title: Find majority element when the values are unknown
body: <p>Suppose I have an array of elements.
  I cannot read the values of the elements. I can only compare any two elements from the array to know whether they are the same or not, but even then I don't get to know their actual values.</p>
  <p>Suppose this array has a majority of elements of the same value. I need to find and return any of the majority elements. How would I do it?</p>
  <p>We have to be be able to do it in a big thet.of n l0g n.</p>