কি অবস্থা মামা? (That's Bengali for "What's up dude?")

I am super excited to invite you to participate in Codeforces Round 735 (Div. 2) which will be held on Jul/29/2021 17:35 (Moscow time). This round is rated for future LGM participants whose current rating is $$$\le 2099$$$.

You will be given $$$5$$$ problems and $$$2$$$ hours to solve them. All the problems are authored and prepared by me.

I would like to thank -

- antontrygubO_o for his awe-inspiring coordination of the round
*and rejecting my problems, and thus hurting my feelings.* - Um_nik, _Ash__, Anachor, Arg_007, Alpha_Q, DAleksa, steinum, Tasdid, border, mk_Shahriar, t17, imAnik, Alfeh, Aritra741, FrozenBlood, SajidZakaria, ovis96, PritamDas, Raiden, YoyOyoYOy000y000 and tdpencil for testing the round. They were excellent testers, so they deserve the upvotes that they will be begging for in the comments.
- The great MikeMirzayanov for the amazing Codeforces and Polygon platforms.
- You, for existing and participating in the round. Also, thanks for giving your best to try to achieve everything you set out to do. You will eventually be happy. Just hold right there.

The statements are super short and I have tried to make the pretests strong. I encourage you to read all the problems ~~and solve them all~~.

I would like to dedicate this contest to the fallen king, my father, who died two months ago. May he and all the departed good souls rest in peace.

Scoring distribution: $$$750 - 1250 - 1750 - 2000 - 3000$$$.

Good Luck!

**UPD1:** Thanks for participating, I hope that you guys loved the problems, and sorry for B being a bit difficult than usual.

**UPD2:** Editorial

**UPD3:** Congratulations to the winners.

Div.1 + Div.2:

Div.2:

Also, congratulations to the first solvers:

A: LiM_256, at $$$0$$$ mins!

B: RinShima, at $$$4$$$ mins!

C: xiaofan7, at $$$7$$$ mins!

D: 6945930042DucLA, at $$$7$$$ mins!

E: rainboy, at $$$23$$$ mins!

whoa!

ok lesson learned don't write comments

.

It's a reply to the first comment of the blog. Like this is the reply of your reply.

The same way as my comment is in one of the top comments of this blog .

P.S. it's a reply comment brother

Just forget that.

A

Bangladeshiround after $$$7$$$ years. As aBangladeshi, it feels very special. Eagerly waiting for it. <3Speed forces it is.

No, this is not a speed forces. Problems are very interesting.

what is speedforces

5-question contest or so.

whenever people say interesting problems then it means it takes a lot of efforts from them to solve.. So GG

Didn't aged well.

That......... that might be difficult.

We are also super excited to participate!!

The problems are super interesting. As a tester, I encourage everyone to participate (and also upvote this comment :3).

your wife is really beautiful in your dp

Thats probably his younger sister

A lot of upvotes and testers are highly recommending it... I think everyone should give it. I will also give... :)

The problems statements are very clear and precise. Hope everyone will enjoy the round. And also, don't forget to READ ALL PROBLEMS.

Eagerly waiting for this round

Noticed this in the blog? :P

Eagerly Waiting for this round ! খেলা হবে মামা !

Pls no fst pls no fst plsssss

I almost fst is related to getting wrong answer but please tell the full form of fst.

PS: I DON'T SPEND MUCH TIME IN CODEFORCES COMMENT SECTIONS

FST-FAILED SYSTEM TEST

Your contribution is contradicting this statement.

Thanks for this delightful invitation, and for sharing with us the kind dedication to your father's soul.

RIP. He's looking at you from heaven :)

oh hoo!! The first bengali round I have seen so far. Feeling very proud.

A Bengali round with Bengali problems ... (expected) :)

Shei

May

Allahrest your father's soul, Ameen.Is it usual that i just edited my message once and it repeated 10 times ?

As a tester, I really liked the round. The problems are very nice (Do give a read to all of them). The statements are short and concise.

Also... as a tester, it is my duty to inform you there's an upvote button to this comment... UwU

as a tester, I recommend this contest to everyone.

