Professor gaedel has written a program that he claims implements dijkstra’s algorithm. the program produces v. d and v.π for each vertex v  v . give o(v+e)- time algorithm to check the output of the professor’s program. it should determine whether the d and π attributes match those of some shortest-paths tree. you may assume that all edge weights are nonnegative.

1. which of the following statements are true about routers and routing on the internet. choose two answers. a. protocols ensure that a single path between two computers is established before sending packets over it. b. routers are hierarchical and the "root" router is responsible for communicating to sub-routers the best paths for them to route internet traffic. c. a packet traveling between two computers on the internet may be rerouted many times along the way or even lost or "dropped". d. routers act independently and route packets as they see fit.