artificial intelligence

Consider the two-player, turn-taking, zero-sum game for the game tree:

4. Suppose you were using a heuristics to decide on the expansion order of the states. What would be the perfect heuristics? That is, for each node, in which order should child nodes be expanded such that the - (alpha - beta) algorithm expands the smallest number of nodes? Write down the names of the all nodes in the order in which they should be expanded. For example, adjkelmbfnogpqchrsitu would be the normal left-to-right expansion.

5. The perfect heuristic as discussed in the previous question is not achievable in practice. Why? Despite that fact, what could be done to increase the amount of pruning that - (alpha - beta) search does?