are you retarded.

another speedcoder?? btw is F an ad-hoc? I simply didn't understand how the official editorial works

ai cheaters exposing themselves

"Closest Moment" is another masterpiece after "RLE Moving"

In a rated contest, you can open problems only after you choose Rated or Unrated participation. If you don't choose an option and five minutes have passed after the contest starts, you are considered Unrated.

F<<<<<D

upd: i can somehow understand that D is much easier than E in thinking of their solutions, but how the hell is a linkedlist F? in terms of thinking F≈D and in terms of coding F<<<<<<<<<D

lol ksun48 was beaten black and blue by newbies

I really can't understand these people... Isn't this like asking "how to run in 10 seconds in the 100 meter race"?

for those who are "planning to be a IGM CF user" while still being a newbie, imo they are either retarded or extremely arrogant that they never have the ability or patience to be one.

bro, English is not my first language, so you really can't expect one to remember what a "trapezoid" is while learning "梯形" in Chinese.. I also mentioned above that

Different cultures define a trapezium slightly differently and many have the term trapezoid too

, so I wonder why no one else faced the same problem...

Thanks, that hurts a lot (TAT)

You're right... i googled and the most of the results are correct...

but i also found this:

What is the definition of a trapezium? Is it a shape with exactly one pair of parallel sides or at least one pair of parallel sides? Or maybe even none at all! Different cultures define a trapezium slightly differently and many have the term trapezoid too. In the US (for some) a trapezium is a four sided polygon with no parallel sides; in the UK a trapezium is a four sided polygon with exactly one pair of parallel sides; whereas in Canada a trapezoid has an inclusive definition in that it’s a four sided-polygon with at least one pair of parallel sides — hence parallelograms are special trapezoids.

this might explain baidu's weird results.

Did anyone faced similar situations in E?

I searched "trapezoid" in baidu, a Chinese search engine, and the first result was called "不规则四边形", which means "a flat shape with four straight sides, none of which are parallel", and I couldn't understand the example or its explanation, which also didn't explain what a trapezoid was...

I only understood it after seeing its further results called "a flat shape with four straight sides, one pair of opposite sides being parallel and the other pair not parallel". What's more, the online translation websites in China also gave me the first result I mentioned, so many other participants might be puzzled.

Wow that is quite amazing... maybe you should add a spoiler for this

that is called multi-edges.

search "AC-predictor" in greasyfork.org and download the userscript (you need to install tampermonkey in your google first)

got stuck on both C and D... there a ~3000 rank and ~600 performance gap between those who finished ABCD fastest and slowest...

but the official editorial didn't use binary search either, why does its logic work then

I used basically the same approach as yours. idk either

He is Jiyu Shen (emptyhope), with CF rating of 3000+, but it seems that he was unable to attend the contest

It seems that you didn't knew about this.... He got disqualified for being caught with cellphone.

Yeah exactly. I also found a problem MYQ10, where repeated memsets will cause TLE. I did know the omitting low trick could save memory, but I didn't realize it actually avoid repeated memsets in multiple testcases until I read an editorial.

consider the example [1,1,-1,-1,-1,-1,-1], where a GP couldn't be constucted.

wtf why on earth is this G

yeah, it would be much convincing if the evidence is visible by everyone, and it won't do much bad.

well what about that

ok now i'm convinced that you are totally lying...

huh, is that allowed? I really didn't know...

Well, then you'd better reflect on yourself...

In Codeforces Round 1028(Div.2), you used python for A and B, and on C you also used it for the first two submissions. But on your third and fourth submissions you switch to C++ IN TWO MINUTES! What kind of people would do this?

However, I admit that I haven't found concrete evidence to prove you cheated. You may explain for this, and point out where I am wrong.

upd: You're flagged by the cheater detector extension, so they probably have concrete evidence to prove that you cheated... I'll ask them for the evidence and see whether you could argue for that.

What do you mean by "must"...

I mean, by posting this comment, did you "propose their own idea or suggest for any improvements" yourself?

When you cheat in a contest and got detected, this contest will not be rated for you and this is called "skipped".

Well, is it possible because your program went wrong in some other places? Maybe you can show me your submission.

long long should be used. There are at most $$$10^5 - 1$$$ edges, and each move costs at most $$$10^4 \times 10^4 = 10^8$$$, so the result may cause integer overflow.

E is much easier than regular Es, over 3000 people solved it! Maybe it's the most solved E in ABCs. But that caused a speedcoder for those solved E and couldn't solve F. I got 2239th for solving ABCDE (but I even got 2187th for solving ABCD in ABC403), too bad :(

upd: people who solved ABCDE can get a perf ranging from 1059(2734th) to 1529(1036th)...

Yeah, downloading testcases can be extremely useful. There are so many problems where I got all the examples correct and some of the testcases wrong, and couldn't find out the problem for a long time. Sometimes it is so hard for you to construct a example to hack your program that it's nearly impossible to debug it. :(

Yeah, but what if it is a much more important contest, like ICPC, IOI or other official contests? When you meet problems halfway or simply encountered bad problems in these contests, you certainly can't choose to quit. The point of taking contests in Codeforces, (I think for most people) is to prepare for these important contests right?

