String indexer

The app should group words from input string by first letter and sort them in lexicographical order. All groups that contains less than 2 words should be hidden. In every group words should be sorted by length in decreasing order. If two words have the same length compare them lexicographical.

Example: 
"care apple car break bread boost" -> [b=[boost, bread, break], c=[care, car]]

Class Indexer

Got two values - min counts of words with the same first letter and delimiter - string that separates words in sentence

Indexer has method makeIndexing that return needed result as a string