step 32 / 32 · 6 min
What the rounds are actually testing
A placement process is several different assessments wearing similar clothing. Knowing which one you are in changes what you should be doing.
The rounds
| Round | Testing |
|---|---|
| Online test | speed and accuracy on standard problems |
| DSA interview | problem solving, and thinking out loud |
| System design | trade offs, and whether you ask questions |
| Core subjects | did you understand, or memorise |
| Project discussion | can you explain your own decisions |
| Behavioural | how you work with people |
The DSA round
They are not marking the final code as heavily as candidates assume. They are marking the approach: do you clarify the input, state a brute force, notice the repeated work, choose a structure for a reason, and handle the edges.
Think out loud. A silent candidate who produces a correct answer scores below one who narrated a slightly worse approach, because the interviewer has no evidence of reasoning from the first.
The system design round
The most common failure is drawing a diagram immediately. The expected first five minutes are questions: what does it do, how many users, read or write heavy, how fresh must the data be, what happens if it is down.
Then estimate roughly, sketch something simple, and improve it as you identify bottlenecks. Name what each choice costs. "We add a cache, which means reads may be a minute stale, which is fine for a catalogue and not for a balance" is the sentence they are listening for.
The core subjects round
Questions are usually one layer deeper than the definition. Not "what is an index" but "why did adding one make writes slower". Not "what is a deadlock" but "how would you prevent one here".
Answers that name a mechanism beat answers that name a term.
The project discussion
The one candidates under prepare, and the easiest to do well in, because you have the information.
Be ready to say: what problem it solved, why you chose that approach, what you would do differently, what broke and how you found it, and what you would do if it had a hundred times the traffic.
If you cannot answer why you chose a technology, that reads as having followed a tutorial. "We used Postgres because the reporting needed joins" is a complete answer, and it is a short sentence.
Honesty
"I do not know, here is how I would find out" is a good answer. Bluffing is obvious to someone who knows the topic, and it costs more than the gap would have.
Preparing
Consistent short practice beats occasional long sessions. Do timed problems, because the pressure is part of what is being tested. Explain your solutions out loud to nobody, since the articulation is half the assessment. Prepare two projects properly rather than listing six.