title: find element with max value from std::map
body: <p>I'm trying to get the element with max value from std::map, </p>
  
  <pre><code>int main() {
      map&lt;int, int&gt; m;
      m[1] = 100;
      m[2] = -1;
  
      auto x = std::max_element(m.begin(), m.end(), m.value_comp());
  
      cout &lt;&lt; x-&gt;first &lt;&lt; " : " &lt;&lt; x-&gt;second &lt;&lt; endl;
  }
  </code></pre>
  
  <p>why it prints the second element <code>2 : -1</code> ?</p>