a bit orthogonal, as knowing algorithms is directly related to CP. However, I think the author isn't wrong to include a problem on something as well known as rubiks cube. In the past we had problems about Matryoshka dolls too.
 » 2 years ago, # |   +9 Very bad contest. Server HTTP 500 many times. The weird Rubik never played before.
 » 2 years ago, # |   0 An occupy contest :|
 » 2 years ago, # | ← Rev. 2 →   +38 In Problem C , Defination of a rotation could be given by author , we are not CHAMPIONS in rubrik game like you Denisson
 » 2 years ago, # | ← Rev. 2 →   -18 Great contest for me first time solved 2 questions:)
•  » » 2 years ago, # ^ |   +2 I solved three problems and now it became unrated :(
 » 2 years ago, # |   -6 What the fuck????
 » 2 years ago, # |   +35 Good contest (no)
 » 2 years ago, # |   0 Unlucky
 » 2 years ago, # |   -8 UNRATED?!?!
 » 2 years ago, # |   +18 Oh fuck..I spent almost 1 and half hour on problem D figuring out how the hell can one solve it in given time limit.
 » 2 years ago, # |   +24 I think more clarity should be given in implementation based problems like C.
 » 2 years ago, # |   +59 My code for C was more than 200 lines long and now the contest is unrated...ARE YOU FUCKING KIDDING ME ?!?!??!?!
•  » » 2 years ago, # ^ |   0 Are you sure, that your code will pass system tests ? =)
•  » » » 2 years ago, # ^ |   0 You and haleyk100198 are probably right but it still hurts too much.I should be thankful I was gonna lose rating but now I'm good.:)
•  » » » » 2 years ago, # ^ |   0 I think you still need to submit your code =)I will look into your implementation after contest ends. It is interesting to compare your solution with mine =)
•  » » » » » 2 years ago, # ^ |   0 My solution isn't done yet but I can send you what I wrote it isn't full but the idea is very clear.
•  » » 2 years ago, # ^ |   +30 Well, if you think positively, long implementation codes usually get randomly screwed by test cases 100+ ...
 » 2 years ago, # |   +17 It's been a long time since I've been in the top 100, and now, unrated... :(( :((
 » 2 years ago, # |   +37 This round is SOOO unprepared. Shame on you.
 » 2 years ago, # |   +13 Thanks for the wonderful contest without ANY mistakes and troubles.
 » 2 years ago, # |   +18 When you have an amazing CF once a year, and rounds get unrated once a year :D
 » 2 years ago, # | ← Rev. 3 →   +49 Cracking 15 solutions, solving A+B+C, going top2Round would be unrated TRIGGEREDPS: Sorry room 52 :D
 » 2 years ago, # |   +13 Great. Skipped class to improve rating! :(
 » 2 years ago, # |   +5 For the first time in top300: unrated. SAD!
•  » » 2 years ago, # ^ |   +19 But it is your first contest, suspicious >.<
 » 2 years ago, # |   +11 Very bad contest. Long duration contest like this one should have dp and graph problems instead rather than implementation major.
•  » » 2 years ago, # ^ |   +2 Umm what? There's no such rule like that. I agree that not all problems should be annoying implementation problems, but doesn't mean long contests SHOULD feature graph and dp problems.
 » 2 years ago, # |   +10 many Announcement for A and C :| unrate for D :|||||
 » 2 years ago, # |   +11 Dear Denisson and ayoyia, it was my best contest ever, you know??? I am...heartbroken...
 » 2 years ago, # |   +28 Salute to the ones who wrote C XD
•  » » 2 years ago, # ^ |   -16 I don't see what's the problem with C. Why are some guys unhappy with C?
•  » » » 2 years ago, # ^ |   -8 because it doesn't have any algorithms. Just rotate a 2x2 cube. It isn't a problem for codeforces.
•  » » » » 2 years ago, # ^ |   +12 I personally feel otherwise. You can see some very fast submission times, which means it's a problem to think about how elegant and short our approach can be. Isn't that useful in CP?
•  » » » » » 2 years ago, # ^ |   0 I thought, we are solving olympiad-like problems. They usually include graphs, DP, data structures, even geometry. I can't even give a type to problem C.
•  » » » » » 2 years ago, # ^ |   0 But I don't even know how rotations occur in rubik's cube. Isin't the author responsible for explaining that ?I guess this game is abstract and should at least be explained to be included in a contest.I can prepare some really hardcore physics problems , that would take u 10+ hours to understand.Should this start happening >?
 » 2 years ago, # |   +7 Shitty problems...