খালি আপভোট পাওয়ার ধান্দা...

please upvote and stay tuned

HA HA

অস্থির (amazing)

As a Bengalee,I am very glad to see the starting line of the blog is written in Bengali.Hoping for some exciting problems.

I am going to participate in this contest(& lose some rating!).

May Allah grant your father Jannatul Ferdous.Ameen.

Super Excited!

Pro A : 250 and Pro A : 750 :V

Nice to see a Bangladeshi Round

Time to upsolve this and this round

I see what you did to Anton :)

SpoilerSelect the invisible line ahead of Anton's mention

I was wondering why people are talking so much about that line. Now I realize it's in white font and I'm in dark mode, so it appeared normal text to me.

Wow that was very motivating!

Proud of you. Best wishes for you. I am Eagerly waiting for this round. Hopefully i will enjoy the problem set. (আসো খেলবো,খেলা হব্বে ২৯ তারিখ)

Already feeling like it's gonna be a great round.

One of the sweetest invitation ✨✨✨

As a Codeforces Optimal Theme user I see this!

We can also drag it to see the rest

look It says "antontrygubO_o for accepting all of my problems at gunpoint".

Hope that Bangladeshi round will be held more often beginning with this round.

I am seeing "কি অবস্থা মামা" in a Codeforces blog!! What a pleasure for eyes!! Not going to miss this contest at any cost.

pari na pari ,khela hobe !

5 problems & 2 hours is the best format for a CF round. I don't know why this is so rare nowadays. Hope this will be a great round. Best of luck.

As a Bangladeshi this is a very mesmerizing news. This will surely encourage Bangladeshi contestant to be more precise on this competitive filed. Proud to be a Bangladeshi. Congratulations to you all and we are very honored. Wising best of luck to everyone. Hopefully this will be an interesting contest. Waiting to be a part of this historical journey..

YouKn0wWho orz!

Love from Kolkata(India) <3

Kya hal h bhai ke (that's in hindi for what's up dude)

I would like to dedicate this contest to the fallen king, my father, who died two months ago.Sorry to hear about this. May his Soul Rest In Peace.

Thanx For the Round BTW

Very excited to participate this round!

Omg! Bangla Brigade on fire, so many comments within 2hrs!!

As a

YouKn0wWhoFan I highly recommend participating in this round, he has authored many lovely problems on CodeChef and toph.co before. Super excited for this round!Let's hope problems are as interesting as this announcement was.

a great contest for us. thanks

ok.

When author says "I encourage you to read all the problems"I managed to solve the last problem in Codeforces Round #714 (Div. 2), though I was a Pupils at the time!

SpoilerBut I got a Wrong answer on test 97 after pending system.

My Code

So everyone should read all the problems and try to the last moment!

Did you have a hacky solution or just random thing which passed pretests or was it actually something close to the editorial's solution?

It's a lame solution. It only checks $$$10^8$$$ pairs, and that's enough for random tests but it can be easily hacked.

That applies to specialist like me also.

That applies to a pleb CM like me also lol. Let's be real, if you can solve div 2E consistently, then you are at least master level.

Agreed (esp. with the "at least" prepended to master). I still can't solve div 2E consistently

lighthearted memeIt's Bengali! I am so excited!!

YouKn0wWhoorzHow did you change your text color?

like this probably:

$$$\color{white}{\text{like this}}$$$

put this :

`\color{white}{\text{like this}}`

inside of`$$`

$$$\color{pink}{\text{Thanks :D}}$$$

Thankyou for the contest YouKn0wWho.Very much

excitedfor it.How did you change your text's color?

Using html

Okay does other contest blogs have hidden texts too? I discovered this for the first time;_;

This is really impressive! Eagerly waiting to participate and get mara :3

Hopefully , going to be a exciting round . And my deep condolences to you and your family .May your father's departed soul rest in Peace.

Never seen A problem with 750 points, its gonna be crazy ride.

May ALLAH Grant Your Father Jannatul Firdaus, Brother. and I am having a great feeling that the problems will be very interesting.

Yes your father is a real king, rest in peace.

