Hello, Codeforces!
Daniel_yuan, waaitg, smg23333 and I are glad to invite you to Codeforces Round 706 (Div. 1) and Codeforces Round 706 (Div. 2), which will take place on Mar/10/2021 15:05 (Moscow time). Note the unusual time of the round. In both divisions, you will be given 6 problems and 2 hours to solve them all.
We would like to thank:
- isaf27 for the great coordination and discussion.
- KAN for the great help with round preparation.
- Wolam for
all his rejected problems anddiscussing the problems with us. - tiger0132, EmptySoulist, CYJian, parallelist, Sunward_z and ODT for testing the problems in advance and sharing their ideas.
- dXqwq, LTb, rui_er, CSP_Sept, Qiulyqwq, mac, dapingguo8, mazihang2022, Ashishgup, aajisaka, i_wyxkk_ak, mnaeraxr, Mitsukasa_Ayase, Oak_limy, Iidaqi, zscoder, Lovely_Ran, lgswdn, feecIe6418, orzdevinwang, happydef, Kewth, Widowmaker, star_xingchen_c, 3.141592653, Aaeria and 4c5948 for testing the round and their invaluable feedbacks.
- MikeMirzayanov for amazing platform Codeforces and Polygon.
Score distribution will be announced before the round.
Hope you all gain positive ratings $$$\Delta$$$ in this round!
UPD1: Score distribution is
Div. 2: $$$500-1000-1500-2000-2500-3000$$$
Div. 1: $$$500-1000-1500-2000-2500-3250$$$
UPD2: Editorial
UPD3: Congratulations to the winners:
Div 1:
Div 2:
As a problem setter, I set some problems.
As a problem setter, I set some problems.
Tao God, eternal God! fkami, my superhero!
As a tester, the statements are short and pretests are strong and give me contribution.
As a contestant, I will take back my up-vote, if the tests turn out to be weak.
You can't do that.
I can,by down-voting from an alt account.
how does one become tester?
As a contestant, this claim was incorrect.
pretests are strong!
codeforces × FSTForces √ :(
I love this round and wish I could participate in this nice round (but sadly as a tester I can't, but can I get some contribution?) XD
Good Luck!
...
As a problem setter, I want some contribution, too. XD
"In the upcoming round, you can use only Kotlin." is this notification for this round?
Apparently no. That's the notification for Kotlin Heroes: Episode 6. This round is a normal Codeforces round in which C++, Java, Python, etc. can be used.
As a contestant, I will solve some problems. :-)
As a contestant, I will try to solve more problems than create?..
Sure.. you can but for this, you have to solve problem sets for past contests. :)
I just meant I don't want to be additional problem for the contest creators :D
As a contestant, i will try to solve all problems:)
BEST OF LUCK BRO. ;)
Okay, I am a bit serious now, how to be a tester and what are the perks of being a tester ?
It is NOT funny anymore, stop repeating this stupid flat joke 100th time in a row after every announcement.
Why still no rating changes for div2? Over 16 hours from the end of the contest passed and still nothing
As a tester,this round is really nice,statements are short and clear and problems are interesting.
Wish you can enjoy the problems and get high rating!
Don't forget to upvote me XD
upd:Imakf why you steal the first comment >_<
As a tester, the statements are short and pretests are strong and give me contribution XD
Not so strong pretests apparently :/
Why doesn't B have multiple testcases (like A and C have) to check for edge cases in the pretests?
As a tester, the statements are short and pretests are strong and give me contribution XD
Another Chinese round! It's a pity that I won't be able to participate in it because of my classes :(
Anyway, I wish good luck to all participants!
Me too :(
If a $$$\text{Div-1 Round}$$$ and $$$\text{The Whole Education System}$$$ were dangling from a cliff, I would sacrifice $$$\text{The Whole Education System}$$$ to save the $$$\text{Div-1 Round}$$$
Yeah, as the saying of one of the problem setter, Chinese schools should be destroyed(Just for joking)
As a tester, I want contribution!
