id = ID(),
                           InverseID inv = InverseID())
</pre>Constructor.
  <pre>
template &lt;class ElementIterator&gt;
void disjoint_sets_with_storage::
  normalize_sets(ElementIterator first, ElementIterator last)
</pre>This rearranges the representatives such that the representative of
each set is the element with the smallest ID.<br>
  Postcondition: <tt>v &gt;= parent[v]</tt><br>
  Precondition: the disjoint sets structure must be compressed.<br>
  <hr>

  <h2><a name="sec:representative-w