title: Heap in Dijkstra algorithm
body: <p>can someone explain whats the importance of <strong><em>HeapDesc</em> in ShaneSaunders Dijkstra algorithm</strong> and how it is used here? 
  In general i know how Dijkstra algorithm works. But, i din't get the heap part in implementation.</p>
  
  <p>Its a big code. hence am posting a link if u want to have a look at it. </p>
  
  <p>Here go's <a href="http://www.cosc.canterbury.ac.nz/research/RG/alg/dijkstra.cpp" rel="nofollow">http://www.cosc.canterbury.ac.nz/research/RG/alg/dijkstra.cpp</a></p>