Had one phone interview and was called for an on-site interview after that.

There were seven 1:1 interviews that day.

Most of the interviews were basic communication/networking/software and resume based.

The people who took my interview were very nice and it was a good experience for me - my first on-site interview.

It's been over a month now and haven't heard back.

Tried contacting HR (via email and phone) and was told they'll get back after asking the main recruiter for the group and again haven't heard back since then.

Communication with HR has been quite bad.

The least they could do is inform me about the status, even if it is a reject.

You have seven stones and a weighing scale. Six of the stones are equal in weight and one is lighter.

How will you figure out which one is lighter? What is the minimum number of tries required to do so?