I think it's better to not repeat too much from previous guesses. I don't think my greedy algorithm is optimal, and also there are multiple ways to define "optimal". For instance, you might optimize average number of moves, or try to lower the upper bound for all possible words.
Oh I misunderstood the comment I was replying to. Sometimes it is better to repeat letters, because it's a balance between discovering letters and figuring out the order.
