In Div.1 E, accroding to validator, sum of N is guaranteed to be less than 80. And its not shown in the statements.

If the validator was corrected to fit the statement, only jiangly's code will be able to pass (125ms *10 = 1250ms), among all 4 accepted codes till now.

I don't know why but there's always a 2~3 weeks' delay in the prize delivery.

For example, I recieved prize for CodeTON Round 9 on December 11, and the round was held on November 23.

I failed to pass G because the stack limit of the problem is too small, like much smaller than the memory limit. Shouldn't the stack size be the same as the memory limit?

link. After comparing my solution with some other accepted ones I'm really sure that it should have been right.

Will the prizes be sent with USDT, which might mean we should change a wallet, or it will be transfered into TON?

Div.1 F1 and Div.1 F2 are completely different problems. I don't understand why this kind of subtask is allowed in a cf contest.

I got the same idea and had a bad time inplementing that :)

The constant factor is too large for the segtree part and I can only store the 2 biggest values. Beside that some optimizations on the constant factor is also needed for me.

Anyway the data was weak enough for that to pass 278190335

I have no access to problem tags.

I can't uphack solutions in all contests I just randomly chose. Actually sometime in the past I could so it might be determined by something else.

The biggest problem is actually Coach Mode in gym. Luckily if a gym contest is kindof "private", then I have no access to it.

I wasn't assigned to any of the rooms during the contest.

I checked my submissions' page (the one which can be opened in the "standings"), and there isn't any room information as it used to be in the first line.

As a result of that, I can't make any hacks (and I thinks my solutions can't be hacked by others too).

I checked the standings and saw many people with the same problem.

I asked about that during the contest and got replied with "no comment".

Will this happen in the next contest? or There's some rules about this that I didn't noticed?

Maybe creating different rooms for each problem will be better. For example, the ratings of the participants gets closer as the problem difficulty gets higher.

Harmony_'s solution is still running...(On test 29 now)

It has been ~1h for it to be runnning.

Hope that won't take another 1h in system test.

I was just looking for a formula to choose the right algorithm.

Soon found that the formula in the statement for score calculating can be calculated dynamically. So I choose the algorithm with highest score to use.

Then I found that each tenant is an individual part in the final score. By going farther in the formula I found that their effect on scores increase in a speed of w_i^2/w_std, which w_std is the std fail-count. I assume an evict gives same effect on different tenants, so the tenant with smallest w_i^2/w_std will be chosen.

I did some changes in LRU like adding Cnt/4 to the priority, which gives about 500 points.

I tried second chance LRU, but it worked worse.

I also used something similar to what nweek said to optimize tenant/algorithm choosing.

In the end I'm actually swapping between LRU, 70%LRU+30%LFU, 30%LRU+70%LFU, LFU algorithms.

They wont. I viewed previous contests and the solutions are unavailiable.

Can anyone share an algorithm which got >=14000pts in contest?

I can only do 13700 by dynamic swapping between LRU and LFU.

20 people in 200 points' difference... There must be a huge rank reorder after system test...

A=B<E<D<C in my opinion.

C is really great.

D is boring and the solution is so obvious that it make me think that there are many problems similar to it.

E is really even easier. I guess many people can't solve it because it's an E.

I think after swapping C and E the ranklist will remain the same.

Oh I forgot to mention it. Now it’s fixed. Thanks!

Hint: 1e9*1e9=1e18

How to solve F?

I turn the problem into this:

There's an array S indexed from -n to n, the number on index 0 is 1, rest is 0.

Do n operations, on each operation there's S[i]/sum(S) possibility to choose index i, add 1 to S[i], then P possibility to add S[i+1] 1, 1-P possibility to add S[i-1] 1.

Output the possibility to make S[-n...-1] both 0 after n operations.

But I have no idea how to solve this :(

I don't have any problems in connecting, vpn can't help me to speedup cf's mails sended to me :(

Speed Forces in Div.1 (

Can't use the voting system correctly, could anyone helps a bit?

[too many auto comments so I deleted this one]

Auto comment: topic has been updated by lexiyvv (previous revision, new revision, compare).

Time to get the blog back to the recent actions XD

here

Did you write it before the contest ended? Maybe that is a kind of violation of rules.

Auto comment: topic has been updated by lexiyvv (previous revision, new revision, compare).

No more algorithm-reading problems plz No more algorithm-reading problems plz No more algorithm-reading problems plz

As a Chinese,I spent 1 hour trying to convert the TON coins I received in codeTON round 1,into RMB,and failed.

I solved C using bitset with O(n^3/32).

Is that the correct solution???

If yes, then C is a completely failure.

I have another suggestion-Dynamic Ranks

last 20% of Div1's rating will be calculated with first 20% of Div2 (with an Average Performance of A,B added on Problem A and B,as penaltys for Div1 of ranking low) and they won't affect Div2 20%'s rating change

First 80% of Div1 will calc with last 20% of Div1(but won't affect last 20%'s rating) and also try to keep the rating change sum to 0

Div2 calculated as usual.

That's a great idea,as I never gain rating in Div 1s.

But how will Div 1.5s be held?

With Div 2 and Relpace Div1(LGMs will speedcode)

or Div 1.5 only(That will kill specialists and below)

or Div 2+ Div 1.5 +Div 1(too little people at Div1/1.5)?

I think Codeforces Round #XXX(Div 3+Div 1.5)might be great,But many 1600s still need to have Prob A-B to have different ranks,and solving only A as 1600 will also be frustrating with rating drops.

I recommend to keep it because you just got -8 but getting the rarest rating change in cf.