Wish to participate in your next

round.Best of Luck for the

ICPCYouKn0wWho .hi um new here:)

Good luck on your first contest :)

Eagerly waiting ... hope to regain my lost position in this round (T~T)

mama?

Real meaning of mama is maternal uncle. But people of Bangladesh love to address friends, any unknown person as mama. This is a common thing in Bangladesh.

This is really a proud moment vai.Waiting for it!

More power to you!!

Being excited, motivated, happy, and sad at the same blog

I'm sure your father is proud of you

God bless your father

"The statements are super short and I have tried to make the pretests strong."Orz

The score distribution seems to be quite difficult than usual.

I like short question descriptions very much

same here.

What a wonderful line to read before the contest.

Excelsior to take part and face new challenge adn learn from them, hope you have not added any question from xor

My 100th Round in Codeforces is going to be a Bangladeshi round,really!!! As a Bangladeshi i am really excited!

As a fan of Hero Alom, I can't wait for this round. I love Bangladesh.

Really proud of you, man! YouKn0wWho ❤️

Trying selecting the first line under "I would like to thank -". Hahahaha

He is legend in codeforce i try to follow him..i solved acroding to his 1st submission!congrats mann!

Expect! First time to participate Bangladesh round :)

You are proud son of your parents. RIP to his soul

Bangladeshi round => Comment section fully immigrated.

RIP for your father. His thoughts and blessings will be always with you.

I love the way you bring this contest to us. Stay strong and good luck everyone!

As a tester, I recommend you to read all of the problems

the best tester

Better than Um_nik

thanks

God bless your father

I don't think I'll ever manage to reach LGM. Will this contest still be rated for me?

Jokes aside, really excited for what I think is the first contest with the standard 5 problems in 2 hours format in a while!

It seems that problems will be interesting. Mercy and forgiveness for your father.

Bengalis, assemble.... খেলা হবে । সবাই খেলবো ।

Let's go amigos.

"The statements are super short and I have tried to make the pretests strong." After this line, there is no doubt that the round will be marvelous.

Also, this round is being felt vary native to me. As a Bangladeshi, I seriously feeling proud.

As my father also died 4 years ago, I can understand your feelings. May Allah give Jannah to your father.

love Bangladesh from Iran

ok

Voldemort's contest it's gonna be tough

Short problem statements! I am expecting maths problems.

Thanks for keeping the statements short! :D

Eagerly waiting like everyone! :) Hopefully It's gonna be a nice contest!

Lets make it to 2000+ upvotes

May he and all the departed good souls rest in peace.

iakioi

Anybody noticed this on the first line in Thanks section

antontrygubO_o for his awe-inspiring coordination of the round

__****and rejecting my problems, and thus hurting my feelings.Yeah, everyone did. Stop writing comments about it.

Most people like: go to comments to watch testers comments and understand if the round will be difficult or not. Wish you will grow your rating (my eng is bad, I know)

Good luck, Guys!

Well, this contest is probably rated for me because I'm a future Legendary Grandma.

I hope that I will like this contest, and not only me. I wish your father peace in the other world.

Good luck for all.finally,

div1.5(according to scoring)

Will it be a mathforces ?

Good luck to everyone!

Did anyone see the hidden text in the blog. It reads:

antontrygubO_o for his awe-inspiring coordination of the roundand rejecting my problems, and thus hurting my feelings.Just select the above line :P

hope that i will become expert today :)

good luck!

Good luck, Guys!

Good Luck!

Hoping A, B and C questions would be easy for a noob.

`Hope is a bad thing!`

Oh I will not become a LGM in the future, so the contest is unrated for me!!!!!!!

Try to copy al text and you will see an invisible text after "antontrygubO_o for his awe-inspiring coordination of the round" .

Even though I quit CP 2 years ago. Still going to participate. Proud!

