title: worst case- / best case keys for binary search?
body: <p>can someone please help me with this question? How am i supposed to proof the keys mathematically?</p>
  
  <p>Construct an arbitrary non-trivial array a that fulfills the pre-conditions for binary
  search. Construct keys <code>ka</code>, <code>kb</code> with</p>
  
  <pre><code>a) worst case lookup time
  b) best case lookup time
  </code></pre>
  
  <p>if used with binary search on a.</p>
  
  <p>How many recursion steps does it take to find <code>ka</code>, <code>kb</code>?</p>