 » 2 years ago, # |   +27 Worst C ever. Thank god its unrated.
 » 2 years ago, # |   +85 When you don't want to spend time thinking what happens after rotating a cube and instead spend more time doing this: -_-
•  » » 2 years ago, # ^ |   +38 Don't send solution during contest, even if it's unrated.
•  » » » 2 years ago, # ^ |   0 Well, this isn't an solution.
•  » » » 2 years ago, # ^ | ← Rev. 2 →   +31 Do you really think someone will copy this long text without error after all this inconvenience?
•  » » » 2 years ago, # ^ | ← Rev. 2 →   +11 Aha, sorry for that..... Totally forgot the contest is still ongoing after that unrated announcementThough I doubt there is another dull-headed guy like me who is gonna try writing these whole thing :v
•  » » » » 2 years ago, # ^ |   +1 No need for 12 only 6 cases. Your 6 are duplicate :)
•  » » » » » 2 years ago, # ^ |   0 True.... Didn't realize some rotation produces equivalent results.
•  » » 2 years ago, # ^ |   0 Really?!
•  » » 2 years ago, # ^ |   0 what the hell is this
•  » » 2 years ago, # ^ |   0 It's only have 6 cases with 3 different ways to rotation and 2 direction each way...
•  » » 2 years ago, # ^ |   +18 It could be simpler..
•  » » » 2 years ago, # ^ |   0 I know it could be simpler.... actually my approach was "this couldn't be any harder/dumber"
 » 2 years ago, # |   +17 May i ask whether the writer or the testers or anyone involved with the preparation of the contest had even read the problem statements? even the Announcement had grammatical errors!
 » 2 years ago, # |   0 rip
 » 2 years ago, # |   +5 Many problems to be pointed out there, including unclear statements (at least in English, I'm not sure about the original ones) or extremely scarce range of pretests (I even received "Pretest passed" for problem B even though I misunderstood the problem statement, and well, of course, it got hacked later xD) Hope your next contest would be better.
 » 2 years ago, # |   +15 I'm in top 100, but I have to say that this round should be unrated even if statement of D was correct...
 » 2 years ago, # |   +14 Contest held after so many days and then it becomes unrated. Not expected.
 » 2 years ago, # |   +182
 » 2 years ago, # |   +1 It is my best rank,but unrated now . T_T. go to sleep now... (midnight)
•  » » 2 years ago, # ^ |   0 GN Sakamoto kun
•  » » 2 years ago, # ^ |   0 darthmelonder does it relate you bro :|
•  » » » 2 years ago, # ^ |   0 It seems usual now, Happens every time i get good rank :P
 » 2 years ago, # |   +4 i should have become an expert :(
 » 2 years ago, # |   +42 I'm getting so sick of CF rounds. It seems every time I participate something goes wrong, either during contest or during systest. Every other round is unrated, problems are mostly unimaginative and I wonder why I should devote 2h of my day for such contests. Today's round was another hack round, no knowledge required to be in top20 (just a bad enough room). A's most obvious 'corner case' should've been in the pretests. All C solutions I saw while hacking were hideous, and if the solution was "check all possibilities", it's really bad. This rounds issue wasn't D, it was the whole round. (this comment doesn't concern E and F since I haven't tried them, but just looking at the number of ACs, it seems too hard for a div2 round).Now excuse me, I'm off to solve some CSAcademy problems.
•  » » 2 years ago, # ^ |   -20 If you're getting sick, better not compete here anymore, you absolutely don't have to. If you do, you'd better accept that mistakes can be made and respect the effort of the authors. Or don't listen to my advice and be sour... |-)
•  » » » 2 years ago, # ^ |   +9 This is not about this particular contest or author (even thought in my earlier frustration it might have sounded differently), it's about how often it is, and that I can rarely just compete uninterrupted on this platform. There is a saying "We critique the things we love, so they could be even better", I love CF and its community and I want it to do good, I was just voicing my frustrations.
 » 2 years ago, # |   +313 CodeForces judge today:
•  » » 2 years ago, # ^ |   +25 best usage of a gif I have seen in my life so far.
 » 2 years ago, # |   +1
 » 2 years ago, # |   -41 The comment is hidden because of too negative feedback, click here to view it
 » 2 years ago, # |   +18 It's time to meme when the rating increase is a dream
 » 2 years ago, # |   +1 The comment is hidden because of too negative feedback, click here to view it
 » 2 years ago, # | ← Rev. 6 →   +13 There were many errors in the problem statement (Specially in problem C). But many contestants solve this problems before the clarification. The must have some supernatural power or they are superman.
