c-index_-randomaccessindextype-partition_isorderedbefore_"><div class="p">
    <p>Re-order the given <code>range</code> of elements in <code>self</code> and return
a pivot index <em>p</em>.</p>

<p><strong>Postcondition:</strong> for all <em>i</em> in <code>range.startIndex..&lt;</code><em>p</em>, and <em>j</em>
  in <em>p</em><code>..&lt;range.endIndex</code>, <code>less(self[</code><em>i</em><code>],
  self[</code><em>j</em><code>]) &amp;&amp; !less(self[</code><em>j</em><code>], self[</code><em>p</em><co