图（二图）与顶点

Question

     try {
         in = new FileInputStream(file);
         reader = new BufferedReader(new InputStreamReader(in));

         int i, ii, size = Integer.parseInt(reader.readLine());
         nodes = new String[size];
         matrix = new int[size][size];
         for (i = 0; i < size; i++) {
             String node = reader.readLine();
             if (node == null) throw new IllegalStateException("Insufficient nodes");
             nodes[i] = node;

             matrix[i][i] = -1;
             for (ii = 0; ii < size; ii++) {
                 matrix[i][ii] = -1;
                 matrix[ii][i] = -1;
             }
         }
         int fi, ti;
         String from, to;
         while ((from = reader.readLine()) != null && (to = reader.readLine()) != null) {
             fi = indexOfOrThrow(nodes, from);
             ti = indexOfOrThrow(nodes, to);

             matrix[fi][ti] = 1;
             // TODO: If not bidirectional then remove next line
             matrix[ti][fi] = 1;
         }
     } catch (Throwable tr) {
         tr.printStackTrace();
         return;
     } finally {
         try {
             if (reader != null) reader.close();
             if (in != null) in.close();
         } catch (Throwable ignored) {
         }
     }
 }
 private static int indexOfOrThrow(String[] nodes, String node) {
     int i = indexOf(nodes, node);
     if (i < 0) throw new IllegalArgumentException("No entry found for: " + node);
     return i;
 }

 private static int indexOf(String[] nodes, String node) {
     if (node == null) {
         for (int i = nodes.length - 1; i >= 0; i--) {
             if (nodes[i] == null) return i;
         }
     } else {
         for (int i = nodes.length - 1; i >= 0; i--) {
             if (node.equals(nodes[i])) return i;
         }
     }
     return -1;
 }

}

Answer 1

10

a

B C

A E

A H

B C

H E

H I

I J