•  » » 2 years ago, # ^ |   +1 There are 3 possibilities: 1. They solved these problems based on their own knowledge (about rubiks, cubes, or something similar) 2. They took a guess. Like in Problem C, we could guess the order of the color no. based on the diagrams. 3. If things got too dicey, you can ask the jury. Remember that feature, you'll need it, perhaps even in a real contest.
•  » » » 2 years ago, # ^ |   0 Yes we could guess the order of the color number. But how can we guess "You should do exactly one rotation of cube" ?
•  » » » » 2 years ago, # ^ |   0 I had to read twice to see whether zero rotations would be allowed, but was able to conclude from the problem statement that it was not. The announcement was not necessary. And in my opinion proper reading is part of the challenge.
•  » » » » » 2 years ago, # ^ |   0 Yes I agree with you that proper reading is part of the challenge. But how can you understand it is valid to delete no digit form this statement "Her problem is following: for given string, consisting of only 0 and 1, tell if it's possible to remove some digits in such a way, that remaining number is a representation of some positive integer, divisible by 64, in the binary numerical system." ? Is (some==none) gives you a 1 ?
•  » » » » » » 2 years ago, # ^ |   0 I was only replying to your remark about the cube. Again, proper reading... |-)
•  » » » » » » » 2 years ago, # ^ |   0 In your comment "I had to read twice to see whether zero rotations would be allowed, but was able to conclude from the problem statement that it was not. The announcement was not necessary." This portion is about problem C.And "And in my opinion proper reading is part of the challenge." this portion is universal as it is your opinion. Generally opinions are global unless you write them in problem C(cube) scope { }. So again erroneous statement...
 » 2 years ago, # |   +19 Enough "IMPLEMENT" dose today, time to sleep.
 » 2 years ago, # |   +3
 » 2 years ago, # |   +2 worst c i ve ever seen so far in my life
 » 2 years ago, # |   0
 » 2 years ago, # |   0 can someone plz tell me why am i getting error in problem C in pretest 7. Here is the code http://ide.geeksforgeeks.org/gZt7f3 Thanks in advance
•  » » 2 years ago, # ^ | ← Rev. 3 →   0 Your solutions fails for test case: 1 1 6 6 2 2 2 2 4 4 5 5 6 5 6 5 1 4 1 4 3 3 3 3 Your output : NO correct output : YES
•  » » » 2 years ago, # ^ |   0 You miss something, this test case is not valid. Because problem says, "There are exactly 4 occurrences of all colors in this sequence."
•  » » » » 2 years ago, # ^ |   +1 Sorry my mistake. I have modified the answer.
•  » » » » » 2 years ago, # ^ |   +5 ai must be in range 1 to 6 (1 ≤ ai ≤ 6)...:)
•  » » » » » » 2 years ago, # ^ |   +6 :P
•  » » 2 years ago, # ^ | ← Rev. 2 →   0 If I correctly understand what you do: A) There are two more sequences for "temp": 3 4 17 19 10 9 16 14 and 1 2 18 20 12 11 15 13. B) Your sequences in "temp" are disordered: for example, the first shoud be 1 3 5 7 9 11 24 22. C) You fill "t" wrong: you should move 7 to 1, 6 to 0, and so on.
•  » » » 2 years ago, # ^ |   0 yeah that 7 to 1 and 6 to 0 is taken care in that for loop. And yeah i ve missed those two sequences. Thanks.
 » 2 years ago, # |   +305 Relevant Meme for Problem C?
•  » » 2 years ago, # ^ |   +3 That is one amazing meme
•  » » 2 years ago, # ^ |   0 You are a god.
 » 2 years ago, # |   +136 I want to explain situation with today's round.Yes, it's unrated and I appologise for it and will try my best to make this never happen again. Despite it, hope you liked the problems.Problem preparation is a very hard process and it's quite easy to make a mistake there. Hopefully, Polygon platform was designed and it helps to find most of errors automaticly. Moreover, before any Codeforces round some people solves it before beginning to make sure that everything is all right. In most cases it's enough to make sure that there are no mistakes there, but today it wasn't enough. Error in stament of problem D today was done during rewriting statemnts from drafts, which happened too late, so most of the testers read correct draft of statement, but not the final version with mistake. Of course, many people read final version of statement before beginning, but nobody noticed that something changed between these two versions.Of course it was a good lesson, and I will try to be much more careful next time.Sorry again.
•  » » 2 years ago, # ^ |   +15 By the way, did you see the problem C? What do you think about it?
