Hello Codeforces!

flamestorm, mesanu and I want to invite you to Codeforces Round 964 (Div. 4).

It starts on Aug/06/2024 17:35 (Moscow time).

The format of the event will be identical to Div. 3 rounds:

- 5-8 tasks;
- ICPC rules with a penalty of 10 minutes for an incorrect submission;
- 12-hour phase of open hacks after the end of the round (hacks do not give additional points)
- after the end of the open hacking phase, all solutions will be tested on the updated set of tests, and the ratings recalculated
- by default, only "trusted" participants are shown in the results table (but the rating will be recalculated for all with initial ratings less than 1400 or you are an unrated participant/newcomer).

Additionally, there might be problems that are interactive, so please read the guide of interactive problems before the contest.

We urge participants whose rating is 1400+ not to register new accounts for the purpose of narcissism but to take part unofficially. Please do not spoil the contest for the official participants.

Only *trusted participants of the fourth division* will be included in the official standings table. This is a forced measure for combating unsporting behaviour. To qualify as *a trusted participant of the fourth division*, you must:

- take part in at least five rated rounds (and solve at least one problem in each of them),
- do not have a point of 1400 or higher in the rating.

**Regardless of whether you are a trusted participant of the fourth division or not, if your rating is less than 1400 (or you are a newcomer/unrated), then the round will be rated for you.**

Many thanks to the testers: Dominater069, Qualified, Vladosiya, qwexd, Gheal, cry, haochenkang.

We suggest reading all of the problems and hope you will find them interesting!

**Good Luck!**

**UPD:** Editorial is out!

nice round

Let's see how many 1400+ rated coders will make a new account.

hosh1zora is an alt acc of cayaxi09, pls ban him.

cayaxi09 — For You

this will be a great round

Much more than previous rounds? wow XD

as a tester, i didn't set anything

hey, im new (2nd contest) so kindly help me out, i solved 4 out of 8 questions, my rating didnt increase yet. Does it take time or is there some other problem. My rating is 380 currently(less than 1400).

Hi, it usually takes about a day to update the rating.

As it is explained in the announcement, after the round there is 12 hours long hacking phase, where participants can hack each other's solutions. After that, all solutions will be checked one more time, so rating changes will be visible in about 16-18 hours.

it has been more than 24 hours now, still the rating has not reflected on my account yet. What about you guys?

After the contest there is 12 hours of hacking. After hacking there is system testing (currently been running for > 12 hours now).

Seems like system testing should finish in the next 1-2 hours, after that they need to calculate rating updates. So rating should be updated in the next 12-24 hours.

why my current submissions are in queue for a long time any maintenance?

Participating unofficially :D Have fun yall

Yay! I always enjoy Div3 / Div4 round

first time i participate in a round unofficially, good luck everyone

I understand that feeling! :3 Good luck, m8! Don't listen to haters.

purpose of narcissism, lol

Specialist earning their respect (^_^)b

Mastersin almost every round.Hope to reach expert after this

Top 50 finish it is

What a confidence. Good luck then.

Thanks, I solved all problems! Carrot shows +150 so seems like I won't make upto expert though.

I Hope to solve at least 4 problems in this contest, so that i can reach Pupil

I will come here after the contest

My first round, wooh hooh!!

Btw this is 1400 point round, so can I earn max of 4200 point in 3 games and surpass tourist ?! /j

That's not how it works

Whaat! Looks like my master plan failed before 1'st round..It's conspiracy against me I will tell you , XD

That’s not how it works man

Seems like it won't be rated round for you... You need a history of 5 rated rounds already. Paradoxical, but that's how cf works. Compete in 5 div 2 rounds or smth, but first — good luck on this one!

Read the bold line, it is rated for him. There is no sense in making contests (especially Div 4, meant for newbies) unrated becuase they have not participated in any rated contests xD

Got it. That's actually good to know!!! Since I have friends that have 0 to 3 rated rounds in their history...

