title: How to convert a vector<pair<int,int> > to multimap<int,int> efficiently?
body: <p><code>How to convert a multimap&lt;int,int&gt; to vector&lt;pair&lt;int,int&gt; &gt; efficiently</code></p>
  
  <p>EDIT:
  Sorry for the trouble I was actually looking for converting vector to map</p>