Wazzup Codeforcers!
sum, satyam343, and I are extremely ecstatic to invite you to Codeforces Round 965 (Div. 2) on Aug/10/2024 17:35 (Moscow time). You will be given 5 problems and 2 hours to solve them. 1 problem will have subtasks. This round will be rated for all participants with rating below 2100. We spent the most time cooking up this round than any other round, so it means a lot if you will participate.
We would like to orz the following individuals for making the contest possible:
Our coordinatorz satyam343 for his gracious coordination and donation of his own problems to this contest.
Our testuwuers: Benq, omeganot, maxwellzen, 244mhq, null_awe, Dominater069, A_G, Yam, IceKnight1093, Phi-001, CSQ31, fishy15, Java, kingmessi, Pols_Agyi_Pols, harsh__h, awesomeguy856, tyr0Whiz, andrewtam, oursaco, 18o3, lethan3, Stefan2417, milind0110, willy108, amsraman, MridulAhi, AryRDW, h2rsh, page_fault, IceWolf898, US3RN4M3, callmepandey, jay_jayjay, flight, xug, Qualified, Sacharlemagne, chromate00, ntarsis30, redpanda, Faizal, windreaper, yash_9a3b, Prady, Non-origination, waidenf, ETL, oddvalue, and Rahuldeb5.
Alexdat2000 for translating the statements to Russian.
MikeMirzayanov for developing Codeforces and Polygon (mentioning this so I don't lose 1000 social credits).
Score Distribution: $$$500 - 750 - 1250 - 1500 - (1750 + 1750)$$$
Wazzup guys! I encourage you to participate in CerealCodes for their Summer 2024 Contest.
CerealCodes is an organization based in the United States dedicated to running high quality competitive programming contests. We were responsible for Codeforces Round 887 (Div. 1), and you can check out our previous contest here and here.
We are holding our second contest on August 17th-18th with over $1k in prizes for pre-college students and some great raffles for everyone! You are able to make teams up to three. If you're interested, be sure to join our discord server and check out the logistics for the contest here.
Disclaimer: This round is not affiliated with CerealCodes.
cereauwucodes
I knew the CerealCodes round was going to be good once I saw cry there!
I will be cry ing because I can't participate :/
I will be Laugh ing because you can't participate :)
I solved around 7-8 800 rating problems and still couldn't solve a single problem in todays contest. Any tips on improving it or some prerequisite i don't know? I know a bit of STL but don't know how much is required. Please help
this is because the round is much more difficult than usual. number of solutions on c should be way higher. like that kind of a gap occurs at c-d problems most of the times, not on b-c.
just try learing some simple logic, i recommend you participate in div.4 or div.3, those problems are much more beginner friendly
I would say the first problem today is maybe slightly harder than the first problem normally is.
I would recommend just solving some more low level problems, you'll get the hang of it eventually.
This was my approach for problem A today.
If the points have to be centered on xc, yc then our points have to be symmetric in some way. An easy way to do this is just to put all our points in a line, like this:
. . . c . . .
If we have an odd number of points, then we should put a point in center, and then put half of the other points above it and half the points below it.
If we have an even number of points, we do the same thing but leave the center blank.
There's a bunch of ways to calculate where the other points go.
this will be a great round
this will not be a great round
this will not be a great round
kek
bad round
As a first-time tester, I am proud to finally be able to write an "as a tester..." comment :)
As a tester.
As a tester,
🦧
🙈 🙉 🙊 🦍 🦧 🙈 🙈 🦍 🙊 🙊 🙊 🐒 🐒
As a tester, I cried because of how beautiful the problems are
Aa a participant, I will cry because of how beautiful the problems are
As a participant, I cried because of the difficulty gap between B and C.
As a tester, I will take the round for infinite delta.
I think I'm the first non-tester to send a messages!!! Can't wait for another cry round!!!
As a participant, I feel like the tasks will be very unpredictable.
skill issue
what does having subtasks mean ? Will we get partial points for solving the subtasks? I am new to this concept, can anyone explain please
its essentially 2 identical problems, except for some constraint or some important detail being changed, so that the 2nd version is harder than the first. sometimes you can just solve the harder version and submit the same code for both of the versions, but there are exceptions to that, for example this and this,
cry orz
Good luck to everyone!
