Azerbaijan team:

• Aykhan Damirli (dmraykhan) — 2nd time at IOI, 0 attempts left
• Hasan Valiyev (Hasanv) — 1st time at IOI, 1 attempt left
• Ali Aliyev (Nxxlt) — 1st time at IOI, 0 attempts left
• Elvin Imanli (Captain_Georgia) — 1st time at IOI, 0 attempts left

Team selection was based on the combined scores of two selection rounds and a bonus score derived from the Grand Prix results): https://aze-selections2025.codeany.org

I appreciate your reply — thank you!

Qingyu, Will the test cases for the tasks be published? Making the Ucups archives open and publicly available would greatly benefit the community by allowing participants to learn from past tasks, improve their problem-solving skills, and refine their strategies. It would also enhance transparency and fairness, making the competition experience even better for everyone.

I don’t believe that’s the case. There were multiple meetings at ADA University and other locations, followed by extensive negotiations. Reference: https://x.com/fismailzade/status/1884879439240007757

Fantastic news! A warm welcome to Azerbaijan, dear finalists! We’re thrilled to have you here and wish you an unforgettable experience!

Fikrat_Asadzadeh, Hasanv, rahidilbayramli, coolboy19521 will win Info(1)Cup! Let's go guys! You are the best!

dario2994 Where is possible to download test cases ?

MikeMirzayanov, when submissions of other participants of this round will be opened?

How to solve Čokolade, and Neboderi ?

Can you give, constructive feedback, on why you don't like the eolymp ?

You can find them here https://ejoi2022.org/past-contests/

If you observe you can see that the minimum answer for each node, is the level of dfs tree. For example, the root is level 1, its neighbourhoods have level 2 (level of parent + 1) and etc...

The maximum answer for each node( let's say the node v), is if you visited all nodes in other subtrees and in the last way coming to the node v. We can calculate it by following the formula: Let's say that the subtree with root v has dp[v] children. So the maximum answer will be dp[1] — dp[v] + 1. It means that you have already visited all nodes except the children of the node v. dp[v] can be calculated by just easy dfs. It is classical.

int dfs(int v, int p, int lv)
{
  level[v] = lv;
  int res = dp[v];
  for(auto to: adj[v])
  {
    if(to == p)continue;
    res += dfs(to, v, lv + 1);
  }
  dp[v] = res;
  dp[v]++;
  return dp[v];
}

Thank you for the great explanation mango_lassi!

Thank you for the solution to problem B! cristian1997

How to solve Problems: (L) Fenwick Tree, (J) Elden Ring, (B) Beautiful string? Also, it is interesting for me, is there any alternative solution for problem (S) Two Sequences (I solved it with the help of KMP, it is classical and can be observed quickly, but maybe there is something alternative)?

Thank you for the interesting contest! How to solve L and N as well from Div 2 ? Actually, L is an easy problem, but it wasn't clear about the ace card in the statement. And also, it isn't clear in N, can we have double points for C and D?

I got it. I haven't seen that observation. Thank you again Petr !

Wow, thank you for such an amazing explanation with observations Petr !

Hyeong ko_osaga, can you share the test cases?

Thanks for the exciting contest! How to solve M and F?

998batrr, will be test cases and jury solutions added?

No worries about security. Just use the password that you don't use anywhere.

Are testcases available ?

Thank you! 감사합니다

Hyeong ko_osaga, can you share the test cases?

arthurconmy here . Next round is on 7 November.

Wow, great solution. Thank you Qingyu !

How to solve Beautiful Numbers from Div2, Or Machine, Periodic Ruler ?

Or Machine looks like a grap. In Beautiful Numbers I tried greedy in multiset by finding the closest groups such 91, 82,73 and etc.. ,but it doesn't work.

Better to ask here site-register@opencup.org. Cordinator of your region must register you.

I would be thankful, if someone, maybe from Div1 will help me to understand the solution.

And what does this function fc(y) mean? As far I understand it doesn't count loose. Qingyu

Know, everything is clear for me about convex hull trick. But how that function is corresponded to this trick ? Where is k,b,x ? Qingyu Endagorion

nocriz what about making group open-source repository for saving this list ? Everyone will be able to pull and update this list. I am actively participating these days, I can keep track of it.

What about of updating this list ?

You are welcome !

Div2 O: Let's just simply check all permutations of digits (0, 1, 2, 3, 4 , 5, 6, 7, 8 , 9) and find the permutation, when it is possible to obtain the maximum value. Code

Div2 P: Obviously we want to delete as much as possible. For this case let's observe what will be if we achieved to the panel '<' and our direction at that time is going right, so it will turn our direction to the left. If we will not have '>' we will exit from game and we will not be able to delete as much as possible. So obviously our answer will be the panels which have pairs(means that each '>' has his '<' from the right, one '>' can have 2 '<' and vice versa) and some part if there is, from where our player will run out. By some observation it will be seen that mostly center will have pairs and some parts from right or left may have panels which don't have pairs. So we will choose the maximum part (the left or right), actually we will choose the maximum count from where we will exit if such parts exists. Code

There is another greedy approach for Q.

Is there any other approach for E exempt the editorial's version ? Maybe, it is possible to find the answer with other strategy.

Is there any other approach for A exempt the editorial's version ? Maybe,it is possible to construct the answer in other way.

Thank you Qingyu! Nice observation ! We misled some points in our approach.

I tried to implement various greedy algorithms, but they don't work.

How to solve problem Q(Delete Files) from Div2 ? Is it greedy or DP ?