•  » » 2 years ago, # ^ |   0 While posting the editorial, I will REALLY appreciate if you guys can help us grasp an elegant way to do problem C (rubick's cube) for this round. My code was all mess (and failed pretest 7 XD) and it boiled down to me not able to implement it elegantly. I will be grateful if that can be considered! Thanks :)
•  » » » 2 years ago, # ^ |   0 my code get accepted in the pretest but i think it will fail in the system testing . anyway my approach is to check if there is only two sides facing each other have the same color .for example if we look at the sample test the side 0 is facing , 3 is facing 4 and 5 is facing 1 .if all numbers in 1 are equal ,all numbers in 5 are equal and there is no other side whose numbers are equal then the answer is yes otherwise the answer is no . sorry for my bad englsih .
•  » » » 2 years ago, # ^ |   +17 You only need to implement only 3 moves to perform all required moves. See my comment below in this blog post. Code: http://codeforces.com/contest/887/submission/32027887Btw, its Rubik's Cube! ;)
•  » » 2 years ago, # ^ |   +3 If author had added the model pictures in problem statement, maybe the testers would have been more enthusiastic and there would be no issues in problem D
•  » » 2 years ago, # ^ |   0 No worries, we understand that mistakes happen. I'm sure you'll proofread everything very carefully in any round from now on!
 » 2 years ago, # |   +1 I like the problems, but I can't see how they were tested by 6 people. Or you mean each of them tested one problem?Also I think changing the author's solution for D to match the problem statement would've been a better decision.
 » 2 years ago, # |   0 WA on pretest 6 on F anyone ?
 » 2 years ago, # |   0 "if the left model from this pair is higher than the right model from this pair."RIP 2 hours of my life used in solving a wrong version of the problem.
 » 2 years ago, # |   +8 Any insight for Problem F, please?
•  » » 2 years ago, # ^ | ← Rev. 2 →   +5 Here is my idea that I think is right but couldn't implement correctly during contest:Lets start by compressing the heights of the models. Then go over each model and find the first and second models to the right of him(I will call them nxt[1] and nxt[2]) that are shorter than him ( you can do this with segment tree). After we do this lets call every model i whose (next[1] — i) > k "bad". Now its clear we must do a swap with a left model that is atmost K models to the right of every "bad" model. After that, I give every model a lower bound and an upper bound of the height of the model he will be swapped with:lower bound — min(a[i+1],a[i+2] ..... a[i+k])upper bound — min( every model that has model i as his nxt[1] and nxt[2] — that model is > k)After having both of these things. I go over every potential left model and find if there is intersection between him and some lower and upper bound. If there is, the answer is yes otherwise its no
•  » » » 2 years ago, # ^ |   +3 Can you explain what you mean by "that model is > k" in your line explaining the upper bound? Thanks.
•  » » » » 2 years ago, # ^ |   +5 Yes. I'm sorry for wording it badly (Don't know how to use LaTeX). nxt[i][2] is the second index to the right of the model i that is shorter than him, right?since we are swapping the nxt[i][1] of that model with someone else, we must rely on nxt[i][2] now. If the distance between i and nxt[i][2] is more than k we must rely on the model we are swapping nxt[i][1] with, and giving it an upper bound( since the model we swap it with will have to be shorter than all models that will rely on him)
•  » » » » » 2 years ago, # ^ | ← Rev. 2 →   +3 How did you solve WA on test 6? I can't seem to figure it out unfortunately, and I can't understand your code.
•  » » » » » » 2 years ago, # ^ |   +5 My WA was that I forgot when we swap the left model must be taller than the right one. And also sorry for the messy code, too much pressure in the last 15 minutes :D. If you have questions regarding the code feel free to message me.
•  » » 2 years ago, # ^ | ← Rev. 2 →   +3 My understanding of task was wrong. Don't waste your time on text below.My idea (http://codeforces.com/contest/887/submission/32033565) got WA at 12 pretest.A) Make array Values[n]: models and designer (zero value).B) Make min segment tree using Values.C) Get last position L in [0; n — 1] where Values[L] <= MinFromTree[L + 1; min(L + k, n)]. It means that model L is not taller than all of k next models.D) Check (L + k + 1) position — position of (k + 1) model after L model:D.1) (L + k + 1) < n // Don't touch designer.D.2) Values[L] > Values[L + k + 1] // Reasonable swap.D.3) Values[L + k] > Values[L + k + 1] // Allowed swap.E) If all D conditions are true, swap (L + k) and (L + k + 1) in Values and tree.F) The same as step C.G) If L is undefined, print "YES".
