What is the mapping between them? Timus has a lot of problems rated < 200, but they also have problems rated above 10,000. The problems also seem more chaotic. I've done some of the first problems, and even the easiest require some tricky thought, but then if I scroll down to more hard problems, some of those are easy.
Does there exist some statistics for comparing timus and cf problems? Or do anyone whos used both sites have an opinion?
It's just a number, why do you care so much?
If I'm not allowed to care about stuff that can be represented by numbers, why would I even be on this website?
More serious answer: I just like to set goals based on difficulty. Like practice on codeforces. If I try to do a 2800 problem, I give up quickly. But if its a 2000 problem, I know it will be difficult, but I should be able to solve it if I think about it for a while. Maybe this is a bad habit, but thats how my psychology works. So it'd be nice to have the same for timus (without having to spend a lot of time doing too easy and too hard problems to gain an independent intuition for how the timus scoring system works).
Ok, got it.
CF problem difficulty system is broken one way, Timus is broken the other way. It doesn't really make sense to compare the two. The problem style is very different. Plus most of the problems on Timus are more than 10 years old, and while the difficulty number can change with time (unlike CF), it still has the same drawbacks as trying to practice on old CF problems, if you tried that. For some problems the main difficulty is just thinking and that hasn't changed much in 5 years. For other problems it is the algorithms or standard ideas used, which could have become more popular with time.
I would suggest you to try 2-3 problems with difficulties around 200, 300, 400, 600, 800 to find a difficulty range that is not too easy and not too hard for you, that shouldn't take too much time, and you still will be solving problems which is more useful than searching for difficulty conversion function.
What's wrong with practicing old CF problems?
Nothing wrong with that, but you might feel like the problem difficulties are broken.
Ok, thanks for the response. Separate question: do you not recommend practicing on timus? The reason I wanted to use that website was actually because you recommended it in a blog. But that blog was a while, so has things changed, or do you still think its good to practice there?
I think it's as good a place as any. My main point is to practice in an archive of problems. I used Timus for historical reasons. I guess the default choice now would be the CF problemset. Here are some points why Timus might be better:
On the other hand, CF has its advantages:
At the end of the day, solving problems on one of the platforms is more productive than debating which platform is better. If you want to try Timus — you are welcome. If you want to stick to CF — it is also a good option.
Are you enjoying England?
How is that relevant here?