title: Merging two strings to one String without duplicate alphabets in ascending alphabetical order
body: <p>Suppose I have 2 strings:</p>
  
  <ul>
  <li>str1 = "bcdefghijkl"</li>
  <li>str2 = "ehikoz"</li>
  </ul>
  
  <p>I want to copy the elements of <code>str2</code> into <code>str1</code> such that the resulting <code>str1</code> = <code>"bcdefghikoz"</code>.</p>
  
  <p>For example,</p>
  
  <ul>
  <li>str1 = "aefghlowxyz", str2 = "delo", result = "adefghlowxy"   </li>
  <li>str1 = "befghklnqtz", str2 = "cehix", result = "bcefghiklnx"</li>
  </ul>
  
  <p>A few conditions are:
   - The elements should remain in alphabetical order
   - The size of string a should remain 11
   - If an alphabet of <code>str2</code> is not in <code>str1</code> already then it should replace the elements of <code>str1</code> in alphabetical order</p>