:""

Wow, So exciting to see this round, I hope it will be interesting.

This round will be tasty if all problems cooked by sevlll777.

Why so many mysterious ppl living in Antarctica

hope i can reach Specialist this time

as a tester, I loved the tasks

I hope it will be great contest and get more points.

Hope we'll get delta +

How is the rating system?

Will the rating still roll back? It's been a long time since I've had a rollback it feels like

Akbar udachi

I feel so happy when you said the statements short ... Thanks

Good luck everyone!

Hope the fast editorial, not too fast eventually :)

I wanna reach pupil :') hopefully i dont mess this up

I want to back Red by CF908 before my last ICPC, Shenyang 2023. Good luck!

It's guaranteed that statements are understandable, short, and, of course, ✨ stylish ✨.

sevlll777 roasting Codeforces on Codeforces. Less go!!

3-second-forces

D and E are too tough for me. Hopefully my current points are sufficient to become dark blue after the round.

Worst contest I've ever seen!

What is the point? Details and implementation?

Please be aware of your problem's quality before you bring it out!

You are wasting 20000+ people's time and feeling!

Div2D was too easy to be D!

What was that A ^-^

I love this contest, because it is very tasty!

How to solve C?

1A is interesting, 1BCD is implementing race.

Errichto leaked the solution of problem A: https://www.youtube.com/watch?v=F4rykKLcduI&t=374s The question was similar though

Best Interesting contest Ever, I love it. But the worst thing that from problem A to D in Div.2 was leaked in youtube and this thing waste others effort So be good and don't copy answers " You are just deceiving yourself :)"

What is Div1 lol, B > C > D in terms of difficulty. Most of my time on Div1D was trying to prove why the obvious approach wouldn't work since it feels way too easy for its spot in the contest.

I think the contest was great. Maybe its true that D was too easy but I am happy for my first A-D in a Div2 round

Wow, this was a very weird contest for me. I don't know why but I stumbled so hard on the first problem itself.

Where did the [3,2,3,4,3] array come from in the first test case example on https://codeforces.com/contest/1894/problem/C ?

Very nice problems! I also seem to remember I liked some div2 contest from you. Well done!

I feel that div1D is too easy, and it can be easily implemented using a greedy simulation approach.

Div. 1C seems too straightforward for a Div.1C, you can basically figure out 80% of the solution right after reading it.

Some people says that problem Div1B/Div2D is implementation heavy, but here is my solution:

• Sort array $$$[b_1, b_2, \cdots, b_m]$$$.
• Now we can assume $$$b_1 \geq b_2 \geq \cdots \geq b_m$$$.
• For $$$i = 1, 2, \cdots, n$$$, do the following thing (initially $$$\text{cur} = 1$$$):

1. While $$$b_{\text{cur}} \geq \max(s_i, s_{i+1}, \cdots, s_n)$$$ is satisfied, append $$$b_{\text{cur}}$$$ to answer and add $$$\text{cur}$$$ by 1.
2. Append $$$a_i$$$ to answer.

• Lastly, append $$$b_{\text{cur}+1}, b_{\text{cur}+2}, \cdots, b_m$$$ to answer.

For example, if arrays are $$$a = [7, 4, 5, 1, 2]$$$ and $$$b = [3, 9, 8, 0, 6]$$$, the answer is as follows:

• First, sort the array $$$b$$$. The array will be $$$[9, 8, 6, 3, 0]$$$.
• Then, add all elements in $$$b$$$ which is greater than $$$\max(a_1, a_2, a_3, a_4, a_5)=7$$$. The current answer is $$$[9, 8]$$$.
• Then, append $$$a_1$$$ to answer. The current answer is $$$[9, 8, 7]$$$.
• Then, add all elements in $$$b$$$ which is greater than $$$\max(a_2, a_3, a_4, a_5)=5$$$. The current answer is $$$[9, 8, 7, 6]$$$.
• Then, append $$$a_2$$$ to answer. The current answer is $$$[9, 8, 7, 6, 4]$$$.
• Then, add all elements in $$$b$$$ which is greater than $$$\max(a_3, a_4, a_5)=5$$$. Nothing will be added.
• Then, append $$$a_3$$$ to answer. The current answer is $$$[9, 8, 7, 6, 4, 5]$$$.
• Then, add all elements in $$$b$$$ which is greater than $$$\max(a_4, a_5)=2$$$. The current answer is $$$[9, 8, 7, 6, 4, 5, 3]$$$.
• Then, append $$$a_4$$$ to answer. The current answer is $$$[9, 8, 7, 6, 4, 5, 3, 1]$$$.
• Then, add all elements in $$$b$$$ which is greater than $$$\max(a_5)=2$$$. Nothing will be added.
• Then, append $$$a_5$$$ to answer. The current answer is $$$[9, 8, 7, 6, 4, 5, 3, 1, 2]$$$.
• Lastly, append all remaining elements. The final answer is $$$[9, 8, 7, 6, 4, 5, 3, 1, 2, 0]$$$.

What's the solution to problem E?

My approach was to check for a fixed len was to check number of elements of value len we are forced to take for every multiset. These values will change only in multisets in which element len is present, so I am recalculating in that only and I am handling overflow by using int128. And I am checking for len E [minimum len, min(min len+m+1, maximum len)] Is the WA on test 2 related to int128?

This was a decent one. Thanks a lot for the problemset. Hope i can reach CM...

Who let him cook?!

implementation round and speedforces. Not a good idea to put all these tasks in one round.

