title: Boost Intrusive/binary search trees
body: <p>I'm looking for a binary search tree for a Voronoi tessellation algorithm (Fortune's algorithm; a darned non-trivial task in itself, methinks), so of course, I thought I'd have a look at Boost.</p>
  
  <p>Boost has the <code>Intrusive</code> header file, which seems to contain a wealth of BSTs (such as AVL, Splay trees, and Scapegoat trees - ha, I had to make sure of that name there!) and at first sight looked to be just what I needed.</p>
  
  <p><strong>1:</strong> Am I missing something or is there no way to directly access the root node of a tree?</p>
  
  <p><strong>2:</strong> Is an AVL tree appropriate for the Fortune algorithm beachline structure?</p>
  
  <p>Damn, I thought this was going to be easy.</p>
  
  <p><strong>Update:</strong> Perhaps it's better to state what I aim to achieve: I'd like to implement the parabola search that is part of the Fortune algorithm, the part where a new site is detected and we need to find the parabola directly overhead. I thought I would traverse the tree starting from the root, in order to find the correct arc.</p>