title: Error when pushing to vector of vectors
body: <p>I have a pointer to vector of vectors thats defined as this,</p>
  
  <p><code>vector&lt; vector&lt;Edge*&gt; &gt;* adj;</code></p>
  
  <p>and initilized,</p>
  
  <p><code>adj = new vector&lt; vector&lt;Edge*&gt; &gt;(v, vector&lt;Edge*&gt;());</code></p>
  
  <p>When I push back to this vector of vectors,</p>
  
  <pre><code>Edge* e = new Edge(v, w);
  adj[u].push_back(e);
  </code></pre>
  
  <p>I get an error,</p>
  
  <pre><code>prog.cpp:27:20: error: no matching function for call to ‘std::vector&lt;std::vector&lt;Edge*&gt; &gt;::push_back(Edge*&amp;)’
    adj[u].push_back(e);
                  ^
  </code></pre>
  
  <p>I dont understand whats wrong with this, I'm using it correctly right?</p>