The problems are fun and interesting, so don't forget to participate!
Hope you all gain positive ratings Δ in this round!It is theoretically impossible sadly :/
It's not sad . If everyone gets positive rating then it won't remain fun and competitive.
You could have it both ways.
Create rolling sum that increases after each round, add the max rank to it each time. Each rank would be than sum + actual rank. Increases every time!. And yet distances between users stay the same! :D
Yeah I know its silly and impractical. But it is possible.
What if there was only 1 participant (initially rated 0) who solved all questions during the round? What about this "theoretical possibility"?
As a tester, the statements are short and pretests are strong and give me contribution XD
As a tester, I really recommend you to check your code carefully before submitting.
(btw : it's the first time for me to test in a CodeForces round)
rui_er! /se
upd: Why I got so many downvotes? I'm just a classmate of rui_er :(
Well I really wonder why I got so many downvotes. Maybe you disagree with me, but this is just a kind suggestion, so please be more friendly to a person who is still a new hand but always tries his best to do every job. :(
" I really recommend you to check your code carefully before submitting. "
Well, you are right. But why you guys didn't make the pretests of B strong? I think it's easy to be done. :)
I'm really sorry if this makes you confused, but I'm only a tester (not problem setter), so I don't know whether the pretests are strong enough. I started my virtual participation and tested some solutions and the constraints. This is the first time for me to do this job, so maybe I'm lack of experience. I'm sorry again and I'll try to work better next time. :)
Thanks for your reply. It's always hard to make something perfect in the first time. And I think you will do better in next contest.
Are contest timings decided by problem setters?
Yes. This unusual timing is because the problem setters are Chinese and they have to go to school the next day (maybe.
Chinese round!!! Chinese time!!! I can take part in the contest at school!!!
Chinese Round is coming!
Gaining positive rating $$$\Delta$$$ is not the most important thing that you got from a contest. Passing interesting problems and benefiting from them are the core purpose of participating in the contest. Otherwise, if everyone only want to increase rating, the utilitarians may fill the community.
Of course, getting high rating can be your motivation for progress. But I also wish you not go against your original intention of studying Computer Programing.
And, good luck! XD
Now found someone like me who also dislikes people yelling for rating here.Followed you buddy.
Why would you dislike someone for having a different motive than you?
I also don't have answer to this as somethings which are felt can't be described. It is a feeeeeling. I can't describe it.
Remember in my comment yelling is not meant as motive. motive is something different. some people just freak out on social media if they gain something. some people just cry here in the discussion when they suffer huge delta this deviates the purpose of this blog. 100 / 400 comments in every round discussion says about. "Hope I become expert/ specialist/master today!.
"Oh shit damn due to a silly mistake I lost 150 delta".
"OMG what a tough round".
"WTF the pretest 2".
This all things are fairly common in present comments in the announcement pages . And ya most popular trend.
"As a Tester ....shit"
Everything aside, you are a legend man. You are from Ukraine, study in China and have an Indian meme as your dp. XD
lmfao that said from your mouth lol
China is an actually a good country :D
I agree with you
Wow a newbie testers
Wow a pupil comment
Wow a pupil comment
Attention, time is unusual !!!
lollll :DD, I try to remind people but people don't like it =))
...[](
)
Codeforces Supremacy
As a tester, give me upvote!
Hope you can enjoy it. When you get stuck by one, you can just read problems after. :)
I saw lots of brilliant coder testing the round, maybe this means the contest won't be easy.
I want to become purple after finishing the contest(Daydreaming, of course.), so I'll try my best.
Hope everyone enjoys the fun of coding, like I do. Stay Cheeki Breeki :-)
The contest being hard or easy doesn't makes much difference in ratings outcome maybe because The contest is same for everyone....
Yeah, you're right.
What does it means- " In the upcoming round, you can use only Kotlin. You can read the code examples here."
That is for kotlin heros contest you can use only kotlin
Why downvotes, it wasn't needed. I just asked.