Overall what I want to express is that doing this is just like placing a bet and withdrawing it after a while, and that putting the unfairness aside, this system is certainly not applied to most official contests and therefore shouldn't be applied to Codeforces as well. "Unsportsmanlike" is kinda just a softened version of "bad". (just my opinion)

bro definitely should work on literature, working on cp is totally wasting your talent XD

ABC395D probably, because the 3 mappings it constructed is quite subtle and requires more logical reasoning than an average 350-point problem.

This is frustrating. I've never understood how Codeforce's voting system could work like this. Is Codeforces really a chaotic system where you get totally different votes despite posting the same thing?

Examples of this can be seen everywhere, like this one. This even happens to official accounts like luogu_official! And in this post, it is literally the same thing, and there's nothing wrong with the contest (it even hasn't started yet). The worst thing is that you don't even get a reason for that.

If it's really the case, then there's no point in setting the contribution system. I don't know how you can stand this.

btw, if you want to downvote me, please upvote me; if you want to upvote me, please upvote me; if you don't want to vote, please upvote me.

yeah exactly. I kinda figured out how to use A,B,C,D to express to answer, but after I had written all the combination number stuff, I found that it was totally wrong. After the contest ended I went to see the japanese editorial and had no idea how it worked. Can anyone tell me pls

UPD: Now kenkoooo has updated all the problem difficulties. It really helped me a lot (in tracking my progress effectively, choosing problems that are suitable for me and so on), so it was really relieving to see the chart coming back :)

But why hasn't anyone explained what caused that? Before that I thought there is a web crawler or something that works on its own. I was recommended to use clist.by instead, but I wasn't really used to it. What's more, I can't figure out why I get -8 votes for my second comment. I was just trying to prove https://atcoder.jp/posts/1457 doesn't explain anything.

This article seems to be AI-written(just my guess). No one uses bold when writing a post.

When I typed in "tourist", it gave me a bunch of nan-rated problems.(Just curious about why)

[there should be a screenshot, but i am not allowed to use photos:(]

What are u saying? I think it is obvious that if your rating is below 1200, you can't get rated(which means it is not recommended for a coder with rating below 1200 to take part in it).

Also, if a 700-rated coder can be rated in ARC, he/she can get a performance of about 1000 without solving any problems.

But isn't CAPTCHA only used when one is submitting code, not when one is looking at others' submissions? What's more, kenkoooo stopped updating since ABC397, which is much earlier than the publish date of this post.

bro are you farming negative contribition? cuz you are now the 3rd worst contributor XD

Anyone knows why kenkoooo hasn't been updating the problem difficulty for nearly 2 months (since ABC397/ARC195/AGC071)?

The problems of ABC402/ABC403/AGC072 is also not shown in the chart.(Though I can see my submissions on those problems in /user-submissions.)

No offense, but it's more than radical.

How can Codeforces get verifiable government-issued ID from every country? I mean, do you expect Codeforces to contact with all governments around the world? Even the United Nations can't do that at all.

In China, some apps(like online banks) do require users to link their accounts withs their ID cards and now they have introduced facial recognition system to make sure they won't use fake identity. This is surely a safe way to 100% make sure whether one is believable or not, but using this in not so credit-related websites such as Codeforces(after all, cheating can only result in a fake rating) is way too far.

You can see the explanation I gave here. I think most people are stuck at the D=0 corner case and the D>=1 DP method (instead of greedy approach).

POV: You are refactoring you code and saw vector<ll> b(n);

You: OMG this bad variable name is freaking me out! I must change it to vector<ll> a(n); or I would die right away. XD

bro thinking that he can avoid being accused of cheating by saying "I don't have time to argue with you" and then never replying again lol.

bro thinking that he could prove that he didn't use AI by saying "I clearly know what my code does". lol

This is ridiculous. Nobody cares about this "name rating", and your insisting in continuing this would only prove that you are talking nonsense.

No. Look at the example I gave below, I think it suggests that a greedy approach can't work this out because sometimes two adjacent elements should be deleted altogether.

Fyi I think an example would help you to understand the DP:

In a chain where frequencies of all the elements are {1,100,1,1,100,1}, the minimum deletions would be 4, by deleting all 1s. That means you shouldn't just consider deleting all even elements or all odd elements.

Many people got stuck in this problem because they failed to notice the D=0 corner case (like me). upd: The D>=1 part is a bit complex too. My solution is to first collect all the numbers that occurred in the sequence A, then I find out all the "chains" (for example, {3 7 11} is a chain when D=4). Finally, I compute the minimum deletions of each "chain" using DP. I use dp[0][i] for the minimum deletions in the first i numbers of the "chain" when number i is not deleted, and dp[1][i] for the minimum deletions in the first i numbers of the "chain" when number i is deleted.

Problem D is so hard! I cant understand why I always get TLE.

Yours doesn't seem good either. In my view, the word "testers" should be "participants".

But are the downvotes voted by Chinese? upd:I think it's actually not so necessary to downvote comments that isn't so readable, especially when you are not participating in the contest mentioned in this post and is just downvoting for their bad command of English.

Why is most of the comments in this post downvoted? Is there anyone doing that on purpose?

As a Luogu user, I think there are also many high-quality problems and contests in Luogu. Hope you guys like it XD