Hello, Codeforces!
Only a couple of days remain until 2025. To wrap up the year, I'm bringing an update — I hope you'll find it useful.
Now, you can automatically find and add random problems for your mashup based on a range of criteria and restrictions. The problems are sourced from the archive, and unusual problems are automatically excluded.
So, click the "Add random problems" link under the problem list and proceed to the addition form.
Here's what you can do:
- Exclude problems that registered mashup participants have solved/attempted/authored (a problem will be excluded if at least one registered participant is familiar with it),
- If the mashup belongs to a group (e.g., your training group), exclude all problems from other contests in that group,
- Exclude problems with subtasks — such problems are often interconnected or reference each other,
- Simply specify a list of handles or user lists for whom familiar problems should be excluded,
- And finally, the most advanced option: in the "Problem Requirements" field, you can specify requirements for the problems to be added in a special format.
The "Problem Requirements" field describes the number and properties of the problems you want to find. By clicking the question mark icon, you'll see the following explanatory text.
Enter one or more lines. Each line specifies requirements for a single problem. A line must start with the Latin letter p
, followed by a space, and then additional parameters can be specified:
- Short problem name (its letter in the contest);
- Problem difficulty requirements (e.g.,
ratings:1000-1200
,ratings:2000
,ratings:3000-
, orratings:-1000
: leaving the number on the left or right of the hyphen empty means the corresponding boundary is not set); - Tags (use
tags:
and provide a comma-separated list of tags, e.g.,tags:dp, binary search, brute force
): a problem containing at least one tag from the list will be selected.
Examples of requirement lines:
"p"
: any problem, the letter in the contest will be assigned automatically;"p F"
: any problem assigned the letterF
;"p ratings:2000-2400"
: a problem with a difficulty level between 2000 and 2400, with the contest letter assigned automatically;"p D ratings:-1200 tags:greedy,dp"
: a problem with a difficulty level of no more than 1200, containing the tagdp
orgreedy
(or both), assigned the letterD
.
When you click the "Find Problems" button, you'll be presented with a list of problems to add. You can press the button repeatedly to generate different lists. In this list, you can mark the problems you like and finally add them to your mashup.
Note that next to the "Find Problems" button, after pressing it, additional statistics will be displayed. These can help you navigate the ratings of available problems under the specified restrictions.
I hope this makes finding problems for your training sessions and competitions easier.