As a tester, the statements are short and pretests are strong and give me contribution XD
This is my second time to be a problem tester.Thanks to Imakf for giving this valuable opportunity.
The problems are well-prepared with interesting stories.Hope you enjoy them.
At last,good luck and have fun and get high rating
As a tester,please give me some contribution XD
Aaeria
ScarletS
This is my first time to be a codeforces tester, I feel glad. Thanks to all of the writers!
This round will be very interesting.
Wish everyone good luck!
(The statements are short and pretests are strong and give me contribution XD)
Colorful testers :D
Imagine getting + delta in a div1 as a low purple
you know you could at least read the comments before reposting a meme
...
Contribution > problem solving
An Orange-blue Round XD.
Feels great to see newbie in testers :)
As a grey colour, I'll solve A and attempt to solve B.
no, A will be too hard for you, sorry
Kuso!
just small predict
hahaha
You were right, A was too hard. But B wasn't. So I solved B
Good job!
Believe me! Just try to solve A and B quickly and you'll become specialist like me not long after that :)
As a problem solver, I want some contribution, too. XD
The start time is too early. Sad, Chinese Round should be destroyed.
Good luck to everyone!!!
As a problem solver, I want some contribution, too. XD
whenever you comment to get upvotes, every time get downvotes XD so please Stop now XD
May we know number of common problems between divisions?
As a resident of UTC+7 please give me more chinese rounds
More Chinese rounds — less rating, I warned you
Another 17:35 msk lover
As a contestant didn't do anything I want some contribution
At long there is a game whose time is suitable for me.
It will be evening in India and will be missing playing footbal.. Hope I give it my all and make it worthwhile
What mean rejected problems? see about it in almost all contest announcements. Why everybody write about it?
coordinator can reject problem, and it is often case if you are new in problemsetting
When you know you are going to lose rating, but still want to participate (Chinese round fact)
For me, it's just like when you know there is a round today, but you have classes :(
After reading prob D(lets go hiking)- others — Try to solve the problem. me — lets leave this and starts searching for hiking destinations to visit post Covid.
You must be kidding.
I fucking hate double in problem C I have right algorithm and because of double it doesn't accept on first pretest
No one tester noticed that statement of div1B is confusing? Really? I lost 0.5 hour and made 2 excess submissions because of that, and I am angry now
How to solve B ?
And what's wrong with this solution ?? WA
if mex is equal to n then ans is n+k otherwise answer can atmost be increased by 1.
Your method for calculating mex only works for sorted array.
Your logic for finding the mex is not correct because the input is not necessarily in sorted order. For example, if the input was
1 2 0, then the mex you find is1. But the correct mex for this input is3. Try applying the same logic while iterating over the sorted set of elements after you have inserted every element into the set.I think Problem C should not be in the position of C...
Very easy or very hard?
I actually write a math proof to verify my algorithm, but I believe there are people who had their fingers crossed and passed XD.
Can you give proof?
In which part?
First of all you can move all the mines and miners at negative positions to positive positions, since this doesn't affect the distance formula.
Then I simply try to proof that when using a line connecting miners and mines, there should not have any intersection.
nooo... i mean the logic part of it...like what should we take first the miner with the highest distance and coal with shortest distance(antisorted) or both in sorted orders? I took minimum of both cases lol by maintaining 4 priority queues xD.
simply sort the miners and mines by their distance to the origin, and pair them one by one.
My submission https://codeforces.net/contest/1496/submission/109585265
give proof
This is not meant to be proofed. Just guess and submit works fine.
Asking for the proofe here is asking for a formular. Google it.
Editorial gives nice proof.
This is no proof. They just draw a picture and say "It is that we must pair them in order."
It takes some time to write down my proof at the below link
i did the same thing, but why did it fail on pretest 2?? https://codeforces.net/contest/1496/submission/109623427
I think it is probably because the square part gives you overflow
https://ibb.co/mHNCJQL
That's nice!
