title: Find max/min of vector of vectors
body: <p>What is the most efficient and standard (C++11/14) way to find the max/min item of vector of vectors?</p>
  
  <pre><code>std::vector&lt;std::vector&lt;double&gt;&gt; some_values{{5,0,8},{3,1,9}};
  </code></pre>
  
  <p>the wanted max element is <strong>9</strong></p>
  
  <p>the wanted min element is <strong>0</strong></p>