/**
 * @author 		Churong Zhang 
 * 			cxz173430
 * @date		December 12 2018
 * 			Dr. Raghavachari
 * 			This class is for Project 5
 * 			classes of MST
Implement Prim and Kruskal algorithms for minimum spanning trees that were
discussed in class.  Implement take 1 of Prim that uses a priority queue
of edges. 

Example Input: "5 6   1 2 3 1 4 5 4 5 9 1 5 6 2 5 7 2 3 5 ";
Example Output:
Algorithm: Prim with PriorityQueue<Edge>
The minimum weigth is 19
From 1 To 2
From 1 To 4
From 2 To 3
From 1 To 5
Time: 4 msec.
Memory: 2 MB / 243 MB.