When you increase the cost of something you get less of it. This is what the proposed rule would do.

The fact that proposed rule does not solve all problems is not a good argument. The litmus test ought to be whether the effects are a net positive.

Edit: Many of the same points were made in the other thread (linked in the original post), I didn't see it before I wrote my post.

Good idea. Perhaps 5 or 10 minutes is too tight. What about 15-30 minutes? If you clearly state that "by clicking this button the contest will be rated for you", I don't see any big problems with it.

I have previously voiced my concern that the "no submission implies not rated" rule is easily abused.

Suppose a contestant struggles to solve any problem in the first 5, 10, 15, 30, 60 or 90 minutes of a contest, and they have not yet submitted anything. In other words, our contestant has a poor start. What options do they face?

Option 1, submit at least one solution and continue: The contestant accepts the poor start and high likelihood of negative delta.

Option 2, resign and do not submit anything: The contestant resigns (decides not to submit anything) which leads to a guaranteed outcome of zero delta.

So we have "high likelihood of negative delta" vs "guaranteed zero delta". I think many will find the latter option more attractive. But clearly this creates perverse incentives. It creates a situation where: 1) if you get a good start and/or have integrity you get rated 2) if you have a poor start and/or have low integrity you are not rated

Another way to put it is: the rating of the contestant will not reflect their failure in the contest.

Anyway, your suggestion does not perfectly solve the problem outlined above. But it is a good start.

Use PyPy unless you have a good reason not to.

After switching from Python3.8.2 to PyPy3.7.0 it passes: exactly the same code using PyPy3.7.0

1)

I don't think stagnation is a good reason to quit. Some good reasons are: you'd rather spend your time doing something else, you no longer enjoy competitive-programming, a different activity better aligns with your long term goals.

You suspect your stagnation is due to your innate stupidity. Well, let's say you quit competitive-programming. Then what? This fundamental problem, your stupidity, will be a handicap in any other intellectual pursuit. In other words, you will face the same problem if you replace competitive-programming with chess, poker, physics, mathematics, literature, or any other intellectual activity.

To be frank, I doubt you have reached your potential. Almost nobody does. You are already at a decent level and it is expected that improvement requires more work now than it did before.

2)

This is just my hypothesis, but I think being strong in mathematics is more important than people realize. If you look at the top competitors on this site and their background, many have very strong math backgrounds (e.g. competed in math Olympiad). Um_nik's advice, to just solve many problems, might be a sensible plan for him and others with similar background. But is just solving many problems a good strategy for you? In other words, if solving many problems is not producing the results you want, maybe try something different, like study compsci theory and mathematics?

Just my two cents.

I really liked problem C as it tests your ability to read, understand and reason about a piece of pseudocode. Very useful practice and skill.

We appreciate it, but unfortunately most of us are incapable of returning the favor by creating Div1. rounds.

To the div1 contestants who are unhappy about the lack of rounds: why don't you take turns creating rounds? One week tourist creates a round, next week Um_nik does the same, and so on. This way you solve the scarcity-of-div1-rounds problem yourselves.

I don't see many other options as the pool of individuals who are capable of creating good div1 problems is small.

Starts in 5min

This contest starts in 20min.

Thank you sir!

Would you consider rescheduling it as it conflicts with the ABC contest?

Enjoyed the contest, thanks!

Of the problems I worked on: A, C, D were very good. I did not like B. In general I hate these problems with one-line solutions. Anyone else?

Your rating does not change if you do not submit anything during contest. Have you considered removing this rule?

I don't know if it is currently the case, but it is easy to abuse this rule:

• Spend some (1-5) minutes at the start of the contest to get an overview of the problems.

• Based on this overview decide whether to participate or not.

Perhaps it is not a big problem, but I suspect it is by the amount of registered users that do not participate in the average contest.

Great site, great problems, great book. Thanks pllk.

Good explanation.

I think any radical change will make many veterans unhappy.

Look forward to this round. Thanks for offering div 3 and 4!

I agree with you, it's frustrating when constraints are not balanced for your language of choice. But to be fair, I doubt they have the resources to balance constraints for each problem and each language/compiler/interpreter they support.

Use sys.stdin.readline() instead of input()

Just replace input() with sys.stdin.readline() (import sys before obviously). Input() is too slow, need to read number(s) faster.

For problem B using Pypy3 (Python), O(n log n) solutions TLE on test case 26. I saw other Python solutions with the same complexity which failed as well.

It seems to me you have not done a good job of balancing time constraint for the language.

My submission which TLE on test case 26

UPD: The cause seems to be input handling, people who used sys.stdin.readline() instead of input() passed.

Thank you for hosting div4 and I encourage you to do so again in the future.

Looks interesting, thanks for sharing.

Thanks for everything Mike.

Happy new year and good luck to you and everyone else.

I wanted to upvote but accidentally downvoted. Sorry about that.

I'm new too and getting crushed in my first 4 contests. I solve mostly problem A in div 2, maybe B and I never have time to attempt C or harder problems.

If you look at the rating graphs of other users, even the top ones, they often have a dip (falling rating) in the beginning so I think it is normal.

Just experiment with it. Run contests with different formats and let the "market" decide.

This is how it is done in poker and chess. In chess you have classical, rapid and blitz time formats and many variants of chess (Fischer Random most prominently). With poker you equally have many different formats and variants. Another competitive programming site (CC) has challenge contests that last over many days.

Additional options and variety is usually a good thing. In any case, there is not much harm in trying, worst case is the contest with new format is not popular and you never host it again.