title: Maximum number of red nodes in red black tree
body: <p>In <a href="http://en.wikipedia.org/wiki/Red%E2%80%93black_tree" rel="nofollow">a red-black tree</a> with <code>n</code> nodes, what is the maximum number of red nodes (assuming the root is black)?</p>
  
  <p>Is it <code>O(n)</code>?</p>