<p>Given a sorted (increasing order) array with unique integer elements, write an algo&shy;rithm to create a binary search tree with minimal height.</p>

<p><strong>Example:</strong></p>

<pre>
Given sorted array: [-10,-3,0,5,9],

One possible answer is: [0,-3,9,-10,null,5]，which represents the following tree: 

          0 
         / \ 
       -3   9 
       /   / 
     -10  5 
</pre>