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How the coding workbench works

A problem workspace built for focus.

DSA problems with real test cases in thirteen languages, in a workspace you can shape to how you think — and a timer that only counts the minutes you were actually there.

Languages

13

Editor

Monaco, 5 themes

Timers

Stopwatch · Countdown · Pomodoro

Verdicts

Hidden tests, runtime & memory

What are CodeKairo's coding challenges?

More than 1,500 DSA problems — roughly 490 easy, 800 medium and 300 hard — judged on hidden tests in any of 13 languages, each with a typed signature, starter code per language and visible sample cases; most carry hints and an editorial. They are solved in one workbench: description, editor and results in resizable panels — standard, mirrored or three-column — with a Monaco editor in five themes. Run checks the samples and your own cases; Submit records one verdict with runtime and memory; a timer pauses when you leave the tab. Problems can be read without an account; running code needs a free one, and solving is unlimited on every plan. This page is about the workbench; the problems themselves are at /challenges.

01How it works

From the statement to a verdict, on one screen.

Who it is for

Anyone preparing for a coding round who wants the practice to feel like the round: the workspace arranged the way they read, the edge case an interviewer will ask about one click away, and a clock that counts the minutes spent solving rather than the minutes a tab was open.

  • 01

    Pick a problem and a language

    Filter by difficulty, status and topic, from the catalogue or the workbench's own list. The editor opens with the typed starter signature in whichever of the 13 languages you choose, and drafts autosave per problem and per language.

  • 02

    Arrange the workspace

    Description, editor and results in resizable panels — standard, mirrored or three-column — and the arrangement is remembered. Five editor themes; the editorial, the hints and every past submission with its code sit in tabs.

  • 03

    Run, then Submit

    Run executes the visible sample cases and any you added — the empty array, the single element — with every output beside the expected one, as often as you like and never recorded. Submit runs the hidden tests and records one verdict — Accepted, Wrong Answer, Time Limit Exceeded or Runtime Error — with cases passed, runtime and memory.

  • 04

    Keep an honest clock

    A stopwatch, countdown or Pomodoro in the header, paused when you switch tabs and still where you left it after a reload. First-run and first-submit times are kept per problem, and an accepted solve moves your rating.

02The layout

Everything on one screen. Nothing in the way.

codekairo/problems/maximum-subarray
FIG. 01Standard layout. The header carries Run/Submit, the timer, layout presets and settings; nothing else competes with the code.
  • 01

    Three panels, your proportions

    Description, editor and results in resizable panels. Drag the dividers; the split is remembered.

  • 02

    Standard, mirrored or three-column

    Put the editor on the left if you read that way. Or stack everything vertically on a narrow screen.

  • 03

    Editor themes that match the app

    CodeKairo, VS Dark, Monokai, GitHub Dark, One Dark. The default follows your light/dark choice.

  • 04

    Editorial, hints and history in tabs

    Read the editorial when you're done (or stuck), open hints one at a time, and revisit every past submission with its code.

03Run vs Submit

Run is for you. Submit is for the record.

Run executes your code against the visible sample cases and anything you added. You see every case, your output, the expected output, and how long it took. Run as often as you like — nothing is recorded.

Submit runs the hidden tests. You get one verdict — Accepted, Wrong Answer, Time Limit Exceeded, Runtime Error — with the number of cases passed, runtime and memory. Accepted moves your rating; everything is kept in the problem's submission history with the exact code you sent.

codekairo/problems/maximum-subarray
FIG. 02Run first: every sample case with your output beside the expected one. Then Submit: hidden tests, one verdict, runtime and memory.
04Timers

A clock that tells the truth.

Most practice timers measure how long a tab was open. Ours measures how long you were solving. It pauses when you leave, persists when you reload, and shows up in the header so you never have to go looking for it.

Your first-run and first-submit times are kept per problem, and the personal best is on your dashboard.

  • 01

    Stopwatch

    Counts up from zero. The honest default.

  • 02

    Countdown

    Set a budget — 15 minutes is the usual for an easy — and see it drain.

  • 03

    Pomodoro

    Work/break cycles with a sound when the phase flips, if you want it.

  • 04

    Auto-pause

    Switch tabs and the clock stops. Come back and it resumes. Reload and it's still where you left it.

05Test cases

Sample cases to start. Yours to finish.

Every problem ships with visible sample cases. When you think of the edge case the samples don't cover — the empty array, the single element, the negative numbers — add it. Custom cases live with the problem and run with every Run.

It's the habit interviewers are actually checking for, so we made it one click.

codekairo/problems/maximum-subarray
FIG. 03Case 3 fails, line 4 gets fixed, the run goes green. Custom cases plug into exactly this loop.
06Finding problems

Filter by difficulty, status and topic — from anywhere.

codekairo/challenges
FIG. 04Difficulty, status and search narrowing the list — the same filters live inside the workbench's problem list.
07Questions

Do runs count against anything?

What happens on a wrong submission?

Can I bring my own test cases?

Is my draft saved?

Open a problem. The clock starts when you do.

Thirteen languages, hidden tests, a timer that doesn't lie.

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How the coding workbench works

Solve DSA problems judged by hidden tests in 13 languages, in a workbench with custom tests, a timer that pauses when you leave and full submission history.

What are CodeKairo's coding challenges?

More than 1,500 DSA problems — roughly 490 easy, 800 medium and 300 hard — judged on hidden tests in any of 13 languages, each with a typed signature, starter code per language and visible sample cases; most carry hints and an editorial. They are solved in one workbench: description, editor and results in resizable panels — standard, mirrored or three-column — with a Monaco editor in five themes. Run checks the samples and your own cases; Submit records one verdict with runtime and memory; a timer pauses when you leave the tab. Problems can be read without an account; running code needs a free one, and solving is unlimited on every plan.

How it works

  1. Pick a problem and a language. Filter by difficulty, status and topic, from the catalogue or the workbench's own list. The editor opens with the typed starter signature in whichever of the 13 languages you choose, and drafts autosave per problem and per language.
  2. Arrange the workspace. Description, editor and results in resizable panels — standard, mirrored or three-column — and the arrangement is remembered. Five editor themes; the editorial, the hints and every past submission with its code sit in tabs.
  3. Run, then Submit. Run executes the visible sample cases and any you added — the empty array, the single element — with every output beside the expected one, as often as you like and never recorded. Submit runs the hidden tests and records one verdict — Accepted, Wrong Answer, Time Limit Exceeded or Runtime Error — with cases passed, runtime and memory.
  4. Keep an honest clock. A stopwatch, countdown or Pomodoro in the header, paused when you switch tabs and still where you left it after a reload. First-run and first-submit times are kept per problem, and an accepted solve moves your rating.

Who it is for

Anyone preparing for a coding round who wants the practice to feel like the round: the workspace arranged the way they read, the edge case an interviewer will ask about one click away, and a clock that counts the minutes spent solving rather than the minutes a tab was open.

Frequently asked questions

Do runs count against anything?
No. Run as often as you like against sample and custom cases. Only Submit produces a verdict that touches your rating and history.
What happens on a wrong submission?
You get the verdict (Wrong Answer, Time Limit, Runtime Error…) with how many hidden cases passed, runtime and memory. It's recorded in your history like any other attempt.
Can I bring my own test cases?
Yes — add input/expected pairs in the Testcase panel. They're saved per problem in your browser and included in every Run.
Is my draft saved?
Drafts autosave per problem and per language, and timer state is persisted, so closing the tab mid-attempt costs you nothing.