Ooh, interesting! I ended up making a framework to test different strategies. The minimax strategy is the most similar to yours, but it orders guesses by the

Ooh, interesting! I ended up making a framework to test different strategies. The minimax strategy is the most similar to yours, but it orders guesses by the maximum number of answer counts, and doesn't check any of the sub-trees. It still has a maximum guess length of 5, but has a slightly worse average at 3.81 guesses. Edit: How often do you need to evaluate sub-trees as a tie-breaker? I re-implemented your strategy of selecting the guess that minimizes the sum of the squares of the counts, but didn't include the evaluation of sub-trees. That was enough to reproduce your 3.67 average, (`{2: 23, 3: 802, 4:1416, 5:74}`), without the sub-tree recursion.