// The following statements should be included in your main() method,
// in the order as specified.

  Graph g1u = new Graph("g1.txt");  // undirected graph
  Graph g1d = new Graph("g1.txt", "d");  // directed graph

  Graph g2d = new Graph("g2.txt", "d");  // directed graph

  Graph g3u = new Graph("g3.txt");  // undirected graph
  Graph g4u = new Graph("g4.txt");  // undirected graph

 
// test numOfPaths() for undirected graph
  System.out.println("test numOfPath() for g1u");
  g1u.numOfPaths(1);
  g1u.numOfPaths(3);

// test numOfPaths() for directed graph
  System.out.println("test numOfPath() for g1d");
  g1d.numOfPaths(1);
  g1d.numOfPaths(3);

// test dfs() for undirected graph
  if (g1u.dfs(1, 7))
    System.out.println("g1u.dfs(1, 7) is true");
  else
    System.out.println("g1u.dfs(1, 7) is false");

  if (g1u.dfs(2, 5))
    System.out.println("g1u.dfs(2, 5) is true");
  else
    System.out.println("g1u.dfs(2, 5) is false");

// test dfs() for directed graph
  if (g1d.dfs(1, 7))
    System.out.println("g1d.dfs(1, 7) is true");
  else
    System.out.println("g1d.dfs(1, 7) is false");

  if (g1d.dfs(2, 5))
    System.out.println("g1d.dfs(2, 5) is true");
  else
    System.out.println("g1d.dfs(2, 5) is false");

// test shortestPath() for directed graph
  System.out.println("a shortest path from 1 to 9 in g2d:");
  g2d.shortestPath(1, 9);
  System.out.println("a shortest path from 4 to 1 in g2d:");
  g2d.shortestPath(4, 1);

// test EulerPath() for extra credit:
//   g3u.EulerPath();
//   g4u.EulerPath();