Perché sta cosa? Boh,vabbhè.
Mi viene in mente una cosa del genere:
codice:
<?xml version="1.0" encoding="UTF-8"?>
<graph>
  <rows>numero_righe</rows>
  <cols>numero colonne</cols>
  <data>
    <node id="0" ...>
      <connected_node>id_nod_h</connected_node>
      <connected_node>id_nod_j</connected_node>
      <connected_node>id_nod_k</connected_node>
    </node>
    <node id="1" ...>
      <connected_node>id_nod_h</connected_node>
      <connected_node>id_nod_j</connected_node>
      <connected_node>id_nod_k</connected_node>
    </node>
    ...
    ...
    <node id="numero_colonne - 1" ...>
      <connected_node>id_nod_h</connected_node>
      <connected_node>id_nod_j</connected_node>
      <connected_node>id_nod_k</connected_node>
    </node>
    ...
    ...
    <node id="numero_colonne x numero_righe - 1" ...>
      <connected_node>id_nod_h</connected_node>
      <connected_node>id_nod_j</connected_node>
      <connected_node>id_nod_k</connected_node>
    </node>
  </data>
</graph>
con spreco di spazio.