Letter Coverage

The letter/word coverage problem is the problem of finding the minimum number of words from the five-letter-words set (see Five Letter Words) to cover X letters of the alphabet.

The problem has a couple of variations: we might provide a set of letters, and search for the smallest number of words that can cover those particular letters. Or we might give an integer N <= 26, and search for the smallest number of words that can cover the first N letters of the alphabet.

We may also wish to restrict our search to the first M words of the 5757 total five letter words.