Initial phone call with a recruiter provided general information about Google and the role in question, followed by a coding interview.

I failed the coding interview due to a misunderstanding with the interviewer. The question was simple (implement a stairway step counter), but the interviewer gave very vague instructions and didn't seem interested in seeing me succeed.

My impression is that such interviews are down to luck. You may be well prepared, but if the interviewer is biased or has poor communication skills, then it's difficult to pass.

Implement a stairway step counter in the programming language of your choice.