•  » » 2 years ago, # ^ | ← Rev. 3 →   +10 My short description:A — the leftmost position of model who violates the beauty (a lower model is more than k positions to the right).We must swap the higher model with lower on position A+k — I think I am able to sort of justify/prove that — if it is not possible, NO.Look for the biggest value lower than a[A] to the right and take the leftmost such value — I can't prove/justify that so it might be wrong. Just wrote couple of examples which showed that it was working and could not find a counterexample — call this pos.If there is no pos -> NO.Swap a[A+k] with a[pos] and verify that everything looks good -> YES or NO.Verification could be easily done with segment tree.Could somebody please provide a counterexample or some justification of the above solution? It was accepted: http://codeforces.com/contest/887/submission/32033530Thanks!
 » 2 years ago, # |   +28 I've never been to Div. 1. I have tried, I have come close, but I couldn't. And then today, I performed well at last. Well, maybe the hacks were the main boost today, but still, it's a part of CF, right? And I was happy that at last today I'll be in Div. 1. And then, it was unrated. I know many of you have faced this, but still, it hurts...a lot!!! I just don't know what to say. Guys, before arranging a round, please be careful :( I don't know if I should be angry or sad or frustrated. I know you guys will say, "you will get more chances" and all, and "if you are a good coder then this shouldn't bother you, you'll (should) be in Div. 1 without this", but still, it's painful AF!
 » 2 years ago, # |   +238 When you take this much pain to visualize problem C and the contest is unrated -_- :p
•  » » 2 years ago, # ^ |   +28 hmmm...Handcraft-forces?!?
•  » » » 2 years ago, # ^ |   +3 Yep :p
•  » » 2 years ago, # ^ |   0 Same here, I'm terrible to visualize 3D things, and that question was too boring, just try all. Wasn't a good contest :/
•  » » » 2 years ago, # ^ |   0 only 6 if else conditions are enough to solve this problem.http://codeforces.com/contest/887/submission/32033187
•  » » » » 2 years ago, # ^ |   0 Yes, I know it. The problem was to know the index of the array for each if.
 » 2 years ago, # |   +8 32026568 Check out this AC code for Problem C today. If checking for all rotation was the solution , Then this was the worst Problem C ever !
•  » » 2 years ago, # ^ |   0 oh you should see mine :3
•  » » 2 years ago, # ^ |   0 You had too much hard coding man. That could lead to more errors. Just my takeCheck out this solution (Idk if it will survive system tests) http://codeforces.com/contest/887/submission/32028788
•  » » 2 years ago, # ^ |   +6 Yes, checking for all rotation was indeed the solution. Check out this elegant code: http://codeforces.com/contest/887/submission/32021880
•  » » 2 years ago, # ^ |   0 check out this solution http://codeforces.com/contest/887/submission/32033399
 » 2 years ago, # |   +52 Dear codeforces, you now really need to make a contest this weekend for us to forget about what happened =)
•  » » 2 years ago, # ^ |   +8 Great suggestion :)
 » 2 years ago, # |   0 I lost 15 minutes because first image is wrong in problem C... And that's time to hack and think... :)) :))
 » 2 years ago, # |   +2 This is really disappointing.I mean , first you have rounds in such an irregular fashion (sometimes 2-3 contests in 2-3 days and sometimes 1 in 7-10 days) and then it gets unrated.Surely programming is more about learning new things and contests are a great source for it but what is the point of trying a problem when its not even correct. I believe admins should take care of this now more seriously.
 » 2 years ago, # |   +4 Oh my goodness.Not a nice round,right?
•  » » 2 years ago, # ^ |   +8 I think you are right.
 » 2 years ago, # |   0 Shiram to contestteon
 » 2 years ago, # |   -11 Please make the contest rated. This was my best performance ever. Please :'(
 » 2 years ago, # | ← Rev. 2 →   0 I think it was the worst round of all what I saw. All what I can do after I has been solving problem C is never to go to the Codeforces, I'm sorry authors.
•  » » 2 years ago, # ^ |   0 Well problems E and F were nice. I didn't look at A, B, C and D but the last two problems were much better than in a lot of div.2 rounds — in a lot of div.2 rounds last 1/2 problems are just obvious. In this round the last two problems didn't have an obvious solution at all. So it's wrong judging a round by just the first couple of problems. IMO the contest was nice and I don't see why the round is hated so much.
•  » » » 2 years ago, # ^ |   +35 E is just dirty Geometry.