P.S. It seemed that the author wrote"Russian"wrongly,instead,he wrote"russian",the first letter was a lowercase letter.
This contest is the end of an era of Contest IDs with a 4-digit number beginning with 1. On to the 2xxx’s for IDs
It's 1998 not 2000. You can copy the contest link and check if it is.
This is the last contest that starts with 1xxx
Sorry, I misunderstood.
since from when were we getting 1xxx IDs?
Did anyone note "coordinatORZ"?
also testuwuer
The round feels more solid with cry and sum as problem setters! :)
how Grandmaster become cyan over 1 year? I'm genuinely curious. I'm talking about the coordinator of this round satyam343. is this level of degeneration really something that could happen or just troll?
look at his recent contests, seems like troll
He is just solving the hard questions or the questions he wants to solve. He has no intention of increasing or maintaining his rating
Monkey doesn't have any pants
WTF THATS ME
Beware of identity theft!
You too bro
You don't have to tell me :(
Did satyam343 sell his account or what
the best birthday present ever :"]
i will reach gm
hypeskynick orz
Although the number of the round is 1998,it is the last contest with the id like "1xxx`.
As an expert participant, I hope to reach back to CM.
same, although somewhat unrealistic
more contest noice
milind0110 sir Orz
Hope to reach Pupil 3rd time
first unrated div 2 for me :D
Not gonna lie your last div3 was probably the best div3 I have ever given. Decode and Bomb, both were beautiful problems.
what is wazzup??
Good luck and have fun! :)
potato monkey
Score distribution?
Hopefully I get to add some blue to the green of my handle.
damn
Hoping to become cyan after the contest.
Hoping for this to be my best round in 2024 :prayge:
Excited for the contest. yeeeeee
i hope one day i can proudly stand in the "Our testuwuers: " line owo
2 Min silence for those who judged the coordinator on his current rating
I'd be thrilled if i reach cyan after this round.
Awesome recent performance bro. I also hope to reach cyan this round.
Wazzup
18o3 and satyam343 Orz
Just dont make us cry :')
anyone miss my comments?
Asuna_Yuuki
your pfp is too cursed
why? :(
Good luck, hope its not math forces again
Good luck for everyone <3
what is the point distribution?
Good luck everyone !!!
is it only me or codeforces is quite lagging recently
I see satyam343. I'm shaking. Please no counting maths problems this time. I hate those. Please satyam343 We believe in u.
I read binary strings and permutations, I stayed out. Glad I did. Indian authors and their love for maths, binary strings, and permutations, etc.
I hope you don't mind me using this comment in problem C. I just found it funny :p
haha, feel free to use it.
As a participant I am excited .
Any specific reason for the contest to be of 3 hours? Also, eagerly waiting for the point distribution to be updated.
its 2 hours
hope i can solve at least 4 problem XD XD XD
Counting is not fun.
Hoping for delta 200++ round. been some time...
May you good luck!
Thanks !
first two problems, solved in 5 minutes.
C problem solved in 1 hour 53 minutes. .
3 times understood the problem completely wrong. Feeling so stupid. should have read the the test cases first.
how did u do C ?
Hint 1 :
We need to go greedy. If we apply 'k' addition, we will apply it on one single element. To deduce this, you can try few test cases on pen-paper. find the current median, try to delete elements from left of the median, or right of the median. There also, we need to check if the array is EVEN or ODD size array. So many IF-ELSE :| . you will always find this EXCEPT one edge case ( below described)
Hint 2 : Edge case handling. 3 4 1 1 100 1 1 1
In above input, it is best to pick 100 and delete it, and then take median of rest of the array. Sort the values, and pick the last value, and then see, what is the best median you can get from remaining N-1 elements. For that I used binary search.
Now, we have to take the MAX() value from HINT-1 approach , and edge-case result.
alright
As a contestant want to be Master, i wish i can be Master in this round
cry orz
but what score distribution it is? I think, correct me if I'm wrong, usually score's are almost equal to it's difficulty, so I'm supposed to solve till E1(it's almost full)? Even if it's not, isn't SD unusual?
