1. Strongly Connected Directed Graph (25 pts) A directed graph is strongly connected if every vertex is reachable from every other vertex in the graph. (Note that reachablility is via a path that could have one or more edges.) You are given an adjacency linked lists representation of a directed graph. Complete the implementation below to tell if a directed graph is strongly connected. Do not worry about the efficiency of your implementation. You may add other helper methods (with full implementation) as needed public class DirectedGraph f class Edge int vnum; I/ vertex number of neighbor Edge next; I/ pointer to next neighbor Edge (int v, Edge ptr) vnum-v; next-ptr;) // number of vertices int ni Edge] adjLists; 1 adjacency linked lists // define additional fields as necessary // returns true if this graph is strongly connected, false otherwise public boolean isStronglyConnected) // COMPLETE THIS METHOD