A<<<B drastic rise from A to B

Don't leave a single question easy make all of them hard. So I can finally quit! first question take 2 min rest --------- its like an appreciation token for participation. Codeforces is a platform where top 2000 people solve question rest all see the standing page after doing A question. Again div zero contest. There is no coolness in setting a hard contest , it should be a balanced one . increment in my preparation <<<<<<<<<<<<< increment in hardness. A year ago when I knew nothing i was able to solve at least two A B and C if its of graph or standard one. Now after months of practice I'm able to solve only A . A contest is of 2: 00 hr for me its of 5 minutes . Thanks codeforces for demotivating me again! For people less than 1500 its is buzzer round who solve A faster. thanks queueforces for ruining this buzzer round also.

Do not get frustrated buddy. There will be some easy rounds you can increase your rating in those rounds.

AforcesHardForces IT IS!

suorer baccha contest

Why the problem B and C are too hard, frick this? Btw I'm saying this just bc I was not able to do problem B and C :(.

Ikr.. even I wasn't able to do them. Probably some trick / method that I've never seen before. Unlucky :(

Nevertheless, hoping to learn some useful stuff from the editorial

prob C is easy if u just generate xors for yourself, it's some weird series of number, but in some time you should be able to find pattern in it (i started this too late)

i found out that for numbers 0-15, 16-31, 32-47 etc difference between MAX and MIN is always 16

just look at it:

n = 3 m = 47

3 2 1 0 7 6 5 4 11 10 9 8 15 14 13 12 19 18 17 16 23 22 21 20 27 26 25 24 31 30 29 28 35 34 33 32 39 38 37 36 43 42 41 40 47 46 45 44

n = 20 m = 47

20 21 22 23 16 17 18 19 28 29 30 31 24 25 26 27 4 5 6 7 0 1 2 3 12 13 14 15 8 9 10 11 52 53 54 55 48 49 50 51 60 61 62 63 56 57 58 59

it must have some sort of pattern

I tried this for 1.5 hour straight, couldn't find pattern to conclude ans.

13k participant only 2k solves for B, Great demotivation.

Yep, what a round to pick to come back to CF after a 5 year pause lol

and they said global round B is hard how about this B :P

Please give a hint for B :(

It's a troll problem. :p

I get that part plz give a hint

if n is large then last two indexes mult by example will give very large number and k is at most 100

idk what happened, D was much easier for me than B and C, couldn't solve them yet... :/

bitwiseForces

sadforces

Problem D is easier than B and C(Unless I FST)

D > B > C

How to solve E?

Only divisors of N-1 are important. Find array d[i] = number of arrays where i divides all elements (the answer is easy to find from that array). d[1] = 2^(N-1), all other d[i]'s are either 0 or 1 (proven by the following checking algorithm): start from leaves, it is uniquely determined whether that node is selected before it's 'parent' (k cannot divide both x and x+1). If it divides neither it's 0, if the check finishes it's 1.

Whaaaat? Why $$$d[1]=2^{N-1}$$$?

Ok, I understood. I read the statement incorrectly, I thought that the numbers are written in the operations' order, not in the vertices' order.

Did the same thing :/

Me too :(. I spent an hour trying to mess around with permutations and random $$$dp$$$ states after figuring out the sum of $$$a$$$ was $$$N - 1$$$.

To be honest, that was only an intuition during the contest, basically, for every edge you have options for which ending node you select first. Since it's a tree there will be no cycles, so it's a good ordering. My first idea was $$$N!$$$, but that didn't work with sample. Probably double counting something. Definitely not a proof, let's wait for editorial :)

As _Ash__ wrote below, it's simply the number of ways to orient all edges. In different ways there are different arrays, that simply follows from a mathematical induction like one you mentioned — starting from leaves and rising up.

You can transform the situation a bit like this: You have a tree, and you have to make each edge directed. The value of each node is its indegree. The problem becomes a lot more approachable now.

Nice round Thanks! Was the pretended solution for B brute force from n — 200 to n ? or will it give TLE in system test?

Difficulty in my opinion: E > B > C > D > A, B is my nightmare, the most right thing that I do is to skip B after 40 minutes of struggling.

In problem D you just need to know one trick: A string that contains n number of "a" and n-1 number of "a" separated by others (like 'bc' or 'b') can satisfy the condition.

