Finding a problem

Searching the problem list by name or by meaning, the topic, difficulty and status filters, the sort control, and how the list you filtered becomes the one Next walks.

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/problems is the whole catalogue. It is a public page - you can read and filter it signed out, though two of the filters only mean something once we know who you are.

Reading a row#

Each row carries five things, in this order: your status, the number and title, its topics, its acceptance rate, and its difficulty. On a narrow screen topics and acceptance drop away; status, title and difficulty always stay, because difficulty is the column the list is actually read down.

The status column is a tick for solved and a dot for attempted-but-not-solved. Signed out it is blank - that is "we do not know", not "you have not solved it".

The acceptance rate#

The share of submissions on that problem that were accepted. It sits next to the difficulty label on purpose: a problem marked Hard that most people solve first try is a label worth doubting, and showing both lets you doubt it.

Searching#

The search box at the top matches a problem's title, its topics and the words of its statement - and, when you describe a problem rather than name it, its meaning. "Find the largest number in an array" finds Tallest Building, whose title shares none of those words.

Rows found only by meaning carry a Related tag, so you can tell them apart from rows that contain the words you typed. A row matched through its topic or its description says that too. When the search ran by meaning, a Revquix AI mark appears in the box; if that part of search is ever unavailable the box quietly falls back to words alone and the mark disappears with it.

/ jumps to the search box from anywhere on the page, and Esc clears it.

The filters#

  1. Topics - the chips under the search box. Pick one or several; several means a problem tagged with any of them. All topics clears them.

    Once a topic is picked, a switch named after it appears beside the other controls, such as Array only (Only these topics when you have picked several). Turn it on to hide problems that are also tagged with something else: Array alone is then the problems about arrays and nothing else, not every problem that touches one, and Array with Sorting is the problems about arrays, sorting or both. Topic pages have the same switch.

  2. Difficulty - Easy, Medium and Hard toggle independently, so Easy and Medium together is one click each.

  3. Status - All problems, Not solved, Attempted or Solved. This one only appears when you are signed in, because none of those questions has an answer otherwise.

  4. Sort - problem number, difficulty, acceptance, most attempted or newest, and Best match while you are searching. The arrow beside it flips the direction. Problems too new to have an acceptance rate go last whichever way acceptance is sorted.

  5. Random opens a random problem from the list you are currently looking at. Filter to unsolved mediums first and you get a random unsolved medium, which is almost always what people mean.

Everything you set is in the page address, so a filtered list is a link you can bookmark or send. Changing any filter takes you back to the first page, and Clear all puts the whole catalogue back.

The list you filtered is the list Next follows#

Open a problem from a filtered list and the arrows above the editor walk that list: Next after a Medium two-pointer problem, opened from "Medium, Two Pointers, Not solved", is the next unsolved Medium two-pointer problem. The same list is in the workspace's problem-list panel. See the solver.

Paging#

The count beside the controls is the whole filtered result, not the page. Your own account-wide solved count lives in the sidebar card instead, where it always describes the entire catalogue.

Browsing by topic#

Every problem carries one to five topics, the first being its primary one. The topic chips filter the list in place; the full taxonomy also sits at the foot of the list, grouped into four families - Data Structures, Algorithms, Techniques and Maths

  • and each is a real page at /problems/topic/<topic>.

Topic pages are worth using rather than being a filter in disguise: they are server-rendered, they link to each other, and they are the pages that turn up in a search engine. If you want to drill one idea - every sliding-window problem, in order - that is the page to bookmark.

The sidebar#

To the right of the list (below it on a phone) sit three cards:

  • Your practice - solved counts by difficulty, your streak, and a twelve-week activity strip. It is an invitation to sign in when you are not.
  • Browse by topic - the ten largest topics.
  • Not sure where to start? - a link to tracks, which is the honest answer to a long list of problems and no opinion about which to do next.

The full version of that first card, including every submission you have made, is your practice dashboard.

The solver

What happens when you open one.

Tracks

An ordered path instead of a filter.

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