Airbnb Software Developer interview questions

I was referred to Airbnb through a friend, so I got an interview. It was a phone call with a technical person. The senior engineer asked me a question which I couldn't find a correct answer to in 30 minutes. He was cooperative, and he gave me a hint, but I still couldn't solve the problem.

Interviewers are generally unknowledgable of the questions they are asking (they are pulling it from an internal database). Wasted time trying to convince the interviewers of the algorithms when what I came up with was different than what the official solution is. (eg trying to convince the interviewer that DFS approach works on topological sort) They require complete/functional code, yet they don't provide a proper input to test from (one interviewer presented a 500 line file cut-pasted and wanted to get it into coderpad). They are not interested in how you think/approach to the problem, only if you can get the final answer or not.