But you did not write that while contest, did you?
The last line should be $$$(c^2 - a^2)(b^2 - d^2) < 0$$$ , Hence (a) is better than (b).
actually I did xd, but with a lot of note and calculation.
My contest proof version https://ibb.co/bLDDx0C LOL
just use triangle inequality
https://ibb.co/Xp8yVnS
What a nice proof!!
Very dumb
As a 中国人, I'm sorry I can't solve these problems. (Just started competitive coding with python)
What is in the 3rd pretest in div1C?
btw, div1B is elegant imo :)
I think 1B should have highlighted the fact the two inequality signs are different for the two people's possible moves. Also I should learn to read better :(.
Turns out I wrote the wrong thing then ):
Same to me. It seems that having wrong interpretation can pass all the samples and the first few pretests, especially when there is no explanation of the samples.
Wtf. I actually realized this after reading your comment.
Same T_T
Same :(
Can Any one tell why i am getting TLE? I am just using sort and sqrt functions This is my submission:https://codeforces.net/contest/1496/submission/109622532
multiset are very slow (something like 20 time slower than a sort), try with arrays of size n and counters to know where to add, or with vectors it should pass
Whats the approach for Div2 D. I am getting WA on pretest 9.
Div 1 D has such a scary time limit. I spent a bunch of time doubting if $$$\mathcal{O}(n^2 m)$$$ would pass, and it turns out my $$$\mathcal{O}(n^2 m)$$$ passed pretests in 2.13s/2.5s. It doesn't have any optimisations, so the runtime should be fairly independent of the input, but still, I'm scared of the systests.
anybody who can explain what's the deal with using Fast io and setprecision together resulting in TLE for C ??
Because you read the input in doubles when the input is integers. Doubles read for a long time. It will be faster if you read ints and convert into doubles.
Also, I read at someplaces that sorting doubles is costly. Is that true?
I don't know
I think the differentiation of problem C is TOO low.
[Div1 B] Am I the only one to not notice that the conditions for x and y are opposite and made 3 WA submissions?
I also didn't notice that at first. Fortunately I spotted that before submitting anything.
I noticed it now :(
what's with the 4th pretest of div2 c?
Just don't take the container in which you are storing miners and mines of long double type, take it of int type. And rather take miner[i]*miner[i] + mine[i]*mine[i] as a long double variable to pass to sqrt function. And it passed for me after a number of Time Limit errors. Edit : also sqrtl() in place of sqrt()
and why is that?
Can anyone explain their approach for Problem C ? Thanx in advance .
separate the x axis and y axis values and take the absolute values only . After that sort both x-axis and y-axis arrays . Now we can pair same index values in both arrays .
Implemented the same ! but wrong answer :(
Int is not enough to store square of coordinates
How to D?
I am not sure if this correct approach , I think answer will be always $$$1$$$ or $$$0$$$ .Answer will be $$$1$$$ only when there exist some index $$$i$$$ such that array is decreasing in both right and left direction of index $$$i$$$ and size of the maximum decreasing sub array in both directions are equal,even and maximum in the whole array.
Update this approach is correct : 109629126
Rewrite input as mountain profile. Then first player only go down, and second player only go up. The players can't collide. First player should always start on peak. Otherwise, if he is in hole, he can't do any move, if he is on slope, second player can start under first player. Find for every peak its length to the left and to the right. If there are two peaks with same maximum length to the left/right, then first player always lose. Assume he starts on one peak, then second player will start on bottom of another peak, and since he is second, when they walk same distance, the first player will must do move. Now, we have the only peak with its length to left and right. This is the only position, where first player has chance to win. So the answer is either 0 or 1. First player wins if and only if the lengths of peak are equal in both sides and even.
First player wins if and only if the lengths of peak are equal in both sides and even.
Shouldn't it be odd ??
Oh, yes, depends on your definition of length. I defined length as number of edges: here $$$[1, 2, 6, 5, 4, 3]$$$ length to the left is $$$2$$$ and to the right is $$$3$$$.