It is rated for him, the point is that his performance in this round will not affect rating of the other Div. 4 contenders since he won't be on the official placement. This is made for smurfs in newreg accounts to not ruin fair Div.4 contenders' rating

Hope to reach 955 rating after this.

Only +1 rating ? lol

newrate=min(newrate,955);

goodluck fellow doktar

hope to reach 669 after this

hope to reach 700 rating after this. Whiss me luck

GL everyone, hoping to reach Expert after next contest

no you wont, I bet

I feel like he will (look at his ratings)

He'd need 202 points to make it to Expert :) (stop downvoting justnemat he's just made a mistake)

welp, not expert yet but close enough i guess

Thank you for everyone's effort to hold this contest. Let's go!!

I will be playing Titled tuesday tomorrow, Sorry, I won't be able to participate this time. flamestorm mesanu

what are you doing here ? go prepare for candidates 2026

div. 4 >>>>

Is there any DIv.5 on codefroces ?

Nope

After this Div4 round, participate in an upcoming div1 round!

fine?

My second contest... HUrrrrraayyyyyyyyy!!!!!

Good Luck Everyone! (Hoping to reach newbie after this)

is it rated?

only rated for tourist

if your rating is less than 1400 (or you are a newcomer/unrated), then the round will be rated for you.

Hope to reach pupil.

Hope to reach candidate grandmaster after this contest.

Goals beyond our understanding

Good luck

how many point i will get if solve all problem ?

if everyone solves all, probably a negative delta

hope to reach pupil in this contest!

hope to reach Specialist in this contest!

hope to solve all problems in this contest!

good luck!

Good luck to us! I believe I will make >1200

big potato

Hope I don't need to leave codeforces after this contest.

I hope, this will be the last rated div4 for me

This will hopefully be my last rated Div4:)

As a tester, this round is very nice :)

what do you mean nice?

Problems are nice!

Maybe the authors are also nice.

No greetings to MikeMirzayanov?

-1000 social credit

-1000 aura

-rep from Mike

oh bro your comment in here https://mirror.codeforces.com/blog/entry/132213

I will solve all under an hour!

i visited your profile.. you never solved all problems... speed is only your handle, lmao :)

interactive problems!!! we are cookedGood luck to everyone

is it rated for me?

I suppose not

Why not?

Because your Rating is above 1200

Oh I'm sorry,your Rating is below 1400,so you can be a rated participant.

Yes

Interactive at Div.4? o.O

Is this the first time in Div.4 to have an interactive? If so, I would be really curious to see what it'd turn out.

It is not the first, here is an example: https://mirror.codeforces.com/contest/1807/problem/E

Woah, I actually solved it and didn't even remember. Cool then :D

Hope it's my last div4

Good luck!!

This is the first contest blog I have seen with no thanks to Mike.

if a 1400+ rated, participates with new account

thenHE IS GAY.Hope to be Specialist after this contest.

I solve all the problems!

Congratulations bro. Bro will now become specialist!

YOU'RE NOW A SPECIALIST!! Let's goooo orz

hope to reach 1000 rating after this.

hope I can participating unofficially next div4 round

hope I will gain some rating through Div.4 contests which don't occur very often.

interactive problem for newbies and pupils. I think if newbies or pupils who can solve interactive problems, mostly the cheated or it's alt acc

you want to say , in div 4 it only comes a binary search or two pointers and nothing more advanced , because it only rated for pupils and newbies?

Good Luck and Have Fun!

For the ones new to cpp and may not know much about interactive problems and flushing->

You dont have to flush the output when you are using "endl", just dont define endl as "/n" like many(including me do).

"\n" ?

ya my bad, i just use endl so dont remember if it is back or forward slash F

Hope to reach pupil after this (to solve >= 5 problems)

same but my rating is too low :(

after long time

easy round

Yeah

upvote if it's your first rated div 4

As a non-tester and non-participant, I would like to test future rounds (I never tested any round yet).