Thank you Qingyu,bkbtpout! It is clear now.

Maybe someone from Div.1 will be able to explain this problem ?

Thank you AmDer !

AmDer Can you send your solution ?

In problem G, it is not clear how to build the convex hull as for the set of points from example, it will be the monotonous ascending function. Is there any other explanations for problem G ? Endagorion Qingyu

for N, it is possible to use BFS also.

Thank you ATSTNG ! Obviously, linked list is better than set.

Thank you Qingyu ! Very interesting observation.

Thank you bicsi !

How to solve problems G from Div1 and M from Div2 ? Our team thought may be random will work for M.

How to solve problem D? MO algorithms gives TLE. I have an idea with Merge Sort Tree(as segment tree,but we store elements) . Will it pass ?

Sure, EOlymp is very popular in Azerbaijan. One of the EOlymp admins is the professor of the ADA University, famous coach in Ukraine Mykhailo Medvediev. He made EOlymp popular in our country. At the moment all students of ADA university have their assigments there, also schoolers prepare for their competitions on EOlymp.

Hopefully, it will be uploaded on EOlymp. I will write here, when it will be ready.

Azerbaijan team:

• Aziz Huseynov — KalasLavas
• Said Nasibov — snasibov05
• Emin Orujov — E1e3
• Amin Jalilov — Collypso

How to solve I ?

Were there errors in tests with problem S ? I have seen people passed it only after making +60 , +30 submissions.

Thank you Benq Benjamin for the solution .I got it . We wrote dp on prefixes . it was our mistake .

How to solve problem C (Choose Two Subsequences) from div1 ? We thought about DP ,but we didn't manage to solve it. We got WA2. Um_nik , tourist , pashka, Ra16bit .

Thank you for detail explanations awoo , Ra16bit , mnaeraxr !

How to solve problem A (Arrange And Count) from div1 ? We thought about DP ,but we didn't manage to solve it.

Were there wrong ideas that passed ?

Thank you paula ! I liked the contest .

Thank you Arkham_Knight !

Will be there editorial ? How to solve Bajka and Papričice ? I got partial points only (20,50).

Good luck on IOI Domen idk321 ! Don't worry and have pleasure, when you will be solving problems . It is important too .

When i was on IOI , guys told me to solve more old IOI problems, because there are can be something new techniques or new ideas . Also to take Bronze medal you must solve one easy problem full and to solve a lot subtasks as lot as you can.

Thank you !

no , you can copy from 14th line till 87th .

It will be very good if the tasks difficulty will be some more from our rating . It will be not very hard for us . Also thanks for the platform bicsi !

then , i advise you to download test cases and then upload it on hackerrank . In hackerrank , you will able to solve it .

you can find them on codeforces here

Colin thank you for your useful tutorial ! You can add this problems https://mirror.codeforces.com/blog/entry/52492 .

everything is ok now . My internet failed me.

I can't join. I guess, the link's time expired .

Hi Jan! I like very much your explanations! It will be very interesting to listen your explanation for problem Info(1)Cup 2017 Xorsum or similar to Codeforces Round #626 Div2D and Info(1)Cup 2019 Cat .

LoNgLoNgDoUblE J's solution https://mirror.codeforces.com/blog/entry/77187?#comment-619345

Thanks mnaeraxr! I understasnd .

How to solve Problem Q(Easy Puzzle) ? And the problem J(Program Optimization) can solved with Cartesian tree ? Because my solution for J with segment tree gived TLE ,because we have a constant when two position updates and it will be 2*log2(n) .

tumaryui thanks man !

How to solve Problem O(Official Visit) ? How we can construct path ,so it will be maximum?

Hi ! I want to help and test problems ,but i have one question . What time will the testing deadline be?

will be there editorial ?

Thanks for sharing your experience !

There are a lot of method . I will tell about my solution. If there are n verticles so we have n*(n-1)/2 pairs that theoretically can have a short distance 2 ,but graph must be connected . So i constructed a graph where all edges are 1 j (2<=j<=n) . This graph will have (n*(n-1)/2)-(n-1) pairs and their distance are 2 . It is maximal number of pairs can be. So if k>(n*(n-1)/2)-(n-1) answer is -1 . if k<(n*(n-1)/2)-(n-1) we must create ((n*(n-1)/2)-(n-1))-k triangles (cycles) .

How to solve last problem ? I have some ideas ,but i had a little time to think on them.

JanchoMath here https://www.ejoi2019.si/

no problem , glad to help you

EJOI 2018 here (on codeforces).

But, if you want to look on old problems ,it is here (on mendo)

Azerbaijan First Team:

• Abutalib Namazov TooNewbie
• Murad Eynizade wthIC
• Ibrahim Taghizade ibrahim001
• Farhad Azimov farhad13

Azerbaijan Second Team:

• Huseyn Hajiyev computerbox
• Aziz Huseynov KalasLavas
• Fatima Omarova star_eyed_girl
• Amin Jalilov Collypso

thanks forgotter, i will try to understand it. Do you see my insert function ? I think all problems in this function. I think ,i implemented it very bad.

I don't know ,how i can do this. Can you show ?

oversolver can you explain , how is it work ?

TooNewbie , why is better to go first to the farthest one , then to the nearest ? When i wrote first to the nearest one ,then to the farthest , it gives TLE . Maybe ,the best do it random ?

thanks Emilbek !

Will be there editorial and will be possible to finish the problems ?

oh ,really . very interesting to know that. Thanks very much ! :)

thanks very much ! :)

me too