find subtree from binary tree
<p>See below binary tree.
And see implementation of this algo here: <a href="http://msdn.microsoft.com/en-us/library/ms379572(v=vs.80).aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/ms379572(v=vs.80).aspx</a></p>

<pre><code>                       1                           level 0
                2              3                   level 1
            4    5   6    7        level 2
       8       9  10   11  12  13   14 15          level 3
</code></pre>

<p>My question is: How do I discover subtree from this tree based on the level? Lets say I want to discover two leveled subtree from 15 numbered node. Then result should be </p>

<pre><code>          3
      6       7
12     13     14     15
</code></pre>

<p>If I search 3 leveled tree then it should be returned me above described full tree from 1 to 15.</p>

<p>Give me suggest for any code or algorithm or function which should be resolve this problem?</p>
