What is the time complexity, as a function of the number n of vertices and m of edges, of the following network operations if the network in question is stored in adjacency list format?
a) Calculating the mean degree.
b) Calculating the median degree.
c) Calculating the air-travel route between two airports that has the shortest total flying time, assuming the flying time of each individual flight is known.
d) Calculating the minimum number of routers that would have to fail to disconnect two given routers on the Internet.