Twenty-minute check

Not a real format: a quick read on where to start

One easy problem and one medium. The result tells you which difficulty to practice first.

• The clock does not pause. It starts when you press Start and keeps running if you close the tab. At zero, whatever is in the editor is submitted.
• Most tests are hidden. Running your code shows 2 sample tests in full. For the rest you see how many passed.
• Partial credit counts. Each problem is worth the same, and scores the share of its tests you pass.
• There is no interviewer. No hints and nobody to ask. Move between problems in any order.

This needs a real keyboard. Open it on a laptop or desktop.