public static void Main(string[] args)
{
Graph g = new Graph();
g.add_vertex('A', new Dictionary<char, int>() {{'B', 7}, {'C', 8}});
g.add_vertex('B', new Dictionary<char, int>() {{'A', 7}, {'F', 2}});
g.add_vertex('C', new Dictionary<char, int>() {{'A', 8}, {'F', 6}, {'G', 4}});
g.add_vertex('D', new Dictionary<char, int>() {{'F', 8}});
g.add_vertex('E', new Dictionary<char, int>() {{'H', 1}});
g.add_vertex('F', new Dictionary<char, int>() {{'B', 2}, {'C', 6}, {'D', 8}, {'G', 9}, {'H', 3}});
g.add_vertex('G', new Dictionary<char, int>() {{'C', 4}, {'F', 9}});
g.add_vertex('H', new Dictionary<char, int>() {{'E', 1}, {'F', 3}});
g.shortest_path('A', 'H').ForEach( x => Console.WriteLine(x) );
}