Hm, right
In, div2 C, using a vector of double caused TLE, while a vector of long long passed the pretests :(
same. wasted 1 hr :)
why is it that the vector of double givees tle?
I misread statement from problem B and I thought that both players could make the same movements (I didn't see that $$$p_{y'} > p_{y}$$$). Goodbye div1 :(
I'm really surprised that all my submissions reached pretest 7.
lol, it happened to me too :(
so unfortunate
When you read Div 2. D as py′<py and spend 1 hour solving the wrong problem ://
That is bad problem statement. I did read it like 25 times before noticing.
Providing the explanation in problem D before hand would have saved a lot of time and maybe that could have been utilized in writing better solution.
I was still solving it for the same until I saw your comment. Still getting a positive delta but could have done better.
What was Div1B Pretest 7?
Div.2 E / Div.1 C has elegant solution, just think about a pattern.
What if you clear every $$$k$$$-th row? Think about suitable $$$k$$$.
Upd. Managed to construct a solution which uses regexes (Perl): 109637022
Can someone explain why I got TLE in D2C? :((((
https://codeforces.net/contest/1496/submission/109611221
use long long int instead of long double, the sort will be faster (I know it's weird)
Why my code is wrong in Div2C?
https://pastebin.com/zwS43AAZ
firstly the value you set ans to is too low, it can be up to 2 10^13, define it by the first value and it should become correct (to my mind). However, according to others bad experience, you should use vector of long long int and not long double because elsewise sort will be too slow on test 4
In recent contests I spent most of the time in asking myself, "How could I missunderstood the problem statement so that my solution does not work?"
Of course it is not allways the reason for WA, but if something does not work as expected, than usually such missunderstanding is the reason.
Would've really appreciated if the sample explanation for B were added beforehand. Thought the p’ > p signs were same for both players and solved for that. I take full blame for my mistake, but would've been nicer if at least one simple simulation were shown in notes, just sucks to lose so much time on a misread. Gotta be more careful I guess
The FST rate of div1B looks so scary...I am so curious about the pitfalls...
Why is this solution giving TLE for 1496C?
Question Link: 1496C Submission Link: 109603686
The solution is under the constraints and the approach and method is same as most of the accepted solutions that I have seen. Why is my particular solution giving TLE?
dont use long double in vector
Okay, using long long in vector worked, but why? Both long double and double give TLE, why? I have seen accepted answers using double in vector?
Please tell whats wrong with these solutions ?? (Today's div2-c)
Link1
Link2
I was at ~200 position after solving 2nd problem then there comes this problem :(.
Use vector long long vect1,vect2 rather than long double vect1,vect2. I had the same problem made 8 submissions before making the right change. Sorting is O(nlogn) but there is considerable overhead sorting long doubles than integers. Stupid C++ :)
Problem statement for this problem "Let's Go Hiking" was very fuzzy. It could have been more clear with test case explanation.
I think the number of pretests of Div2D/1B are too few...
Damn D's are failing fast.
I can't understand why I have got TLE for problem C in Div.2 for this solution: https://codeforces.net/problemset/submission/1496/109589906
but OK for this solution: https://codeforces.net/problemset/submission/1496/109596686
how to solve D div1 ?
A solution should be available on the editorial, but here's an outline of my thought process.
Precompute the pairwise distances between all nodes. Then, we'll compute the answer separately for each pair of nodes.
The key observation is that a pair of nodes has answer zero if there are multiple shortest paths between them. We can prove that any edge on a shortest path from i to j must be in a BFS tree that can be rooted at both i and j, and if multiple shortest paths exist, this will necessarily create a cycle.
The shortest path from i to j is unique if, for every d from 0 to dist[i][j], there exists a single node k such that dist[i][k] = d and dist[k][j] = dist[i][j] — d. We can check this criterion in O(n).
