The system message about CodeTON Round 9 said:

We are pleased to inform about your award for "CodeTON Round 9". The first 255 participants will receive prizes in USDT cryptocurrency in the TON network. Congratulations!

Please provide your TON wallet address by link: https://codeforces.net/settings/wallets. Please be careful when filling in.

The deadline is 23:59 December 8, 2024 (UTC). If you don't do this, then, unfortunately, we won't be able to transfer the prize to you.

Join the TON, then register a wallet, follow one of these links: https://tonkeeper.com/ or https://wallet.ton.org/.

It's said that I would receive prizes in USDT, and recommended two wallets. The two wallets are the same as which mentioned in previous round messages.

I was using https://wallet.ton.org/ to receive prizes for previous round. But as far as I know this wallet is just for TON and doesn't support USDT.

I have little knowledge in cryptocurrency. So here I kindly ask how can we receive our prizes.

The TON foundation team, please tell whether I should change a wallet, or the original would work. If yes, then please post a tutorial on how should we change to a new wallet, as the prizes isn't a small number.

Hi!

I'm trying to get my TON-coins for CodeTON-Round 3.

There's a E-Mail checking box at the wallet page, but I can't recieve my E-mail Code for that.

I've tried 3 times and have waited for ~10mins, just the length of the useful period of the code.

I've checked my Email inbox for registering Codeforces(just the Email box in my user page) many times.

I'm currently using mail.qq.com which is a widely used email website in China.

Does anyone had the same problem, or how can I recieve my E-mail code?

Thanks!

UPD 1: Note that I have recieved the announcement mail for the next Round.

When I'm solving problems, I prefer to see other contestants' performances in the contest than the ranklist of problem solving.

But the "standings" button is not linked to that and I need to load 2 more pages to see that.

Also when you get into the problems from contests' pages, the button is linked the contest standings, I often can't notice the difference between these two same buttons, and have mis-clicked it many times.

MikeMirzayanov Could you please link the "standings" button into the contest's standings, regardless of how solvers enter the problem, Thanks!

Sorry for bad English or (maybe) wrong spellings.

Change the link to the contests' standings[likes:0,option1]Keep the original link[likes:0,option2]

Using CF's Feature to pass CF1705F in practise

Sill useful till 2022/7/21 9:27, the post time.

It's found that A well known blog has talked about that trick two years ago, you can read (and upvote) that because that's really interesting (and maybe useful).

Let's think of randomize.

For two adjacent problems $$${a_i,a_{i+1}}$$$, randomly question once.

It can be easily calculated that the posibility of instantly getting the correct answer is $$$\frac{1}{2}$$$.

If we get the correct answer, go on querying $$${a_{i+2},a_{i+3}}$$$.

For other possiblilties, we can know the relationship between $$${a_i,a_{i+1}}$$$, so we can go on querying $$${a_{i+1},a_{i+2}}$$$.

Finally, we query once to get the answer of the last problem. By using the relationships, we can get the overall answer.

The expected query number is $$${\frac{2}{3}n+2}$$$.

The expected failure chance per testcase is $$${\frac{1}{3}}$$$.

But there is a feature that CF rejudges the TLE submissions per testcase $$$3$$$ times.

So, every time we exceed query limit, while(1) instantly to get TLE instead of WA for rejudging.

This makes the failure chance per testcase $$$\frac{1}{27}$$$, making the overall pass chance $$$\frac{1}{10}$$$.

In practise, we just need to resubmit several times to get AC.

In contests, this method can be used in randomized solutions to make the AC possibility larger.

Accepted link: 164438874 and 164437895

(Mike, plz don't fix this.It's so useful that... qwq)

If your don't agree with this blog,have a better way dealing with this kind of problems,or think i need to improve my blog skills,just tell me at the comments

Sorry for my poor English skills:(

I cant bear more.I have to write a blog about it.

Eaxmples

1557D

1555E

1549D

1557C-calculating C(a,b)in log(n)'s time

1550D

What's wrong on these problems

I started programming on cf because my friends told me that cf problems need coders's thinking more than coding.

But now things started to change.

These problem can just stop coders from solving them because they don't know a certain algorithm,even if they found the correct way of solving them.

What's more,most of these problems' difficulties are on the data sculptures.It's not the purpose of giving problems.

I wonder how many blue or less coders know the and can use algorithms like C(a,b) or segment_tree well.

Even worse

We use our own computer and our own Internet access when coding.When we don't know how to use/type a certain algorithm,most of us thought of searching it online at once.

normal coders want to solve the problem before the contest ends,Experienced coders want to solve them faster.All of them will choose to copy-paste when facing a data-sculpture which need lots of time coding.

So here comes copy-paste forces.Guys who had written a similar algorithm before can debug faster and solve faster,who hadn't will have to find one on the Internet and took more time.

Problems become useless when falling into this hole.

My suggestions and thoughts

These problems start to exist because Div2 problems are normally given by Div1 coders.They can use these algorithms well because they are Div1 coders,but most of us can't.

I hope that these kind of problems are minimized and large data sculptures will only exist on problems for experienced cpers which need more thinking and calculating,not just make some small changes on the original data sculptures.

• I sorted them with the number of people and soon find...
• what's wrong with it?It's really weird.
• Is there something wrong with my computer or network?
• UPD:I find that this situation happens whatever I sort them with the number of people
• UPD2:I find that the only active member showed(I dont know why his name is still in it) in this organization's page is not not in this organization now.I guess this is the reason that the membercount of it is wrong.(the other member(1 member) is still in this organization)

I have seen many people whose contribution is below zero and I think it’s impossible. Can anyone tell me why?

UPD：now possible...