Like I have wasted about an hour over B then I have come up with this solution. Link to Solution

Still, I don't know what's logic behind this solution.

How to

judgeD...?Just a plain suffix automata and check if every node occurs an odd number of times in $$$\mathcal{O}(n)$$$.

I think B was too difficult.

No, easy-peasy bruteforce

Can you share your thought process on solution for B?

$$$k*(a_i|a_j)$$$ is small ($$$<1.5*10^{7}$$$) relatively to $$$i*j$$$, so lets maximize $$$i*j$$$. For that check all pairs $$$(i, j)$$$, where $$$n-1000 \leq i,j \leq n$$$.

1000 is overkill. I believe 200 is enough.

Doesn`t matter.

But don't do 2000 because you will TLE on test case 51 :(

In the problem k will be k<= 100 but how can you say that

(k*(ai|aj)) will be less than 1.5*10^7.$$$a_i \leq n \leq 10^{5}$$$

$$$a_i|a_j < 2^{17} = 131072$$$

nice problems with short statements!

I know editorial will be here soon but I can't wait how do you solve A

Of all the consecutive element pairs, choose the one with the greatest product.

can you post your code

My Solution (O(N) Complexity)

Cmpare products of adjacent numbers of the array...and no idea abt others..xD

Problem statements were short and concise,but round was tough.

Another Ehab in town ?? Well I liked the problems though, worth brainstorming!

Yes Another ehab I think so

BIT-forces

It was very memorable round.

another div1 Contest.Hahaha

How did you solve B ?

Check all pairs from the right-most one (N, N — 1).

As K cannot be greater than 100 and Ai || Aj will always be strictly less than 2N, a brute-force solution should work.

The loop is to be broken when the maximum possible value for the current pair is lower than the current max value (max. possible value would be i * j — k * 0).

Thanks , I was not able to make that observation

I just searched in last 1000 elements but i don't think it will pass main tests

Edit:it did pass but barely

it will pass. Check for last 200 would also lead to the same result

1e7 operations should pass easily

Well I'm searching in O(n^2) but the sum of all elements is 3e5 so it's 3e8

Wow, that was a very beautiful E problem, thank you! All around the round was nice, though for me D and B should've been swapped in difficulty...

Also, codeforces is very weird with rating around 2100, it's much easier to drop to high 2000's and get a bunch of rating in div2, than to get rating in div1 with low 2100's.

How does titles of tasks related to each other and tasks itself?

Best Output Format Ever

RIPBitwise-operator.would rather suggest to make it unrated

I don't know why but Codeforces felt like Atcoder today!!

BNotice k<=100 and a[i]<=n. Let's fix index i and find j(<i) such that i*j — k*(a[i]|a[j]) is max. maximum value of i*j is i*(i-1). So every time j decreases our main function value will decrease by i and what if value of i is large. maximum value of (a[i]|a[j]) is n. Let's assume a[i]|a[i-1] = n and i*j — k*(a[i]|a[j]) be f(j). If there is a j such that f(j)>f(i-1) then

i*(i-1) — k*n < i*j — k*(a[i]|a[j])

let the a[i]|a[j] be 0

i*(i-1) — k*n < i*j

i*(i-1-j) < k*n

So for every i calculate answer f(j) such that i*(i-j-1)<k*n

CThe statement boils down to — we have to find k such that (n^k) is minimum and k>m. Let the value of k be pow(2,33)-1. Iterate from 32 to 0 and check whether replacing the ith bit of k with the ith bit of n doesn't change (k>m).

DAnswer is of form a+b+c where a and c are strings only consisting 'a' and their length differ by 1 and if n is odd b = "bc" else b = "b"

For n<=2 find the answer separately.

https://codeforces.com/contest/1554/submission/124184154 sorry for this stupid question, but for question A, I don't understand why it get diff ans in testing, I got the correct ans in local. (g++ 14)

Long is int on Codeforces testing system. Anyway, long isn't enough to keep 1e18. Use long long instead!

Tasks were really good, my mind became more powerful, thank you! And accept my condolences about your father.

