Once you've written your solution code out, the technical portion should be done.

The interview will now steer towards questions for the interviewer. Make sure that you have questions prepped, and try your best not to think about your performance.

At that point, whatever happened is out of your control, so be forward looking and keep your mind in the present with the interviewer. You'll come across as much more professional if you can maintain your composure, even if the interview didn't go exactly how you wanted.

I hope you've found this guide helpful. Remember that any coding challenge can be solved with the right approach, and the right mentality. Best of luck!