•  » » » 2 years ago, # ^ | ← Rev. 3 →   +25 It's the very strange position. Why do you forget that this round is definetely not for you? What can do a usual Codeforces Div2 member? Do you really think that they won't hate it, when they had the E and F problems which they knowingly couldn't solve just because they hadn't skill like you, the D problem which was wrong and the C problem which supposed a stupid realization? And what can I say to my pupils? When I will say: "You need to solve Codeforces contests because it's very beneficial for your skill", how will they believe me when they spent 2,5 hours of their time senselessly and they were deprived pleasure?
•  » » » » 2 years ago, # ^ |   +5 Agree. I have just started Codeforces and I was really scared yesterday.
 » 2 years ago, # |   0 Cant you problem setters speak english????
 » 2 years ago, # |   +6 That moment when you open up someone's code to hack, but instead find out locking yours' one was a big mistake :') The round being unrated came as a blessing.
 » 2 years ago, # |   +10 Problem C was irritating. But for an idea you can notice following: Moving right face anti-clockwise is equivalent to moving right face clockwise thrice. Moving right face clockwise is equivalent to moving left face anti-clockwise. So you only need to implement 3 moves!
•  » » 2 years ago, # ^ |   0 You can only solve the Rubik doing one rotation if and only if there are exactly two sides already solved, and they are opposite to each other. With that in mind, there are only 3 possible moves.
•  » » » 2 years ago, # ^ | ← Rev. 4 →   0 Yeah, but in this case you have to make cases on which moves to do, but from what I told, you can implement all the moves using three moves without digging up the cases!Btw its not Rubik, he was the person who invented it, its 2x2 Rubik's cube or Pocket Cube! ;)
•  » » 2 years ago, # ^ |   +1 Plus there were some test cases in which the configuration of solvable cube was not possible Test case 46- 1 1 1 1 2 2 3 3 6 6 6 6 5 5 4 4 3 3 2 2 4 4 5 5 :/
 » 2 years ago, # | ← Rev. 5 →   -24
 » 2 years ago, # |   +4 After seeing C , I really beleive CodingDestroyedMyLife . I was like trying to find some pattern but on seeing other solution,I know It was sh*t :(
 » 2 years ago, # |   -18 "It was at this contest Denisson knew he fucked up." -Morgan Freeman (Red), The Shawshank Redemption
 » 2 years ago, # |   +7 The author got a glimpse into the future, when he set the title for problem D: "Ratings and Reality Shows". An adjusted rewording could be "Reality Shows the Ratings are unaffected".Unfortunately, nobody noticed the forewarning in the title.
 » 2 years ago, # |   0 can 3 digit number be formed in B problem?
•  » » 2 years ago, # ^ | ← Rev. 2 →   +2 No you can'tYou need a minimum of 19 digits to form 99, one zero and two of each other digitsSample test 2 has the largest answer
•  » » 2 years ago, # ^ |   0 Yes, taking one number from each 3 dices
 » 2 years ago, # |   -13 Starting from this contest, I hate Rubik's Cube.
 » 2 years ago, # |   +6 "it using one rotation" It should be "it using exactly one rotation" and highlight.
 » 2 years ago, # |   +7 The goal of the contest should be 'improving problem solving skills' and not just 'improving ratings'. Problem setters must have cross checked all the problem properly because this type of things disappoint a lot, but they are also human and they are allowed to make mistakes.
 » 2 years ago, # |   0 OH! I just notice problem C ask for one rotation And I have written a web pages can show multiple rotating approach.Debugging for a long time, wanna cry, thx for unrated.
•  » » 2 years ago, # ^ |   0 Genuis
 » 2 years ago, # |   +13 The best solution for Rubik's Cube I've found so far: 32027198
 » 2 years ago, # |   0 What is the case for B where most solutions would fail? I got a WA on test 49!
•  » » 2 years ago, # ^ | ← Rev. 2 →   0 The solution for B which got a WA on test 49, that's because you use more than one digits in one cube to build a number. :)
 » 2 years ago, # |   0 http://codeforces.com/contest/887/submission/32028326 It is my solution for problem C and it isn't so hard, I think.
 » 2 years ago, # |   0 good
 » 2 years ago, # |   0 can someone tell me why am i getting Runtime error in problem A on pretest 4. Here is the code http://coliru.stacked-crooked.com/a/5676d8eb514b7ae4
•  » » 2 years ago, # ^ | ← Rev. 4 →   +1 stoi converts string to an int value,so "11111111111111111111111111111111111" falls out of the range
•  » » » 2 years ago, # ^ |   0 any hint to fix it ?
