 graphs.</span></div>
<div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;<span class="comment">// TODO(user): add depth-first-search based biconnectivity for directed graphs.</span></div>
<div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160; </div>
<div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;<span class="preprocessor">#ifndef OR_TOOLS_GRAPH_CONNECTIVITY_H_</span></div>
<div class="line"><a name="l00021"></a><span class="li