Let's go coders

As a pariticipant, LaLeii orz

As a participant, DangKhoizzzz orz

chikien2009 hello

hello

Da fuq, i think i cant solve all problem because of interactive problem, i hate this

What the fuxk I already see a solution stream by an Indian on my YT main page.

I really hope to become pupil or at least cross 1100 after this round. I am stuck between the 1000 — 1100 range for a very long time

why is queue infinitely long

Queueforces

Queueforces

"queque"

lol. I didn't realize that I misspelled it.ty

Inqueueforces

Testing system is so overloaded that my solution exceeded compilation time: 274812981

lol

Yeah, something happened, we will find such submissions and rejudge them

Queueforces..

Irritated with queue

queue time is enough for me to playing a quick football games ;-;

For ABCD, I spend much more time stuck in 502, 504, 405, etc. than solving problems

Never make problem like B anymore...

Why is cloudflare necessary (Genuinely asking)?

To prevent DDOS Attack. But It defeats the purpose if it actually blocks/delays real user submission.

Exactly :( each time i try to submit or refresh it takes longer time

My first ever AK!! Very nice problems :) especially G2

u obliterated the whole round :)

B>G1

got WA 2 times on B kek

I hate problem B

hint for GProblem E!

Bro how to do B

check for all 4 ways

bruh thats what i did

submission:274947222

you didn't handle the case where 1 round win and and 1 round draw

oh, my dumbass thought you had to win both rounds in order to win the game

https://mirror.codeforces.com/contest/1999/submission/274813505

why this fail?

`if(a>c && b>=d)ans++;`

it can also happen that $$$a = c \ and \ b \ > \ d$$$

similarly for other case's

you can do it like this

`a>=c && b>=d && a+b>c+d`

was a hard one, i did A C D then B https://mirror.codeforces.com/contest/1999/submission/274893746

it seemed like you could do 2 ways * 2 but somehow it didnt work and i used a python code to try to see if the implementation worked then coded it in c++ but the code was only O(N) so i just sub'd the py code, here ya go

(a,b) and (c,d) | (b,a) and (c,d) | (a,b) and (d,c) | (b,a) and (d,c)...check for all 4 combos if answer comes and print accordingly

what is wrong here guys there is a run time error but I deleted my ncr and I used one from the internet and still run time error https://mirror.codeforces.com/contest/1999/submission/274946181

It could be that ncr should return zero if r is not within 0 and n inclusive.

Div. 3/4 interactive = $$$O(logN)$$$ with binary or ternary search, classic

At least it can be easily stress tested, which is good

solving till F. still rank in 4000's );

easiest round imo where "hardest" task is low blue.

got the formula for problem F, failed to solve the modulo thing... sadge

how to solve B ??

Why is Problem G two parts? Is there really a solution for G1 that will not pass for G2?

binary search on a and always take b = 999

I think that they probably intended Binary Search for Subtask 1 and Ternary Search for 2, since log2(1000-2) is about 10, while log3(1000-2) is about 6.

But the ternary search solution would of course also pass for subtask 1.

yeah because log(999) is around 9 with base 2 which satisfies binary search condition for g1

I defaulted to binary search on G1, because I never had to implement ternary search(up until today w/G2).

shitty round for python users

exactly... i need to switch to c++ soon

why though? I'm doing python just fine

the pypy compiler gave tle on the same solution where python3.8 worked fine

I just checked out your D, and it's actually your fault that you got TLE.

You keep appending to construct a long string (e.g.

`ans+=s[i]`

), which is slow. Python's string is immutable, which means it will always take $$$O(n)$$$ time to construct a string (where $$$n$$$ is the length of the string). Your code needs $$$O(n^2)$$$ time to run due to this, which is obviously not okay.It's interesting that Python runs faster on this code, though. I guess that it has some optimization (like skipping construction when there's only one reference). But whatever optimization Python has, you should avoid appending a string.

yeah,thanks a lot

but what alternatives should i go for when i have a task like this?

