Problems
The problem list is /problems/. Every filter is kept in the query string, so a filtered list is a link you can paste to someone else.

| Control | Parameter |
|---|---|
| Search problems, and full text search | search, full_text=1 |
| Status, relative to you | status=all|solved|attempted|unsolved |
| Hide solved problems, which wins over Status | hide_solved=1 |
| Category, the problem group | category=<group> |
| Types, repeatable, and showing them in the table | type=<name>, show_types=1 |
| Points, a minimum and a maximum | point_start, point_end |
| Solved by, repeatable, and narrowed to what you have not done | solved_by=<username>, not_by_me=1 |
| Author | author=<username> |
| Contest, repeatable, and sectioned by contest in contest order | contest=<key>, group_by_contest=1 |
| Has editorial | has_public_editorial=1 |
Sort by code, name, points, ac_rate, user_count or date | order=<field>, - for descending |
Clicking a column header also sorts by group, solved state, type and editorial. Reset clears everything except the sort and Show problem types.
A practice list is Solved by plus and not by me:
/problems/?solved_by=alice¬_by_me=1&order=-points/user/<user>/solved has the same thing from the other side, with a Compare with me toggle at ?compare=1.
On a problem page
The info box shows Solvers, Attempts, AC rate and the fastest recorded time. Show contests lists the contests the problem appeared in; it starts collapsed because a contest name can give the technique away, and your choice is remembered in the browser. The Editorial tab asks before it opens, with a "Don't ask me again" checkbox; a direct link to /problem/<code>/editorial is not intercepted.
/problem/<code>/rank/ is the leaderboard for one problem, with a By language panel giving each language's accepted count, AC rate and best time.
Getting around
Ctrl+K, Cmd+K, or / when you are not typing in a field opens the command palette, which searches problems, contests, users and organisations at once, remembers what you opened recently, and carries the four main lists, Search all problems, Random problem and Toggle dark mode.
/problems/random/ reads the category, types, point range, editorial switch and status filter from the page you clicked it on, and is not available inside a contest. /users/ jumps to the page of the ranking a person is on; unlisted users are not found.