There is no such rule or guideline that the score should be equal to estimated problem rating. It's just that they tend to be similar, but they don't necessarily need to be like that. Score distribution tends to be more exponential than problem rating, and therefore we sometimes have problems of 250 points and 6000 points depending on relative difficulty difference of problems, which is pretty far from their problem rating. Also in Div. 1/2 separated rounds 1A is usually scored 500 points but they're as hard as *1500-rated problems.
thembululquaUwU
interesting score distribution；GL&HF
aaj speedforces hoga kya bc :D
As a tester, all the problems are very good and no problem will make you cry
At first glance the monkey looks like its showing middle fingers!
I don't know why but looking at this monkey is so relaxing
is it still relaxing after the contest ? The monkey was the silence before the storm.
I thought this is a LeetCode contest after looking at these problem titles
I couldn't think of a good title for this problem, so I decided to learn from LeetCode. — Sun Tzu, The Art of War
its well known leetcode is the best competitive programming site, we should all learn from it
its well known CODEFORCES is the best competitive programming site. We are learning from it. xD
If it ain't broke, don't fix it. -Sun Tzu, The Art of War
UnbalancedForces!
unbalancedforces!
nice 2000 rating third lmao
what is this problem balancing
mathforces , worst contest
Did they accidentally give us a Div1 instead of Div2.
not really only Div2C was off in difficulty. Acted more like a D.
there goes my rating. Got outplayed in problem C so hard I don't even want to read D and E anymore
speedforces!
Horrible coordination, score dist. is shit.
What a drraaag...
problem rating: 800 800 2000 .... so on. Just let me reach pupil pls..
800, 900, 1800, 2000, 2100, 2500 if I were to estimate.
as a Newbie, Pupil, Specialist and new experts the contest duration was 20 minutes or less
Yeah A+B took me 5 mins, C and D took almost an hour each.
-_-
If you can't make a div 2 round just dont.
If you can't come up with your actual id then don't comment :)
unbalanced-forces, contest should be standard div 2
i am not giving the contest currently but this guy is streaming and giving out the solution for the contest
can you do something about this
i can rarely solve 3rd in div 2 this mf is giving them away
mf madarchod https://www.youtube.com/watch?v=dDZyHLJVHaM
Well the most you can do is not advertise cheating telegram groups.
Is it just me or there is a problem with same solution to problem B on Codeforces? Also,you liked your social credits joke?Now you have earned your negative credit from me.Hope you liked it.
bad contest problem c was too hard for normal div 2
I feel like it is okay, but requires a lot of time to implement, if one doesn't know certain tricks. I'd like to have a full day on it, breaks included, not just 2 hours ;D ...and still not sure my idea would work, maybe this is all just a ramble of a low-skill.
Of course, given the amount of people who solved, 1250 on rating distribution doesn't make any sense. Looking forward to the editorial...
if you can't offer normal div2 problems, please don't do it
I personally didn't like their Div 3 either. "Counting is fun", huh. But math guys will argue.
DIV2 C ???
more like Div2D
Contest too hard, me sed. Back to newbie here I go.
I've just become Specialist last Div. 4 Round. Again, I'll be Pupil, or even Newbie.
What Div.2 C??? Wish not this again.
Yes. That's for sure.
One's demise is another one's triumph. Someone would have the rating. Maybe one specialist guy, who solved A and B fast enough (not me though, 0:11 A). Let's cheer for them this time.
When participants like neal , aryanc403 got stuck on 3rd problem How am I going to get motivation to solve that .
don't look at AC-count and standings, just solve problems in the order they are given. as easy as that
All of the logic was correct in my 0:13 submission, I just had a nasty bug that I didn't manage to fix for another hour :')
for me, I had to use binary search type techniques on C to get it down to correct.
All of the logic was correct in my 0:35 submission, I just had a nasty bug that I didn't manage to fix until the end of contest :')
Seeing that you hadn't solved problem C while my solution for problem B got accepted, I knew I should just give up
Really only 1250 points for problem C?? should be 1500 considering difficulty!
Too much harder than Div.2 before!
stupid contest
Man the C was so hard it took my soul with it .