•  » » » » 2 years ago, # ^ |   +1 Operate on string or char array itself . Don't use int/long/long long variable to store the binary number .
•  » » » » » 2 years ago, # ^ | ← Rev. 2 →   0 so how can I store the string after convert it to int ? I think I should change my algorithm ,I'm right
 » 2 years ago, # | ← Rev. 2 →   +18 Prob C is shitty, and one of the most important info is not there, at least before I asked them at 1:30
 » 2 years ago, # |   +26 I really don't understand how the Codeforces Testing system works? Despite having so many testers, why are there such critical flaws in the problem statements?
•  » » 2 years ago, # ^ | ← Rev. 2 →   +3 Statements has changed after testing, that's why nobody noticed mistakes in statements. Of course, changing statements after testing is a bad idea. I hope this situation will never happen again, at least until the coordinator of rounds changes.
 » 2 years ago, # |   0 spending one hour and half to implement B , and i get wrong answer for forgetting a stupid line , i am an asshole
 » 2 years ago, # |   +6 Waiting for editorial of Problem C.
 » 2 years ago, # | ← Rev. 4 →   +3 wup wup that's the sound of the police Just same code... matheuslealv -> 32033737 UmCaraLegal -> 32033714EDIT: Ahh, contest isn't rated. Nevermind.
•  » » 2 years ago, # ^ |   0 Rated or not, cheating is always forbidden!
•  » » » 2 years ago, # ^ |   +27 Cheating at an unrated contest, facepalm
•  » » 2 years ago, # ^ | ← Rev. 2 →   -8 I just noticed that they cheated on problem F. It means that I'm the only person to solve F during contest legally :Pgritukan
 » 2 years ago, # |   0 I saw quite a few requests to get another contest quite soon, to make up for this one. I think that you will not get the next contest too soon if you are down-voting contest authors' so badly.
 » 2 years ago, # |   +16 Basically me in this morning
 » 2 years ago, # |   0 can someone explain why something like that would happen ?I tested the example on codeblocks and my answers were right but im getting wrong answer on problem b my output is not 0.. you can try it on your compiler http://codeforces.com/contest/887/submission/32035119
•  » » 2 years ago, # ^ | ← Rev. 2 →   0 Just initialize s and t. And you don't have to check 0, start from 1.
•  » » » 2 years ago, # ^ | ← Rev. 2 →   0 thx there are several not necessary things or mistakes in my code but i was asking why it's different output when i run this example30 1 2 3 4 56 7 8 9 0 12 3 4 5 6 7i get 87 on my compiler but the judgement protocol gives 0 to my output you can try it on codeblocks it won't give 0 maybe they have something wrong with their judgment
•  » » » » 2 years ago, # ^ |   0 Your code gives 0 in "Custom invocation". As meatrow said, you should initialize s and t (with zero).
•  » » » » » 2 years ago, # ^ |   0 man I hate these stupid mistakes.. there is no need for t too 98 is the highest possible number I fixed it thx for help
 » 2 years ago, # |   +5 It is too much, man
 » 2 years ago, # |   0 unrated! really? -_-
•  » » 2 years ago, # ^ |   0 Yes.
 » 2 years ago, # |   +32 Denisson needed only 1 blog to become the worst contributor :(
•  » » 2 years ago, # ^ |   0 On the bright side, well he did made a new top position somewhere....
 » 2 years ago, # |   +2 CF predictor was showing +7...I could have bacome a pupil after 8 months of Newbie life...."Sigh" Why so cruel
 » 2 years ago, # |   +11 I know most of you guys are disappointed in this round. But lets just appreciate the problemsetter cuz it is not an easy thing to make a round
 » 2 years ago, # |   +5 In problem C some of the test cases are wrong because the 2X2X2 Rubik's cube will be in unsolvable state Test case 46- 1 1 1 1 2 2 3 3 6 6 6 6 5 5 4 4 3 3 2 2 4 4 5 5 this configuration of cube is not possible
•  » » 2 years ago, # ^ |   0 My solution is based on the assumption that the configuration must exist. It passed systests.
•  » » » 2 years ago, # ^ |   +5 you can check the given test case by putting the color values in this site. Such configuration cannot exist in a solvable 2X2X2 Rubik's cube. https://rubiks-cube-solver.com/2x2/
•  » » » » 2 years ago, # ^ |   0 Then bad test cases too :(
•  » » » » 9 months ago, # ^ |   0 hehe, cheating is never good — https://rubikcubesolver.com
 » 2 years ago, # |   +5 76 people got AC on problem D. Did they get it on correct solution or wrong solution? Should I submit D? Is it fixed now?
