URGENT submission for JAVA task

1. Improve your implementation of Dijkstra's algorithm by using a priority queue. Note that for Dijkstra's algorithm, we need to find items in the priority queue and update their priorities (the decreaseKey operation). We would like to find items in constant time (and then logarithmic time for changing the priority). There are various ways to do this, including keeping a back-pointer from each vertex to its entry in the priority queue. 2. Extend MyGraph with a method for computing minimum spanning trees using one of the efficient algorithms discussed in class. Also write a driver program that reads in a graph and prints a minimum spanning tree. This driver will be much like FindPaths, but make a separate file and do not prompt the user for vertices or have a loop -- just print one minimum spanning tree. Explain in your write-up the format of what you print. 3. In write-up, describe what you did for #1 and #2.