Gonna need a 3 mo break from cp after this
E1 is just B(altic)OI 2022 islands on array instead of tree.
Or a slight change to https://www.facebook.com/codingcompetitions/hacker-cup/2023/final-round/problems/C.
wtf is that C?
thats why i am afraid of satyam343
problem C score should be at least 1750 imo
Can someone please explain, why in in 4th sample Bessi loses if she starts at 2nd and 3rd islands?
Elsie goes 1 to3 and then 3 to 8
But Bessi goes first????
nvm bro, elsie goes 1 to 6 directly. Problem C has fucked my brain
Bessi can get from 3 to 8 in the 1st turn
bessie cant use these bridges tho, she can travel 1->2 , 2->3 , 3->4 and so on
I didn't read the statement properly :(
:( Contest was a proper nightmare
Median again.
this problem C crush my soul, I can solve it if b was all 1. But not like this
Came back after skimming others thoughts/code. splitting array a into b=0 and b=1 only actually help... Well, need to take a hit and learn tho
why this approach (https://mirror.codeforces.com/contest/1998/submission/275607879) for problem A is wrong, any counter test cases?
the points you printed out aren't distinct
How? Any test cases?
Try this test case
0 0 2
Thanks! got it
:(
Why do I get WA4 in D? 275609322
You didn't add edges between islands i to i+1 in the graph.
Nooo that's how I WAed too :(
Why do I need them? Cow cannot be overtaken by this edges. Can you provide testcase please?
It affects the time array calculation.
Ooooh, I see. Okay, time to kill myself. Thank you!
Lmao this is how I feel too
May be, i am noob or C is a bad problem xD
I'd say the rating distribution was not okay, but also yeah, we are noobs.
satyam343 bro played with the emotions of his biggest fan lol!
https://qoj.ac/problem/3511
Problem E1, E2 was on JOISC.
what's this site? qoj? thank you. (there is no intro in their website)
One more median problem and I am killing myself :D
С sucks. Its true rating seems to be pretty higher than it's stated. Can't imagine what was on contest creators' mind when making this distribution
ok yay you did it hope you didnt wa on test 2Scary motivation.
C solution:
Consider two cases:
I) Greedily choose the largest number that has its $$$b = 1$$$ and spend all your $$$k$$$ on it.
II) Binary search on the largest $$$\operatorname{median}(a)$$$ you can make by the given $$$k$$$, then calculate the answer for this case.
The answer of the problem would be the maximus answer of two cases described above.
In test case 4: how answer : 13
all operations go into 4, and then median is 5 after you remove the 8, 8+5=13
Spend all $$$k$$$ on that $$$4$$$, so it becomes $$$8$$$. Then take that $$$8$$$ and new median which is 5. So the answer would be $$$8 + 5 = 13$$$.
I realized this, but i couldnt implement finding the larget median, how do you do that?
can you provide your solution ?
Yeah but how exactly do you apply binary search in the 2nd case? Arent there too many posibilites to consider?
in II in case of odd length our median is (sz+1)/2-1 right ?
i hate your biggest fan.
why this not working for A
Maybe if k%2==0---->if k%2==1
if xc,yc=0,0 and k is even you will print two times the point (0,0)
nice observation man now i got the answer
it Got Accepted,so that was the only case my code failed
5 4
7 5 2 5 4
0 0 1 0 1
13
???
Why in problem C 4th example it's 13 ?
You spent all 4 op on 4 then you get: 2 5 5 7 8. The answer=8+5=13
thanks. you are right
I just realized that I was solving a different problem.
soon you will realise that Gojo in your DP isn't real :)
Apply operation on the last element 4th times it becomes 8. Removing last element the median will be 5. So 5 + 8 = 13
If you use all your operations on a[4] (initally 4), it will become 8.
The rest of the array is [7, 5, 2, 5]. Median is 5. So, answer is at least 13.
pick 4 and spend k = 4 on it. The median is 5 (2, 5, 5, 7). So answer is 4 + 4 + 5 = 13
After this contest, I will never look at score distribution again.
Nice, well-balanced contest. Also felt like "real" competitive programming (too many contests feel like math these days).
