DSA Round

Practice a real DSA online assessment before the one that counts.

A timed coding round built to match the online assessments companies actually send you. You choose the format and the language, you solve against the clock, and at the end an AI reviewer explains not just what you got wrong, but where your time went and which problem you should have opened first.

4

Assessment formats

4

Languages

45–90

Minutes per round

4-problem full round · 90 minutes41:27

def longest_window(events, limit):

left, best, seen = 0, 0, {}

for right, e in enumerate(events):

seen[e] = seen.get(e, 0) + 1

...

Assessment formats

Four formats, matched to real hiring rounds.

Each format below copies the problem count, difficulty mix and time limit of an online assessment that companies genuinely run. Pick the one that matches the employers you are applying to.

0 min

Service company screen

2 problems

Easy

Medium

Two problems in 45 minutes: one easy, one medium. This is the first-filter format most service and consultancy employers use. The easy problem is meant to be cleared quickly, so the real test is whether you leave yourself enough time for the medium one.

0 min

Product company screen

2 problems

Medium

Medium

Two medium problems in 70 minutes, with no easy warm-up. Product companies usually skip the gentle opener, so both problems carry equal weight and your pacing decides whether you finish.

0 min

4-problem sprint

4 problems

Easy

Medium

Medium

Hard

Four problems in 70 minutes, rising from easy to hard. Most people do not finish all four, and that is deliberate. Choosing what to attempt and what to leave is part of what gets scored.

0 min

4-problem full round

4 problems

Easy

Medium

Medium

Hard

The same four problems as the sprint, with 90 minutes instead of 70. There is room to think properly, so the hard problem is judged on how well you solved it rather than whether you simply got it passing.

Solve inPythonJavaC++JavaScript
/ HOW IT WORKS

Build. Solve. Get coached.

Step 01

Build your round

Start by choosing the language you want to code in. Then pick one of the four assessment formats: two short screens of two problems, and two longer rounds of four. Each format sets its own time limit and difficulty mix, and each one is modelled on an online assessment that companies genuinely send out.

Step 02

Solve under the clock

You get a full-screen code editor, a countdown timer, and your list of problems down the side so you can move between them freely. Run your code against the visible test cases as often as you like while you work. When you submit a problem it is locked in, and a second set of hidden tests runs against it.

Step 03

Get coached, not just scored

When the round ends, an AI reviewer reads your code, your timings, and the order you worked through the problems. You get written feedback on each problem, plus a summary of how you spent your time across the whole round and what you should have done differently.

/ SCORING

Scored like a real reviewer.

Every round ends with an overall score, four sub-scores, per-problem coaching, and a time note. Here is how the score is built.

Correctness

40%

How many hidden tests your code passes, weighted by problem difficulty. Clearing the hard problem counts for more than clearing the easy one, and a brute-force answer that passes still scores below an efficient one.

Time management

25%

How you spent the minutes you were given, measured against the time limit of the format you chose. You are never judged against a fixed stopwatch, so a 45-minute screen and a 90-minute round are each assessed on their own terms.

Edge-case discipline

20%

Whether your code holds up on empty inputs, boundary values and off-by-one conditions. These are the cases that look fine on a quick read and then fail the hidden tests.

Code quality

15%

Naming, structure, and code you left behind but never used. Passing every test is the starting point rather than the finish line, so working code still gets feedback on how it reads to someone else.

/ WHY IT WORKS

Built like the rounds that reject people.

01

The order you answer in gets scored too

The round records when you opened each problem, how long you stayed on it, and whether you gave up and came back later. Most people lose an assessment by spending forty minutes on the wrong problem, so the review shows you where your minutes actually went and which order would have scored higher.

02

Hidden tests, exactly like the real assessment

The visible test cases are there for you to work against while you code. A second set of hidden tests runs only when you submit, and those results stay hidden until the round ends, so you cannot reverse-engineer the answer from the feedback.

