Round 02 of 5 · free guide

The coding round: working code, under a timer, against hidden tests

One to three problems, judged automatically against test cases you cannot see. Partial credit is normal, and a solution that works on the example and fails on an empty input scores almost nothing.

What the round looks like

Usually Python, Java or C++ in a browser editor with no autocomplete and no internet. Between thirty and ninety minutes. Your code is compiled and run, not read by a human.

Where it goes wrong. Most students fail this round on edge cases rather than on approach. An empty input, a single element, all-equal elements, or a value that overflows an int — those four account for a great deal of lost marks.

How to prepare, in this order

The order matters more than the hours.

Read the constraints first: they tell you the intended complexity before you write anything

Learn the six patterns that cover most screening questions — two pointers, sliding window, hashing, prefix sums, binary search, memoised recursion

Write the brute force if you are stuck. A working slow answer beats an unfinished fast one

Test the empty case and the single-element case before you submit, every time

Do this now, for nothing

The free thing that helps with this round.

No account, no email. If it turns out you are already strong here, you have saved yourself the time you were about to spend on it.

Inside the platform, for this round

What being measured adds

  • Real execution against hidden test cases, in Python, Java and C++
  • A recorded step-through of your run, so you can see which line broke the logic
  • Plagiarism comparison across the batch, so a shared solution shows up as one

Tracks: DSA (23 modules), Python (20 modules) and Java (27 modules)

Round 02 — Coding. The free thing for this round takes a few minutes. Read the free Python course