Well maybe B-C gap is a bit too large but C-D-E1-E2 is well-balanced imho
Oh my God, I only have 15 minutes to do problem E1, and because I was in such a rush, I didn't realize that the complexity of my code is $$$O(n*log^3n)$$$. Maybe if I convert the segment tree to a sparse table, I'll get AC.
$$$O(n * log^2n * log \max)$$$ passes with iterative segment tree
Maybe my implementation is bad because I wrote around 100 lines in a very rushed time (< 10mins). Unlucky for me this time.
I also had the same complexity and did not realize it at first. I ended up adding a bunch of heuristics and it passed pretests in 2 seconds (out of 4), still may fail systests though. I am not sure if those heuristics improved asymptotics. I kept segment tree.
I didn't even have time to check the verdict of my submission because the time was up :<
worst contest i ever participated in. i acidentally sent my solution where arrays were too small and i got RTE on test 5 and i placed 6000 instead of 3000 because of that. its a skill issue, but still crazy
Messed up with output on A, found it's failed on 1 pretest only after ten minutes :D Kinda feel the same...
If this is the level at which C is going to come i don't think i will ever reach expert
Almost submitted C, found the error in the last minute but had 5 secs left to submit..
I was ready to solve C before the 1 hour mark, maybe even solve D and get back to expert. Let's just say I was too naive hahaha
as someone who did that, it would place you closer to CM in ratings.
Oh wow, yeah... this Div2 is so broken, some past few contests I solved A. B, C too slowly and couldn't get D, my final placement for those contests is lower than this one where I only solved A and B lmao. Codeforces contests can be really random sometimes...
can't do C :(
Has anyone observed in the last 20 min, that accepted submission in C increased by 50% from 1K to 2K?
because it's leaked on youtube.
Felt like this div2 had 2 As and 4Es....
2 Bs and 4Es rather.
when is rating roll back?
Yaaaay I solved C lol! I'm so happy!
Just choose one of two options:
max(ans1, ans2) is the answer.
Your text to link here... I used the exact same method as you, but why does my answer work perfectly on my own compiler, yet I keep getting a runtime error (RE) on the judging machine?
my ac submission I just changed a "vector" into "deque" and got an AC! What a pity!
Happy to solve C, get the logic in 20 min but take an hour to complete code.
Interesting round. The solutions end up being so simple you almost feel ashamed for spending so much time on the problem lol.
Also, C might be more difficult than what I've seen in the previous rounds.
What were all these testers doing?
Making Fun of us.... ok yay you did it hope you didnt wa on test 2 (4 test cases)
C was a long implementation, atleast for the approach that I thought T_T
imho C shouldn't be this long implementation based problem, but other than that cool round, infact I love how C boils down to a simple solution
terrible contest, i dont really see your balance setting on Problem C. Maybe you need more preparation on testing your problem. BIG DISAPPOINTMENT
I finished C at the last minute literally, so I hardly had time to check my answers in detail. I hope it will pass the system tests :I
use 15 minutes to think about C and use 2 hours to code and debug it
Can anyone tell how binary search can be used to find the max median in C?
Possibly use the same idea as the problem D of the last contest.
OK... so here is the my idea for the whole C...
1) Sort the array $$$a$$$(Try binding with $$$b$$$ to make coding easier);
2) Assume the index of median of $$$a$$$ is $$$i_{mid}$$$, the median of $$$a$$$ is $$$median(a)=MED(a)$$$.
