title: Google dense_hash_map C++
body: <p>So, I'm trying to implement a map that will have probably around 20,000 String, String pairs in C++.  Is it worth it to use Google Dense Hash Map?  I will be mainly checking the map for the pair and inserting it if not found.  I wont be making any deletions or alterations to the pairs.  If I should use dense hash map, how do I?  There is not much information online but I know I need a hash function.</p>
  
  <p>EDIT: they are String to String pairs</p>