After passing one phone interview, I was invited for an onsite interview.

There were two guides who came to meet us candidates, but they were late by about 15-20 minutes.

I had two technical interview rounds.

The first round was okay. However, in the second round, one interviewer seemed very nervous, and the other was very tired; he frequently drifted off and required me to repeat what I had said. It was a very bad experience.

Verify whether a binary tree is a BST or not.