When no operation can be done($$$k=0$$$), the answer should be $$$max(a)+MED(a)$$$;This can be shown that:
2a) Choose the last element, we get the score $$$p_{max}=max(a)+MED(a)$$$;
2b) At index $$$i<=i_{mid}$$$,we select $$$a_i<=MED(a)$$$ and delete it , the median may change to the $$$a_{i_{mid+1}}$$$. But after all the answer will be $$$a_i+a_{i_{mid}+1}$$$. Since $$$a_i<=MED(a)$$$ and $$$a_{i_{mid+1}}<=max(a)$$$, This is not the answer;
2c) At index $$$i>=i_{mid}$$$, deletion won't change $$$MED(a)$$$, so $$$p_i=a_i+MED<=p_{max}$$$;
3) Then we are allowed to do operation. Obviously the answer will just get larger. Since the answer is contributed by two parts: one element and one median, the intuition is that:
3a) we increase the element;
3b) we increae the median;
3c) we increase both the element and median;
4) Assume after optimal operation, the final array become $$$a^\prime$$$.Then we find that:
4a) 3c) will never be the optimal solution.(Little hard to find tho...). From $$$p_{max}=max(a^\prime)+MED(a^\prime)$$$, we know that if we increase the $$$max(a^\prime)$$$ by 1, $$$p_{max}$$$ will also increase by 1. At the same time there is no assurance that increase some element in the array $$$a$$$ will change $$$MED$$$ (if changed, increase at most 1). Just to make it clear that increase the $$$max(a^\prime)$$$ is more effective.
4b) So if we only change the $$$max(a^\prime)$$$, we bet all the operation on it. This can be done by increase one available element in $$$a$$$ to $$$a+k$$$ and calculate the answer with $$$O(n)$$$ or even $$$O(1)$$$;
4c) if we only change $$$MED$$$, $$$max(a^\prime)=max(a)$$$ will be fixed and won't change ever.
Then all we need to do is to find the maximum reachable $$$MED$$$ in the $$$n-1$$$ size $$$a[:-1]$$$ within $$$k$$$ operations.
One possible solution is that Binary search the $$$MED$$$ through this way:
Given the target $$$MED$$$, we iter through the $$$n-1$$$ elements and count all the element smaller than $$$MED$$$ while recording the operation needed if the element can be changed to $$$MED$$$. After the iteration if we find there are more than $$$int(n/2)$$$ elements smaller than $$$MED$$$, then we should use the operation to decrease the number until less than $$$int(n/2)$$$.
Obviously we should change the largest element as possible to reduce the operation needed.
Finally if $$$op>k$$$ or $$$cnt$$$ can't be reduced to $$$int(n/2)$$$, $$$MED$$$ is unreachable. Otherwise reachable.
Wish my explaination could help you. If my solution is wrong just hack it..
I see. Thats pretty helpful. Thanks!
I don't understand why my first solution do not pass. Maybe problem with C#.
Whoever created C deserves capital punishment
Didn't solve C, too difficult for me (`o`)=3
Please let us know if an author is indian. I will skip contests which have indian authors. PS : I'm Not tryna be racist, but indian authors like too much maths and observational trick problems.
isn't it the case with russian and chinese authors too?
no
Satyam is only indian author, and i dont believe he has a single problem in the contest
my bad. I apologize.
It's clearly written--
"Our coordinatorz satyam343 for his gracious coordination and donation of his own problems to this contest."
so we're in copper
finally get true purpose of the author posting ape pic
Most imbalanced and disappointing round ever...
Any idea for Problem — C
key observation:
if b[i] = 1 then there is no difference between in action (increasing value itself vs increasing median) so we take a[i] + k + (median after remove a[i])
if b[i] = 0 then we need to take a[i] + (median after remove a[i] then use k operations to maximize the median) and it can be shown in case of b[i] = 0 we only need to consider one case where a[i] is max
Thanks for the good observation, even so after this we have to solve median problem by using k to divide accumulation result of binary search on (a[i] having b[i]==1) to have the final answer though
cool round FST on A :)
same and i dont even understand how
It's because when you find out the last point, it may not be distinct from the (i,i) you found earlier in the k-1 iterations.
yah, thanks
why does that actually happen? I don't see any problem with your sol
k * x — sum can lie in between 1 and k — 1
I don't think so!
What?
I struggled so much on B when all people did it in less than 5 minutes it took 30 minutes how are you guys able to guess this thing in a seconds ? can you tell me what did you think when reading the problem
Wrote a brute force solution and found a pattern.
that's what I did but no one did this I think
well if you just rotate it once, it works. kinda just intuitive i guess
My observation is that changing one of the pair can make its sums different, then consider what about shift more numbers.