Then, the BFS tree becomes a forest containing a tree rooted at each node on the shortest path from i to j. We can then show that vertex k not on the shortest path such that dist[i][k] = a and dist[j][k] = b must be connected to a parent vertex p satisfying dist[i][p] = a-1 and dist[j][p] = b-1. Therefore, we can compute the answer by multiplying together the number of possible parents for each vertex.
We can thus deal with each pair of vertices in $$$O(n+m)$$$ time, so the total complexity is $$$O(n^2(n+m)).$$$
It is more clear than the tutorial, thanks.
Thanks for the explanation.
I am your fan xd
Thanks for this round!!! :>
There is a huge difference of who solved A,B,C and who solved A,B,C. :(
How ?
There are only 544 people Passed the D.So who passed A,B,C quickly will make great grade.
Hey could anyone explain when using long double rather than long long, its giving TLE on div2C?(https://codeforces.net/contest/1496/submission/109596148) (https://codeforces.net/contest/1496/submission/109613452) I know sorting has considerable overloads for long double but still wouldnt the complexity still be O(N*64*LOG(N*64))?
Solution for Div.1 C : Consider partitioning about columns, that is mark complete columns as empty for columns 1, 4, 7 .... in 1 based indexing. Now between each 2 consecutive columns, if there is at least 1 cell that was originally empty, eg. in column 2 and 3 while considering columns 1 and 4, join both the columns using that row's elements in between them. Otherwise join them by the first row if no such empty cells exist. Finally if the number of columns are divisible by 3, we have to join the last column elements to the rest of the elements joined till now. To do that, for each such original empty cell in the last column, mark it's previous column (same row) element as empty.
Again, not good presets XD
Why is my code incorrect: https://codeforces.net/contest/1496/submission/109627982
At least, we can show that the solution must be 0 or 1, but your output for test 5 is 57.
Why is Problem E easier than D —— even Problem B?
Oh,I'd made a mistake.Now fixed.
You can just edit your comment...
:D finally fst on 1B, because of some small bugs.
But it's still a nice trip, isn't it?
In the end, my rank reduced by 60. Luckily I still become an IGM, with various motions in my heart.
It's an exciting and unforgettable day for me, although this round maybe my last time to participate in a codeforces round.
It's time for me to stop studying Computer Programing, because of too many hard competitions and the stress of studying subjects. Otherwise I must try my best to become a top OIer in China, it's too hard for me ...
Wish you all good luck! And, thanks. :D
Have a good trip and hope you'll achieve your target! :)
My code is printing 1 on my pc and ideone but on codeforces its printing 0.
Whats wrong?
mentioning: MikeMirzayanov
For div.2 C problem. Can someone tell me why is 109605593 getting TLE and 109609603 getting accepted when both are having the same logic?
Just printf statement is different. %.15f in one while %.15lf in second.
"strong" pretests for B. I think that there aren't too many situations but the pretests didn't include those. Anyway, you should consider all the possible situations. :(
Pretests for problem D were very weak!! I mean look at the 30th case and 20th test case, how can one not include it in the pretests? Anyway it didn't affect my ratings but still those got WA on those test cases are unlucky :(
With many participants happened this: one of the solutions got TLE, the other one got OK, but they have the same logic (problem Div.2-C).
Why??
Thanks for the round! I thought the problems were very high-quality, and I enjoyed thinking through them for a few hours. (This was probably the most intense CF round I've ever taken--finishing C and solving D in the last ten minutes saved me on the order of 150 rating.)
One point of criticism: I'm not entirely sure why B did not use multitesting. There's no particular reason it would have been more annoying to write up if multiple test cases were included in each input, and this sort of problem (i.e., problems with only a handful of possible answers where determining which one is correct relies on checking some fixed criteria) always seem to lead some competitors to janky solutions that break down on relatively rare edge cases. The resulting FSTs would have been avoidable if multitesting was employed: for example, many solutions FSTed on a case with $$$n = 5$$$, and this could easily be prevented by a single batch test containing all inputs from $$$n = 2$$$ to $$$n = 7.$$$
Because of the pretest of div2D/div1B , lots of people are disappointed.