A :)

B :|

what's wrong with my solution: 124171044

for n>1000 you never compare the last 2 numbers lets say. Imagine a test with 1000 of 999 and last 2 numbers 0 and 0.

i'm in 0 base index system.! so i think last 2 numbers should compared.! can you explain little bit more!

Change long to long long. https://codeforces.com/blog/entry/93237?#comment-822571

in java long == long long int

I really think that s the problem because the rest seems ok.

you probebly get an overflow when multiplying (i + 1) * (j + 1)

Horrible round to me, only thing I could do was blaming myself...

Sorry for the first version. I don't want to explain what did I think that time.

The round have two problems of Bitwise-operators, and they are hard for people like me to solve. And I think so many great participants lost their ratings in this contest, so maybe we can make this contest unrated for them.

But you ask me... I think it's okay to keep this round rated. But I suggest, don't write those problems in one contest again!

What do you mean by "too many"? Did any other problem involve bitwise operators apart from C?

I am hoping an amazing editorial from YouKn0wWho

Really suggest making this round unrated.

sadge spent 2 hours not realizing loop variables i * j overflows :(

`This round is rated for future LGM participants whose current rating is ≤2099`

But it is

advisedthat you are already LGM before attempting ;)Serious point: interesting problems, short statements, but this is probably too difficult for a Div 2 round.

Wow, these were REALLY short statements

A-D(hoc)ForcesHow to prove that time complexity of B is

not O(n^2)YouKn0wWho ??Lets take if you take $$$i=n, j=n-1$$$ the worst case gives you as a result $$$n(n-1)-k(a_n|a_{n-1})$$$ with $$$a_n|a_{n-1}$$$ maximized. It's easy to check that $$$a_n|a_{n-1} \leq 2n$$$ so you know that $$$n(n-1)-k(a_n|a_{n-1}) \leq n^2-n-2kn$$$

Lets take $$$i=(n-a)$$$ and $$$j=(n-b)$$$ and take the best case= $$$a_i=0, a_j=0$$$, you get $$$(n-a)(n-b)=n^2-(a+b)n+ab$$$.

Now the key observation is to notice that:

iff

iff

which is true if $max(a,b) > 201$ so you only have to check the last $$$200$$$ elements of the array

Woah!!This was an amazing round,lived up to the hype.

Instead of solving E, I think it's quite more interesting to think about how to write the checker of D.

Suffix automaton? We just need endpos set size of each node.

Probably. I think SAM is the best way to finish the checker.

I misread problem $$$D$$$ and before solving it, I've solved a different problem which was quite interesting, so I'll share it:

The problem is the same, but instead of $$$N$$$ beeing the size of the string, let $$$N$$$ be the sum over all occurrences of strings only consting of one character. And $$$N \leq 10^{12}$$$ seems to fit

I'm curious how the system tested in D. Maybe using suffix automaton?

In problem B, since

`0 <= a[i] <= n`

, we have`a[i] | a[j] <= 2n`

and`k*a[i]|a[j] <= 200n`

. Then for big enough`n`

, let try all pairs among last`m`

indices (we will choose m later). We can prove that the result will be in there. The worst case for last two indices is:`n(n-1)-200n`

(and notice that the answer is at least that number). The best case for the uncheck indices is:`(n-m)(n-m-1)`

. We need to have:`n(n-1)-200n >= (n-m)(n-m-1)`

or`n(2m-200) >= m^2+m.`

In the contest, I choose`m=400`

with`n >= 800.`

Very nice problems, although I feel like the position of B and D should be swapped. I especially liked C. The statements were so short it felt like I was solving AtCoder problems. Thanks for the contest!

MikeMirzayanov I submitted A at codeforces.com and I got a server error, so I went to m2.codeforces.com and I submitted it there

the same exact codethen codeforces.com started to pick up and my code for A actually went through despite the server error I got. now, what happened is I have the same code uploaded twice and the system skipped the first submission and judged the second one which leads to less points. my submissions:https://codeforces.com/contest/1554/submission/124135925

https://codeforces.com/contest/1554/submission/124135472

Fixed. Ratings will be adjusted automatically after I'll process cheaters.