FST on A, whyyyy?
what is fst?
fail system test
i think i can understand the meaning of cry now lol
Submitted C in last few seconds,I have even no time to check it:(
WTF literally FST on A
now i can understand the meaning of cry
Cry made me cry today
i got FST on A, this was my second div 2 contest and i was so happy i solved 2 this time :\ (i solved only 1 last time) and btw why was there such a huge difficulty gap between B and C? damn
Hi, can somebody please explain why my submission gets WA? 275619036
When I change the line
to
I get accepted, but I don't see why that would cause problems? (I define int as long long)
I think the variable
usedto be overflowing.Omg, you're right. Thanks :{
a better way to get a hi value without any overflow problems. create a function $$$ f(x) $$$ which return true if x is a valid option in binary search or not. (you cannot create it if you want but it looks cooler and nicer). then do this
This ensures we get a valid hi value without running into overflows
cry definately made me cry lol....Didn't expected to get back to pupil after grinding 1600 rated problems rigorously for past one month.....
Dont worry. In Vedant We Trust!
Why was it that after being hacked, the correct code in front of me was skipped
This code
This code of mine was wrong so I resubmitted because this code fails for: 1 10 0 20
Don't know how this code later got accepted. Please check into this.
The number of correct submissions going from ~1000 to 2000+ in the last 20 minutes totally not suspicious?
Majority of submissions have this code, most likely copied off youtube or telegram. 275628589
yeah and some think they're slick and have changed it a bit, like this guy lt_gen_Dp_Pandey
https://mirror.codeforces.com/contest/1998/submission/275628589
wait nvm it's the same guy, what a coincidence. That's ok, I've found a new guy who thinks he's slick. This guy: butler66
https://mirror.codeforces.com/contest/1998/submission/275623856
THANK YOU
The amount of correct submissions usually looks like a logistic curve anyways, so it's kind of expected?
True, but 50% correct submissions in the last 20 minutes is a bit too much.
That's also true, but I personally find multiple similar submissions (all copied solutions will fall into a couple of groups anyway) way more convincing than the pure amount of AC solutions, which might differ a lot based on a lot of factors.
hard C.
Do we have editorial for this?
Aside from the difficult C, I think the description for E was also a little too complicated. I mean, this kind of problem would be much more understandable if the legend has a more reasonable story behind it, rather than using all the mathematical formulas to be extremely formal.
For example, this problem can be easily modeled as each $$$a_i$$$ denoting a power of the $$$i$$$-th character and it can absorb either the $$$i-1$$$-th or the $$$i+1$$$-th character's power if the $$$i$$$-th one has greater or equal power. Then the question is to simply find all the ones that can possibly survive to the end. In this way it's easy to reason why this process has to happen, and is much more simple than explaining this process with an array and a set.
The description of E is what makes it the last problem lol.
275593102 Why does it fail? (Problem A)
Because your code is printing the same point again for some testcase. The goal is to print k distinct points.
I got destroyed by this contest. Still I must admit that problems were interesting.Thank you for the round.
I really hate it when it gives pretests passed but wrong answer later,just demolished my rank.
"All wars is deception" Sun Tzu, The Art of War
and ofc... "Whatever you do, never reveal all your secrets in a Youtube video.. you fool!" Sun Tzu, The Art of War
Technoblade reference
That C was something...
So many W5 in A.
A had very weak pretests (my code had some flawsobviously and pretests just didn't include x=y cases where my code failed) Anyways I have learnt not to trust on pretests (and sample test cases obviously XD)
If i registered for a contest, but unable to participate in that, Will it affect my rating ?
No, it won't.
i think it is no affecting in
Can someone help me why 275686807 is failing on test 15 ? I'm trying to remove each element. If the removed element corresponds to b[i] = 1 then adding k to the removed element. And if b[i] is 0 at that index then binary searching on the median to maximize it with k.
How beautiful the problems are.
Hi[user:cry],
I got plaged in this round at problem C. I don't know how. I use to give Claude AI my codes to rewrite it and make it not readable but keep the logic same. I use to do this after my solution was hacked by someone a while ago. My friend suggested to make the code less readable. But I can't be plaged for that. Please look closely at this code.