 » 2 years ago, # |   +11 Too Terrible.
 » 2 years ago, # |   +5 Can anyone explain the solution for D? (The real D, not the D in the problem statement)
 » 2 years ago, # | ← Rev. 2 →   +85 ENG: What is wrong with everyone? Everyone is mistaken. I think the one unrated contest isn't reason to hate author. We learn from mistakes and must support him. Actually, problems were good. One more educational round...RUS: Что со всеми не так? Ошибки делает каждый. Я не думаю, что один нерейтинговый контест настолько большой грех, чтобы ненавидеть автора. Мы должны поддержать его. А ведь, задачи были действительно хороши. Еще один поучительный раунд...
•  » » 2 years ago, # ^ |   +28 I agree, -483 is too harsh. It's not the first unrated contest and won't be the last. I'm sure he tried his best to make it work...
•  » » » 2 years ago, # ^ |   +14 Btw I can't agree that Denisson 's one is more notorious than nssprogrammer 's one. (-688 votes on comment < -483 votes on blog). This is his first contest on codeforces, and actually plagiarism is one of the worst thing in the prograamming contest. This is not plagiarism, or not the worst thing (Half of problems are not bad), so I think the weight of indiscretion is not larger than nssprogrammer 's "Notorious Coincidence".
•  » » 2 years ago, # ^ |   +11 Here the problem is not whether contest is rated or not,but what matters is time.here most of people who are participating after leaving some important work e.g. that time which I should be devoting to prepare for exams, sacrificing the midnight sleep, some may be having a very tight schedule after job, and they are doing contests instead of relaxing and spending time with family. In such a scenario, It definitely hurts if u have to spend 2hrs unproductively.
•  » » » 2 years ago, # ^ |   0 But it means you should care about risk of this. If I encountered in the same pattern I would think that "it's unrated, but it's just a coincidence. I should think about the possiblilty of unrated (note that it doesn't mean I will ask whether the contest is rated or not)". That's one of what programming contest stand for, I think.
•  » » » » 2 years ago, # ^ | ← Rev. 2 →   +10 Sure, it's always a risk whenever you do anything. But if there's a bad contest of course people will downvote for the wasted time.
 » 2 years ago, # |   +12 When will the editorial be published?
•  » » 2 years ago, # ^ |   0 In case you havent found it out yet here it is. (http://codeforces.com/blog/entry/55584)
 » 2 years ago, # | ← Rev. 2 →   -50 Denisson I'm getting WA on test 37 in D. Is it my bug, or is the problem still not fixed?I was just being really really careless.
 » 2 years ago, # | ← Rev. 2 →   +5 How To Solve Problem B?
 » 2 years ago, # | ← Rev. 2 →   +5 Can Someone Explain Problem A Div 2
•  » » 2 years ago, # ^ |   +16 First of all, 64 = 1 000 000 We need to find position of the first '1' at the string, then just calculate the count of zeros between pos and length of string. If we can make 1 000 000, then the answer is "yes"
•  » » » 2 years ago, # ^ |   0 Thanks.
 » 2 years ago, # |   0 When is the editorial posted?
•  » » 2 years ago, # ^ |   +8 Editorial is already published:http://codeforces.com/blog/entry/55584
 » 2 years ago, # |   0 Wow, I noticed that the problem A, C, D (problem which the factor of downvotes) was made by ayoyia, not Denisson, by seeing editorial. I think his responsibility is light and should not get too much downvotes.
•  » » 2 years ago, # ^ |   +15 I really don't think that the fault rely in only one person, please stop point fingers.
 » 2 years ago, # |   -8 I really enjoyed problem C. I would like more such problems in contests. But most people dislike C.
 » 2 years ago, # |   +23 It is Codeforces Round #444, the 4th problem went wrong, and now this post has 444 downvotes!
•  » » 2 years ago, # ^ |   0 And it is 4 days ago :)
 » 2 years ago, # |   0 it's unrated , i am a little uncomfortable.
 » 2 years ago, # |   0 Denisson just turned things up..From -102 to +18...
 » 2 years ago, # |   -11 What was this contest? How could have anyone allowed the setter to propose these problems?
 » 2 years ago, # |   +3 Why a lot of minuses? Because it isn't rated ?! If it will be rated, you will say "It's unfair". Or because system was bad. Can you make system like it, if no, respect other people's work!
 » 7 months ago, # |   0 I found it not the contest blog with the most downvotes. For Codeforces Round #571 (Div.2) has surpassed this!