I was bamboozled by D, worth a ton of points, but easier than B and C xd

It turns out that I've submitted two exactly the same solutions to problem Div.1 B 231765593 and 231765621 due to internet connection errors on the cf side and they counted as a resubmitted solution, so the corresponding penalty (-50) applied. Is it possible to cancel one of these submissions so that the penalty would not be charged (because under normal conditions codeforces would not allow submitting exactly the same code twice)? sevlll777

Really nice contest and interesting problems. Thanks a lot!!!

Problem A must be 3500

I would not say that this is the worst contest I've ever seen in my life. Cause apparently, there are also many, many, 74TrAkToR rounds before.

sevlll777: I hope you will like the problemset and ideas hidden in the problems! It's guaranteed that statements are understandable, short, and, of course, ✨ stylish ✨.

Div2A: What is the point of put "It is guaranteed that the given sequence of plays corresponds to at least one valid game scenario, for some values of X and Y" and "? — if it is impossible to determine the winner of the game" together in statement? It's not short enough?

I feel almost A(21min) = B(34min=55-21) = C(27min=82-55) = D(22min=104-82).

A: Interesting, but little bit heavy implementation for D1A. (my approach is SCC+BFS)
B: One idea task, but it's not easy like AGC-A. Great!
C: Small data structure, but it's almost logic test.
D: PROOF BY AC (I think it's around 1500pt to just get AC)

And one another thing, it seems no one got FST in Div1. Congrats!!

great contest!!!

Kinda feels like people who say that the problems are obvious implementations mean that there is an easy-to-believe greedy... For example, it would be very nice to see an easy solution* (and by that I obviously mean that you can rigorously prove it, otherwise it is a heuristic, not a solution) for the problem (div1) D. And B. And C.

Would have been better if div2D/div1B problem had explicitly mentioned LIS contains strictly increasing elements :( Got solving the wrong problem the entire contest.

When will the rating be updated?

Div2 A should be better ;(

If you think you're stupid:

231749854

Statements are ✨ stylish ✨ indeed.

round was a bit speedforces, but problems were nice!

I liked the problems, but statement of Div 1 C drives me crazy. Math-heavy explanation of simple things does not sound like fun. I don't mind the formal definition of things, though ideally they should follow the explanation you can relate to, not substitute it.

"Minimize anti-beauty" sounds like double negation in some sense, why inventing a word? If you follow the statement style it should've been called f(S). If you want to make it prettier, call it "ugliness of set" or "cost of set".

third question was fabulous

A and C questions are awesome!!! 💣💥

Div 2A was inspired (perhaps a little too straightforward-ly) by this YouTube video (featuring Errichto)
Errichto's interview with Joma Tech

The question is mentioned by Kamil at 4:23, when he gives an example of competitive programming questions.
Seemed like a really fascinating solution to me even when I had first seen the video.
Side note: The hints in the Editorial mention tennis and volleyball, quite like how they were brought up in the above-mentioned video

Division 2, problem A tricked us into believing that there will be a case where the answer to the problem can be "?". If that were not mentioned, many of us would easily arrive at s[s.size() — 1] solution.

A similar problem as problem A, with the same solution, was mentioned in this interview with Errichto

yayy I became expert! Thanks for the contest.

I'm not really sure about it, but I think that again I wasn't able to get AC because of worse constant factor ;_;

Got stuck on memory limit too. Especially (I think) the stuff about doing something like that:

void rec(int v) {
    if (v<=n) rec(v+1);
    if (condition) {
        //something that creates variables and releases them right after this block
    }
}

I've knew before that if it wouldn't be inside of an "if" statement then all the memory would be allocated right after entering the function and I guess that the existence of the "if" statement doesn't change much. Can somebody confirm?

I've discovered this fact painfully in other problem some time ago, where the condition was called only a few times, but because of this insta-allocation my solution was quadratic instead of something faster. Here it just made constant factor bigger (and memory complexity just like time is still linear), but ML also turned out to be too tight for me.

so ✨ stylish ✨

i got the idea of div2 c but it was too late till then .

anyway i'm happy that i got positive delta after performing such badly :)

Deleted

The overall difficulty distribution for the Div 1 is more like a Div 2 contest.

Normally Div 1 contest has several 3000+ problems. But we only have 1 this time.

Actually E is hard, Which makes the gap between D and E huge.

I think the problem D should appear in MO but not OI.

i want to know why all numbers is same ,ans is -1 i do not understand

Nice problems ... Thanks !

If problem A for 500 points requires 2 additional explanation messages, then the problem has nothing to do with "guaranteed that statements are understandable".

Thanks for this round. But the statement of task A wasn't short.

The first two problems of Div 2 needed some proper explanation.

Dear sevlll777,

Please tell me how can i take a part of creating problems for any upcoming codeforces Round (Div. 4) ...?

Thanks in advance Dear..!

Took me almost 2 hrs to solve C during the contest, but after the contest, solved D in around 15 minutes. :(

LOL, the problem A in Div2 xDD I've heard it so many times, it's a running joke among my friends lol

Difficulty level of Div2 D is 1700, I think it should be lesser than 1300.

I enjoyed solving Div2 B, C & D, but for me problem A was confusing.

A is the hardest problem in DIV2 LOL

Statement in Div2 A problem belike

@sevlll777 in question A of this contest .Suppose we have a case where AAAB (or let's say)AABB

then for which x and y will B win these cases?

Update : Deleted

Its been so long since we have given any contest, when is next div1 or div2 contest, I think its been about a week right, they should have already posted announcement for next contest, no? What is schedule of contests on codeforces.