Choose words with no shared letters to cover the most letters
Given a list of lowercase words, pick a subset in which no letter appears twice across the chosen words, maximizing the number of distinct letters covered. Start with a correct backtracking search, then make it fast enough for lists of about ten thousand words by encoding words as bitmasks and reusing states. The round runs in stages, with an AI assistant available.
No answer yet. Write the first one; the best answer gets endorsed.