title: Find the most popular element in int[] array
body: <pre><code>int[] a = new int[10]{1,2,3,4,5,6,7,7,7,7};
  </code></pre>
  
  <p>how can I write a method and return 7?</p>
  
  <p>I want to keep it native without the help of lists, maps or other helpers.
  Only arrays[].</p>