The interviewer was multitasking while interviewing me, and he was doing it effortlessly.

He began by saying it would be a 1-hour interview, with the first 45 minutes for DSA and the last 15 minutes for HR questions. He then began without asking for an introduction and pasted the question to the doc.

I was able to come up with a solution within the allotted time, so I briefly explained it to him. He asked me to code it up after clarifying and understanding my approach.

After I was done, he gave another follow-up, to which I gave multiple approaches, but not the one he expected. However, he appreciated that I tried approaching it in multiple ways.

He then asked some common HR questions during the last 15 minutes, and the interview ended successfully.

Given an undirected connected graph, Alice and Bob start from different nodes A and B and want to reach a destination node D.

If they travel separate edges, count them as separate. If they meet at some node and travel the same edge together, count it as a single edge.

Find the minimum number of total edges traveled by Alice and Bob to reach D.