This problem reminded me of the Quipu problem of SRM 155, except I was in div 2 at the time.
For this problem, find the last dash on each line, figure out how far from the right side it is, add and multiply by 10. Then do the opposite.
For some reason I felt that reconstructing it "backwards" (bottom-to-top and right-to-left) was easier, but somehow I passed all examples.
I got kicked off right after opening the problem so I lost a couple minutes, grr.
This problem made my head hurt. BOB. The write-up was pretty convincing, though. Any BOB that is a supervisor can be "The" BOB who supervises everyone. (Except, I suppose, another BOB, because, er, what if that BOB is a supervisor too. Hmm, this is why my head hurt.)
Needless to say, I didn't get it.
I thought a few minutes about this one, and saw that it was too big for bruteforce. Thought that it might be a DP-ish problem, but it seemed too graphy for that. Ultimately I didn't get it, but the posted solutions look pretty straightforward and the writeup was crystal clear (except for the time bounds; F-W does seem too slow.)