String concatenation is a pretty basic technique -- try to google "build string in python" for in-depth tutorials. In sum, put string fragments into a list and do

`''.join(list_of_fragments)`

.Can someone tell why this is throwing compilation error ?

same solution passes now

I got the same issue, the checker says: "Can't compile file: Compilation process timed out.", so I guess the server was just so overloaded that it can't even compile the file lol.

I still don't understand how to solve B. I literally checked every possible case by hand. I don't know what's the right way to feel about this but I am furious.

Maybe u didn't consider when u win 1 round and tie the other (that happened to me)

No I did that, I did everything. I literally considered every possible way the numbers can be arranged relatively on a number line and this WA.

In your code in the if(bl==br) block, u ignore totally al, that part seems wrong to me.

that part was a last ditch attempt at doing whatever to get AC, the code I actually wrote must be my second last WA submission for B.

btw the case when al == bl && ar > br that u insta print 2 is wrong, cause u can have br ==bl and that makes the answer to be 4

Hmm now I get it, I though about this problem of bl and br being equal at the last moment, and as you can see I did something about it in the last moment in my last WA submission for B. But maybe due to crunch of time I left some cases.

Thanks I lot, now I feel good. I saw jiangly's solution anyway. To see what he did is to first observe that there is symmetry in the order of checking winning games. Say we flip a random card from Suneet and Slavic, then the other ones are fixed to be picked on the second round, moreover Those other two cards if picked first would produce the same final score. With this observation we can fix picking a1 first, then whatever I pick from b, I check whether my points are greater than the opponent. we do a1 with b1 and a1 with b2, get the result and multiply the answer with 2, because the case of a2 will conclude in symmetric final results.

Also, changed the line you pointed out and it's working. 274963920

i used next_perumutation() function of c++, to brute force all possible combinations and check how many times player wins

Why didn't authors announce

the 10 mins extendearlier???I was about to get E right, then I saw 30 seconds left and gave up. Later on I came back and saw the announcement that the round had been extended for 10 mins.

Trolled in B and with the infinity queue took 40 min to fix the error xDn't

How do you go on about solving F?

hint 1the median will be either 1 if number of ones are greater than zero in subsequence and zero other wise

hint 2u can count number of subseqences having x ones and y zeros number of them equal total number of zeros choose y * total number of ones choose x ( note x + y should equals k hence u need only to loop on one of them) and since the median equal 1 or 0 u only need the count on ur solution your only problem will be calculating ncr under mod which will involove modular inverse

hint 3for the modular inverse part herre is a nice problem u can try https://cses.fi/problemset/task/1079

For D, I got WA on test case 1, but it worked just fine in my local compiler and online compilers

Lost multiple submissions, also each submission took too long to compile. Had to change same logic in python and it got accepted.

Couldn't find the reason, can you guys spot it? https://mirror.codeforces.com/contest/1999/submission/274845944

It looks like there's a small mistake on your for loop statement:

The

`j--`

should be changed to`j++`

. Decreasing $$$j$$$ in the condition will result in an infinite loop or unexpected behavior since $$$j$$$ will never reach`s.size()`

. Correcting this to`j++`

should resolve the issue and give youAccepted.Why this code is giving TLE in problem E.1999E - Triple Operations

Spoilerthere is no restriction on l and r. So your code could iterate for 2e5 times for each testcase if all testcases have l=1 and r=2e5.

Is this really the reason? I have a similar submission that passes but loops through l -> r:

274871369

You are correct. I tried to hack your solution but looks like your solution is could also have been tle had you used unnecessary local variables inside loop, instead of directly reading values from SOL array like you are doing now.

