>&#160;  <span class="comment">// open list and closed list</span></div>
<div class="line"><a name="l00054"></a><span class="lineno">   54</span>&#160;  std::priority_queue&lt;Node, std::vector&lt;Node&gt;, Node::compare_cost&gt; open_list;</div>
<div class="line"><a name="l00055"></a><span class="lineno">   55</span>&#160;  std::unordered_map&lt;int, Node&gt; closed_list;</div>
<div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160; </div>
<div class="line"><a name="l00057"></a><span