   binary search tree.
    </p>
<p>
      A binary search tree is said to be weight balanced if half the nodes are on
      the left of the root, and half on the right. An a-height-balanced tree is defined
      with defined with the following equation:
    </p>
<p>
      <span class="bold"><strong><span class="emphasis"><em>height(tree) &lt;= log1/a(tree.size())</em></span></strong></span>
    </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
   