But you should consider all the details.
If you can't consider all the details , please improve yourself , do not blame the problem.
how weak 2D's pretests are!
sorry I accidently downvoted you .... consider you upvotes to be (current_votes+2)
sorry I accidently downvoted you .... consider you upvotes to be (current_votes+4)
Proof of Problem C that we should not have intersecting lines in the midway somewhere.
EDIT : D22 — D12 should be in the next equation. I hope you all can understand it. Please tell me in the comments if you have any issue in this. Also i missed to write +k when simplifying D22.
Well, i think it can be proved by
https://imgtu.com/i/6Y36II
Sorry i don't know how to insert a picture
Nice and short proof!!
$$$OA+AB \geq AB$$$
I think you want to say $$$OA+OB \geq AB$$$
Yes, you're right, it was a mistake
sto IGM MonkeyKing!!
It can also be proved by looking at the scoreboard.
Can't agree more :)
Nice contest, but author of problem F should learn the difference between a circle and a square.
Problem C
Can anyone proof it to me.
https://codeforces.net/blog/entry/88497?#comment-769345
It's clear now
Thank you.
Less participation = -vve rating
As a tester of some past contests, did the testers who say "pretests are strong" really check the pretests? I sometimes checked the (sys.) test during testing, but I never see the tasks on Polygon(because almost always testers don't access or don't have READ rights on there) during testing and then I couldn't check which tests are included in the PT.
This is a problem.. It seems like testers nowadays are just spamming "Statements are short and pretests are strong" to get contribution. Logically not every round they test can be that perfect, yet I see these comments on every round.
В русской версии условия Div2A опечатка в пояснении к примерам. Написано, что пояснение ко второму примеру, хотя оно к третьему
Can anyone tell me why this doesn't work for problem B? I think my idea is correct.
There is something called "Time Complexity". Learn it first...
Ok, I don't know much about time complexity, but my code gives me wrong output, not TLE.
i think change
to
Thank you, but it gives me exactly same output as before. On first test case: 4 4 3 3 3
I checked your code and found two problems. First mex_ can be from 0 to n but your code check 0 to n — 1 change
to
Second when append new value recompute max and mex value. Because it can change. But your code only compute once.
In the rating predictor why less positive delta is showing? On what factors rating changes are dependent upon?
Don't worry about your rating (bhaiya), just enjoy problem solving (hacking)!
D is good and my clean implementation below.
109642740
submission 1: https://codeforces.net/contest/1496/submission/109647192 submission 2: https://codeforces.net/contest/1496/submission/109645519 can someone tell me why the first code is accepted and the second code is giving TLE ???
109652804 Using "cin" to read a lot of "double" maybe too slow.
but in both of the solution, I am using cin for input
Hi guys. Something really strange happened to me.
Today I attended cf round #706. For some reason, it gave me this warning. During the contest, I resubmitted once and changed the "int" to "ll." Now im not so sure why it gave me this warning? Is there anything wrong with resubmitting the exact same solution of mine? I think there may be an issue with the system or something. Currently, my submissions are "skipped" for this recent contest: but I still don't see the fault of re submitting. Could you please take a look at this @MikeMirzayanov. If someone could help me fix this issue, that would be great. Thank you.
Upd: for further evidence, I received 2 messages from the "system," which means that I "copied the code from my own code."
?
FSTForces
In Div 1 E's sample,
I know 114514, 1919810 are famous (unhealthy) slangs for Japanese, and 2333.. is a slang for Chinese.
But I don't find the meaning of 19260817, 623532, 7175. Do they have special meanings?
19260817 is the birthday of a famous man in China.
623532 and 7175 is the melody of a song in Touhou Project I think.
Exactly right.
a famous man(
In first line, I read "Daniel_yuan waiting" :p
May we know number of common problems between divisions?