D2 should have worthed more.

Sad to see lots of people solved D2 ranked below people who don't.

maybe D1(750) + D2(1250) will be much better.

As previous contests shows: [](https://codeforces.me/blog/entry/57721) [](https://codeforces.me/blog/entry/50404) [](https://codeforces.me/blog/entry/23515) [](https://codeforces.me/blog/entry/6677) Programmers usually don't remember the festival unless the announcement notices it...

So plz don't mention it next time(

nobody reads tags expect me

agree，but make the start time 1 hr earlier please or the Chinese coders will go to bed at 1:35 : (

Handle Leng th

I think many schoolchild from the Saratov region didn't plan to participate until they see UPD2

Codeforces round #745(Div.1)+Codeforces round #745(Div.2)=Codeforces round #758(Div.1+Div.2)

Very great contest,but I think the time limit for C can be 2s.

My point is not on A.I decided to solve it after D.

now found it the worst decision ever.

More,only 5000/9000 participants submitted A.It's not a good thing for cf.

FSTforces

Chinese problemsetting forces invading Russia lol

Accroding to tradition,This Contest might be delayed:(

Are there any provements for C that the deepest subtree erase is always right?

{deleted]

You don't need to learn it now.CCF just had water in it's mind.Don't pay too much attention on that F*** problem

Our friends at Harbour.Space don't have any messages for us this time?

So this round is about pikachu?

It might be my problem.

I used it as an exampe of calculating C(a,b) in log(n)'s time

I think most cpers like me can't write a C(a,b) correctly without the help of internet.

Why readers are downvoting?Tell me to help me increase my blog writing skills or let me know how you deal with these problems better than me.

look at mine :(

I HATE GCD

wonder how many guys copy-pasted their segment_tree for E from the Internet

Just because he is Karry5307.

Suprisingly found that Errichto means Resolution in Basque.

you can also give the pictures of chat between you and him from the time before the contest begins till end.

your debugging lines and wrong submissions are also powerful evidences.

you can also send messages to MikeMirzayanov because he is busy and might didn't notice this.

UPD:Thanks for everyone's downvotes,now you won't see my words if you don't want to because it's in spoiler now,but my suggestions remains if it will help even a bit

then:

Codeforces Global Round 15 Jul/25/2021 22:35UTC+8 02:30 Before start 8 days Before registration 5 days

dangerous

"Educational"

Mathforces and Messforces

what‘s rainboy’s name？

Don't complain about #707 any more everyone...Maybe cf is thinking about a no-pretest contest at that time

sorry to make the first comment meaningless

amazing fact：in the first few minutes after the announcement is published，the announcement‘s rating is negative（？？？

Is it more difficult than a CF Div2?The first ARC I participate make me doubt my ability:(

• It seems like that Harbor.Space University Isn't Praised by most of the users:|
• \----/
• \../ -100+
• \/
• And It Seems Like You Joined The Choice Game:
• A.Your money will be a part of the scholarship
• B.You get the scholarship(which is made by actually others' application fee)
• (The same thought as harsh_joshi's)
• many people choose A(sadly)and this is how the Uni earns money.
• in conclution,this is not a scam.it's buying the lottery.

Codeforces new rule:no one's face should be seen on the profile picture

But it's still showed maxint... - anything wrong with my network?

Auto comment: topic has been updated by lexiyvv (previous revision, new revision, compare).

By the way,It isn't the last time...

[deleted-auto-comment]

Auto comment: topic has been updated by lexiyvv (previous revision, new revision, compare).

It's not a joke.My computer still shows it after refreshing the page.

yes.but submissions wrong on examples -0 penalty.

• every wrong submission:penalty(the time you use to solve ecah questions added together)+10.
• the more penalty you get the worse rank you get.
• the people solve more problems is always before the people solve less questions.
• example:
• User Penalty Solved Rank
• A 100 3 4
• B 50 3 3
• C 200 4 1
• D 500 4 2
• 4<3,so C and D 's rank is before A and B 's.
• 200<500,so C 's rank is before D 's.
• 50<100,so B 's rank is before A 's.
• This is ICPC mode,so no points but only penalty and the number of solved problems.

Actually Mike's name is more common than others:)

vovuh sent this announcement when the contest is going to begin in exactly 30 hours:)

how do you save it?I pressed the "Image" button but nothing happens:(

how do you save it?I pressed the "Image" button but nothing happens:(

1000 lines of code just make it stucked... UPD:Just like this code

This it a meaningful contest.It represents the end of last week's $$$(NOT)_serious$$$ problem.

Oh I didn't find that there is something wrong on the rating change page of the contest. - +1012 is correct.

5000+fake accounts this time:(

Top2: yet_another_ATS +894 Codeforces Round #640 (Div. 4) UPD: It's 3rd.

Codeforces Round 1000(Div.10) Total:20000 Participants:10 Out of Competition:19990

• Last contest with "read all the problems" didn't end well,and this contest with this sentence doesn't start well:(
• so,just change it into"read all the problems after system test ends" :)

[deleted]

Have anyone noticed that the checker comment in this round is "ok good job (xx test cases)"? Phoenix even makes the checker comment enjoyable:)

bilibil"l"?!

I also find that the result of submissions always appears faster in the problem page of contests.

It will be great if there is no links in the statements:) -> it always takes me a long time to open them.:(

more interesting

I'm really confused that when I choose not to see unoffical participants I see load of yellow and red names in the first 100.How are the D2 participants' rank calculated?Does Codeforces calculate our ranks removing them?