You are looping from a to b for every test case. Imagine if there is 10000 test cases, each has a=1 and b=200000. Then you will TLE.

there is no limit over the sum of l or r over all tests. Therefore, iterating from l to r is not viable for big number of tests. Try with prefixsum

If you iterate in a to b, it would go upto 10^4*10^5 iterations in total. Raising TLE. There was no limit like sum of iterations being less than 2*10^5

Can I ask a question here?

In problem E, my code was giving me expected/correct output in my local machine, but is giving wrong output during codeforce's testing 274941437

Could any one tell why is that?

Btw, it was a great first experience to my first cp round :)

mathforces

Can someone explain how this is TLE:

https://mirror.codeforces.com/contest/1999/submission/274946145

let n be 2*10^5, where l and r are <=n

the while loop is log3n and the for loop is constant operations in O(N) time as well

You are looping from l to r for every test case. Imagine if there is 10000 test cases, each has a=1 and b=200000. Then you will TLE.

ur complexity is t*n_max, which will give TLE

Your time complexity is not NlogN. It's T*NlogN. Usually, you don't worry about it because it's stated N won't exceed 1e5 across all T for example, an important statement missing from this problem

But, 1≤t≤10^4 and 1≤l<r≤2⋅10^5. You iterate over [l, r] in every t. So it's n^2

Tanked 5 TLEs on E because I calculated the prefix array in the solve() function :( Also couldn't figure out why I got WA for G2 test 2

How did so many people solved D?

E was just algebra and prefix sums

I solved E greedy no algebra involved

yeah just precompute the logs, that's what tricked me to tle

D is completely based on a pretty common idea, that finding string as a substring in another string is successful iff it's successful greedily.

Hmm, quite easy div4, compare to the last 2 recent div4 rounds.

DuongForeverAlone orz. I've failed problem F since I don't know how to handle the modulo formula stuff. Else it's gonna be a blast for sure compared to recent div4 rounds

i used modular inverse and binominal coeff formula

Hi can you tell me what is wrong with my code in problem F it's run time error at first I wrote my own ncr and fast power but after stuck with the run time eror I copied one from the internet but still run time error there is a big mistake but I can't see it https://mirror.codeforces.com/contest/1999/submission/274946181 it would have been my first time to solve till F

You missed the new line after printing LOL.

still there is run time error the last case is giving different answer every time I compile it

The fact array is 200003 in length, but you iterate to 200009

`ll fact[200003];`

`i<200009`

also you are not printing new line in each test case

I just fixed them and got WA on test 3

what if K > N you didn't handle that

yeah thanks that was the problem

For modular issue (especially modular inverse), it has been one year since I implemented those things last time. After using the Modular class (actually I copy from tourist, but with some modifications), I could handle those modular operations with ease. I recommend to take a look at it.

sure, I think I will also copy python class from better players in the contest. Have to take the hit for the experience tho. (But not sure if this will be marked as plagiarism)

especially Div4G. But it does serve as a good intro to interactives.

B is the hardest easiest problem.

B is the hardest easiest problem

Best of luck everyone

The waiting queue is fucking long

In problem B, why don't we count the game starting with Suneet and Slavic separately?

it sames like every one can solve problem F, it's really hard for me

Any specific reason behind these very long wait queues in div3/4 contests? In my case today one submission took >15 minutes to resolve?

Maybe cuz there is generally more people participating in these lower divs

Too much participants, that's it.

Just got an observation for E:

[1, 3) -> all elements require 1 operations to become 0

[3, 9) -> all elements require 2 operations to become 0

[9, 27) -> all elements require 3 operations to become 0

[27, 81) -> all elements require 4 operations to become 0

[81, 81 * 3) -> all elements require 5 operations to become 0

and so on.

I think this could be optimal.

Yes u can see my solution I solve it using this observation

My wifi was cut off 40 mins after contest started. After that I tried whole time to enter the contest, I was getting verified but they were not entering me in the contest..

Now what? I will loss around 40 points for what? Inconvenience by Codeforces website?

