>Sorting is a mostly "solved" problem in theory, but as new hardware emerges different aspects of implementations become more or less important (cache, memory, branch prediction)

This makes me wonder what other hardware tricks might be used for other popular algorithms such as ones used in graphs. I'm sure shortest path is also one of those algorithms that have been "solved" in theory but have a huge amount of research, but personally, what would be more interesting to hear about is something that isn't quite as easy. Something like linear programming with integer constraints or even something like vehicle routing or scheduling. To anyone studying those areas, is there anything you find particularly interesting?