I was asked to post comment here to help me with my plag. Can someone please help me with this? I have been giving contest from this Id to put the rating on my resume, but in the notification it was mentioned that I may get blcoked for this plag. If this happens then I won't be able to give contests again before my placements and it will not be fair.
I have already put this Id in the application form of several important companies and if my offer got revoked just because of this mismatch then my career will be adversely affected.
Dear Codeforces Team,
I hope this message finds you well. I'm writing with a heavy heart regarding the recent issue flagged for my solution to problem 1998D. The notification states:
*"Your solution 275630271 for the problem 1998D significantly coincides with solutions [user:razz_11]razz_11/275627442, his submission
EclipseWraith/275630271."my submission
I want to clarify that the solution I submitted was entirely my own work, and I have no connection whatsoever with the other participants involved.
With a contest involving around 30,000 participants, isn’t it plausible that solutions with similar logic might emerge, especially when we all are tackling the same problem? It’s disheartening to be penalized for something that’s beyond my control. My code is not even close to the ones it’s being compared to, yet I’m facing the possibility of penalties that could significantly affect my time, efforts, and rating.
I understand the importance of maintaining fairness and integrity in these competitions, but I assure you that my intentions were honest, and I have always followed the rules. It’s upsetting to see my hard work and dedication being questioned due to circumstances that I didn’t create or contribute to.
I request you to please reconsider the decision and review my submission carefully. I’m confident that you will find no malintent on my part. This issue not only affects my rating but also demotivates me from participating in future contests.
MikeMirzayanov,Vladosiya, I know you might receive many such messages, but this truly affects participants like me who put in a lot of time and effort to compete. If this issue cannot be rectified, it may lead to many users, including myself, considering a shift to other competitive programming platforms where such occurrences are handled with more nuance and fairness.
Thank you for your understanding.
satyam343 sum cry
Could you guys consider reviewing my C solution once again please? While I saw the similarities and won't deny their existence, you can check my unofficial submissions to see the Binary Search on answer codes I have been writing before which also match the syntax used in that particular program. The only difference is using auto instead of my normal loop (which I had used a day before on some spoj and leetcode problems). Rest is just similar logic for binary search because that's how I have been writing binary search till now.
I have been accused for similar submission in this one particular problem before too however that's not the actual case since it's just the nature of the problem that gave similarities.
The template used is unique to me as well. Also, I have never got any skipped solution before this (never cheated before) and you can see my rating graph also looks normal with certain ups and downs unlike those of cheaters who go straight up. There have been contests where I have solved just 1 problem due to poor temperament as well which wouldn't be the case if I cheated my way through here. I am aware of the fact that past records don't really prove that a person can't cheat in future but they might help you confirm if my growth is organic. I'd request you to review it again in an unbiased way (Not calling you biased but from what I have observed people on this platform jump to conclusion too quick once someone is accused, not realising the difference between accused and convict).
I am also ready if you decide to get my account banned if genuinely found guilty. Another thing I would like to bring to your notice is that solution got a lot of similar submissions. Now while this might seem an evidence for the counter, I would want you guys to notice that only 2000 people solved it in the contest. So was it like 60-70% people cheated in that? And if it leaked at mass scale then why did it have just 2000 submissions while other leaked codes have 10k+? Again not a statement just an open ended question.
Dear Admin,
I have received the notification regarding the significant similarity between my solution and those of other participants for problem 1998C. I would like to address this issue as follows:
Independent Work: I developed my solution independently during the contest without any external assistance. I did not engage in any form of collaboration, nor did I share my code on any public or private platforms before or during the contest.
Common Approach: The approach I used in my solution, which involves binary search and sorting to find the optimal value, is a well-known technique for such problems. It is possible that other participants arrived at a similar approach independently, leading to the resemblance in our code.
Commitment to Fair Play: I am fully committed to adhering to the rules and spirit of fair play in competitive programming. If there has been any inadvertent error on my part, I sincerely apologize and am willing to cooperate fully with any investigation.
Request for Review: I kindly request that you review the situation thoroughly. If there is any evidence that points to a common source or method that might have led to this coincidence, I would appreciate knowing the details so that I can understand how this occurred.
Thank you for your attention to this matter. I am ready to provide any additional information or clarification if needed.