Yes I tried the m2codeforces website too.

Palak e palak e sonkot

Ki je birokto lagse amar ... pura contest ee shudhu load ee hoise ... amake dhukainai

Enjoyed the round. Great problems. Couldnt solve F (cuz im bad with mathy type problems). +100 Delta letsgoo

for those who think that div — 4 is too easy for them. 1. find the 1000 consecutive integer where non of them are prime. 2. find the 1000 consecutive integer where exactly 10 of them are prime ENJOY.

Please explain why this doesn't work in problem B (says expected 4, found 0 on 101st test case): https://mirror.codeforces.com/contest/1999/submission/274897075

you're only considering when u win the 2 rounds, but it also can happen that u win 1 round and tie the other, u must include if(a>c && b==d)ans++ , and the others combinations of that.

Thanks!

how about this ? https://mirror.codeforces.com/contest/1999/submission/274813505

should work now![submission:275042431]

you can draw in one round and win in the second. which makes you win overall

Thanks!

can anyone explain the tle 274928746 for each testcase t it takes at most 10^5 iterations times log(10^5)base3

It will fail for the cases when one of the rounds are drawn. For eg.

1 10 2 3 2

Why does this give tle in test case 1 of E Submission

you got to precalculate those values using some prefix array..

why i got wa in 2nd test case.. 101st "wrong answer 101st numbers differ — expected: '4', found: '2'"

here's my solution: My B solution

can anyone explain, please???

mayb its because you are not considering the a==c and b==d and a==d and b==c etc. these cases

in these cases Suneet loses the round , right? but only considers those cases in which suneet wins i.e; (a>c && b>d),(a>d && b>c),(b>d && a>c),(b>c && a>d)

if it is a tie then it is not losing for suneet .. if he wins the other round he still wins the game ( it's in the problem statement but yeah this problem sucks :) )

Thank you guys for the great contest!

Couldn't figure out the scenario of 1 win with 1 draw in problem B and the precision error when use

`log`

Math function in problem E, but glad that I've up-solved them just now.After all I still enjoyed the contest!

interactive problems are SHIT

I think they are fun :)

Struggled solving F for over an hour with multiple submissions failing at testcase 16+ because of mod (made me sad especially after I seeing that G was just ternary search :( Otherways very nice contest

on paper this gives best answer but why it fails on test cases ?

``** **`

`~~~~~`

`int fun(ll x){`

`int count = 0;`

`while(x){`

`count++;`

`x = x/3;`

`}`

`return count;`

`}`

`~~~~~`** **`

void solve() {`** **`

ll l, r;`** **`

cin >> l >> r;`** **`

ll ans = 0;`** **`

ans += fun(3*l);`** **`

for(int i = l+1; i <= r; i++){`** **`

ans += fun(i);`** **`

}`** **`

cout << ans << endl;`** **`

}````Actually it should be ans+=2*fun(l) instead of ans+=fun(3*l) and also you got to precalculate those values using prefix array or else you will get tle ig

The only problem with the logic is when you increas ans by fun(3*l) instead of 2 * fun(l). For example if l = 9 we would want to reduce the 9 to 0 first. To do that we would have fun(9) = 3 operations but simultaneously another number would be multiplied by 3 two times. And to reduce it to its original value we would again need fun(9) = 3 operations. That's why ans has to be 2 * fun(l).