03

You will not be handed the same problems twice

Every round excludes every problem you have seen in your last three rounds. Retaking a format gives you a genuinely new set, so your score reflects your ability rather than your memory.

04

Each format is scored on its own

Scores never mix between formats. A 45-minute two-problem screen and a 90-minute four-problem round test different skills, so each keeps its own history and its own progress chart. Improving at short screens will not inflate your full-round score.

05

Every problem is verified before you see it

Each problem ships with a reference solution that has been machine-run and confirmed to pass in your chosen language before that problem can be served. You will never lose time to a broken problem or a test case that cannot be satisfied.

06

The clock does not stop

When the time runs out, whatever you have is collected and scored, exactly as a real online assessment does. There is no pause button and no overtime, because there is not one on the day either.

Your first round sets your baseline.

From there, every round you run is measured against that first one. Your scores, your pacing and your edge-case discipline are all tracked over time, and each format keeps its own history so you can see exactly where you are improving and where you are not.

Start a round
/ ALSO ON PLAICER

Practice a mock technical interview like it's the real thing.

The DSA round tests whether you can solve problems correctly on your own under time pressure. The mock technical interview tests something different: whether you can explain your thinking out loud to someone who keeps asking why. Six stages, an AI interviewer that follows up on your answers, and a written report on how you reasoned rather than just what you produced.

Six stages covering technical questions, live coding, your own project, system design, code review and building with an AI assistant.

Run a single stage to drill one weakness, or stack several back-to-back and get one combined report for the whole sitting.

Scored on communication and depth under probing, not only on whether your code ran.

/ QUESTIONS

DSA round questions

What is a DSA online assessment?

It is the timed coding test most companies send you before anyone speaks to you. You get a small number of data-structures-and-algorithms problems, a fixed time limit, and hidden test cases you cannot see while you work. It is usually the first filter in the hiring process, and it is where most candidates are rejected.

How long is a round, and how many problems do I get?

There are four formats. Two short screens of two problems each, at 45 and 70 minutes. Two longer rounds of four problems, at 70 and 90 minutes. The four-problem rounds always run easy, medium, medium, hard, so the only thing you choose there is how much time you get.

Which programming languages can I use?

Python, Java, C++ and JavaScript. You pick your language when you build the round, and every problem has been verified to be solvable in the language you chose before it is served to you.

What are hidden tests?

Each problem comes with visible test cases you can run as often as you like while you code, plus a second set of hidden tests you never see. The hidden tests only run when you submit, and their results stay sealed until the round finishes. Real online assessments work exactly this way, which is why a solution that passes the examples can still fail the assessment.

How is my round scored?

Four measures make up one overall score. Correctness is 40% and is weighted by problem difficulty. Time management is 25% and is judged against the time budget of the format you picked, never an absolute stopwatch. Edge-case discipline is 20%. Code quality is 15%, covering naming, structure and code you left behind unused.

Do I need to finish every problem?

No, and on the tighter formats you probably will not. That is deliberate. Deciding which problem to attempt, which to leave, and when to give up on one and move to the next is part of what gets scored. The review tells you where your minutes went and which order would have scored higher.

Can I retake a round?

Yes, and you will not be handed the same problems again. Every round excludes every problem you have seen in your last three rounds, so a retake is a genuine retake rather than a memory test.

What happens when the timer runs out?

Whatever you have is collected and scored, exactly as a real online assessment does. There is no pause button and no overtime, because there is not one on the day either.

How is this different from practising on LeetCode?

Solving problems one at a time with no clock trains a different skill from sitting a timed assessment. Here you get the whole round: a fixed time budget across several problems, hidden tests, and no ability to look up the answer. You are also scored on time management and edge-case discipline, which is where most candidates actually lose the assessment.

Do my scores carry across the different formats?

No. Each format keeps its own history and its own progress chart, because a 45-minute two-problem screen and a 90-minute four-problem round test genuinely different skills. Getting better at short screens will not inflate your score on the longer rounds.