Thanks a lot

Anyone noticed that ,there's no

Successful hacksin this round!!!There is.

I saw someone hacking $$$2$$$

BsFinally a great contest with very strong pretests!

May your Dad rest in peace my friend YouKn0wWho, he should be proud of you

Problems were really good.Thanks.I personally want more contests from you YouKn0wWho

Is anybody able to help me understand what is wrong with this hack generator? It says "Validator 'Validator.exe' returns exit code 3 [FAIL Expected EOLN (test case 1, stdin, line 3)] close" It is for problem B

Fast Editorial！ SpeedForces！

To not keep you waiting, the ratings are updated preliminarily. In a few hours/days, I will remove cheaters and update the ratings again!

hello Mike.. Why cheaters are not removed from the last 2 rounds??? I saw plagarised solution but still that person is rated

What's the point of setting problems in this manner. There should be a certain level of uniformity in the increase of the standard of problems. Can't just set a problem having a rating around 1000 and then just move to 1800-2000 rated type problems. Looks like the problem setter was just trying to show off his skills.Totally demotivating for newcomers. There should always be a balance among the distribution of problems. I urge MikeMirzayanov to not allow these kinds of people to set problems for such a highly rated platform who just want to show off their skills and nothing else. I believe that even the high-rated coders will agree with me on this point.

You know, it's hard to aproximate the difficulty of a problem with only a few testers. Nobody is trying to show off anything, other than the abillity to create problems with short statements and good pretests.

Nice problemset but days like these i wish to kill myself

Time limit are too strict for python which cost me C problem for this round.

I got tle for my python solution https://codeforces.com/contest/1554/submission/124177594

where as when submitted same logic in cpp it passes. https://codeforces.com/contest/1554/submission/124191191

Please give some extra time to python coders and please try to keep time constraint flexible for every language.

Great Round! Problems were good and required thinking! I found problem B to be the best! (out of A B and C)

SOS solution for B without taking into account the small k 124191286

Very cool.

May I ask your idea?

SOS's Blog

Thank you!

982ms that was close enough lucky you...

It is a perfect guide how not to make contests. All problems except D are complete trash, you just look at them and instantly realize they are trash.

Why are they trash?

Because they match the typical patterns of bad problems:

You, being a coordinator, must know it.

It's a pattern of good problems

No. Reread and pay attention to the word "complicated".

Most problems match those patterns, just usually implicitly. In this case, the statements were simplified so that you don't have to go through trashy stories to get to the problems. I think a majority of people prefer it that way. Problems C and E especially can be rewritten in a way that are less explicit, the author just chose to present them like this (and I prefer it that way).

It's the solutions that matter, not the problems.

How is "yaaaazaaa" a valid answer for n = 9 in problem D. Isn't substring "aaa" occurring twice in the string??

3 times: twice at aaaa and once at aaa.

Got it. Just having a very bad day today :(

Alhamdulillah!!This is the contest I have been waiting for so long!!! finally I am blue and that's also in a contest organized by a programmer from my own country. I will never forget this day!!

Thank God I skipped this one.

I got a high rank in this Round,but I still think this Round a not really good one.That is,Problem E is too easy as the final problem of a Div 2 only Round.

Besides,Problem D is too easy.I think it will not be harder than *1200.

orz,you All Kill

I totally agree.The problems D&E are much easier than the past contests.It made this contest another speedforces.

I agree

you are masters :|

maybe, if div2 round was too easy, participate in div1?

He said this Div2 is easier than

the pastDiv2.And I think so.How can Karry5307_AK_NOI2023 solve C at 00:16:27 and solve D at 00:16:13?

Just because he is Karry5307

Just because he is Karry5307

Just because he is Karry5307

Just because he is Karry5307

Just because he is Karry5307

Just because he is Karry5307

Just because he is AKSSH5307

Just because he is Karry5307

Just because he is Karry5307.

Just because he is Karry5307.

Just because he is Karry5307.

Just because he is Karry5307.

Just because he is Karry5307.

Just because he is Karry5307.

Just because he is Karry5307

Just because he is Karry5307.