Also your code will hit TLE since you always recalculate fun(x). Instead of that you could precompute all of the needed values. I did it like this:

oh thanksss man

sooooo bad contest

submission 1 submission 2 CAN ANYONE PLEASE EXPLAIN WHY BOTH OF MY THIS SOLN GIVE WRONG ANS ON TEST 2 TODAYS DIV 4 B

its because you are not considering the cases where there could be a tie

thanks

how this solution have passed flamestorm

Exactly, my same code gives TLE

Can someone please tell me why my code for D failed? code: 274969671 I got this error: wrong answer Token parameter [name=ans_string] equals to "hjcjcng~", doesn't correspond to pattern "[a-z]{8}" (test case 163)

You need to replace all '?' With any other alphabet in [a-z]. Because as stated in the question-

Slavic is asked to change each "?" to a lowercase English letterI am getting

`Idleness limit exceeded`

, How can this be fixed?274961116

? a b — in response, we will measure the side lengths of an (a * b) rectangle

I think you implemented the binary search wrong, so that it doesn't halt. instead of setting l/r to x you need to set it to l+1 or r-1 and also instead of checking wether r-l > 1, you need to check wether l is smaller or equal to r.

Let me know if this works!

Remove this line

`#define endl "\n"`

Ah no, actually your query is wrong, you need to cout 2 values

lowkey B is the hardest problem here.

How some brute force solutions passes in problem E ?

can you share

Was a good round!

can you remove any codes using AI ? I know an account the code awritten using ai and this not fair!!

Good round, hopefully I can be a specialist.

Wow

Just virtual'd this contest, nice query limit at G2! It's so strict that even a minor suboptimal tactic resulted in a wrong answer, and for educational purposes I really endorsed it!

div5??hhhh

I haven't participated since the last year, and I was hoping to got this round rated... :( Isn't there any way to have this as a rated one. At the morning I was a contestant and now it seems to be a practice round. I don't know how many points do I deserve

System testing is running,in a few hours rating will be updated

well, system testing is taking forever and probably won't be done for a few more hours. So ratings probably updated tomorrow

G1 and G2 were quite interesting learned about Ternary search.

Waited 27mins in queue for G1 just to get compile error :)

Is there an additional penalty if I hack someone else's code multiple times and it doesn't work?

Hi Everyone

For Problem E ( E. Triple Operations) , I precomputed all the values using log_base_3 , but somehow it's giving incorrect result for 243 and 59049 , to pass the test cases i had to hard code the result , can anyone please help me here , why it's giving incorrect result.

For log values calculation i realized that precision values depend on the gcc compiler weird

Here is my submission — https://mirror.codeforces.com/contest/1999/submission/274923066

Check this and this comment.

As far as we're concerned, we only care about the integer floor of the log, and the numbers to get logarithm from isn't too huge, so we could actually bruteforce the log3 by continuously dividing the number by 3 until it reaches 0. TL;DR try to avoid floating point arithmetic as much as possible to escape precision issues.

I use continuously dividing method and get TLE

Precalculate your logs and call them when needed.

It was one of the best round I ever seen. Thank you !

Its been 16 hours from start of the contest now, does anyone know when system testing starts and when rating update will happen ?

hacking phase of 12 hrs was going on but ig its done now so we'll be updated in 2-3 hrs!

my can someone help me this 275053244

The issue is with the way you are making the final string (the usage of ind). Use this test case,

Your code will give incorrect solution to this. Try to see why.

1

abc?ef?h

abcdefgh

Try this.

Help!!! All of my race records have disappeared!!!! WHY!???

System testing is in progress, be patient.

Thanks

This might be the longest system testing ever,will go on for more than 10+ hrs.

good contest:)

queueforces

bruh system testing is

How much longer do we need to wait for ratings update? And how do y'all get to know when system testings are going on?

go to the main contest page, where the problems are listed and on the right it will show the system testing progress.

looks like it will take another 1-2 hours, ratings will probably take 12-24 hours after that.

System testing is taking forever. Waiting for results for 12hrs.

Yeah fr! I like codechef's live rating. It would be great if something like that was introduced here(Ik we got open hacks, recalculation and all, but what i am suggesting is provisional rating which could fluctuate...)

you can use carrot extension :)

it's not accurate

Whats this? I am new in codeforces so i would appreciate if you could help me!

it is an extension which predicts your rating change before actual change in rating. It gives you rough idea about how much your rating will change.