title: better way of counting unique item
body: <p>I just find a way to count that number of unique items in a vector. This is my most naïve approach.</p>
  
  <pre><code>std::vector&lt;Items&gt; v;
  
  // some other work
  std::vector&lt;Items&gt; unique_Count;
  unique_Count.clear();
  std::unique_copy(v.begin, v.end(), std::back_inserter(unique_Count);
  int uniqueCount = unique_Count.size();
  </code></pre>
  
  <p>Is this the only with or this there a better way in the standard library? </p>