With an (average or constant) branching factor of b, and a search depth of d plies, the maximum number of leaf node
positions evaluated (when the move ordering is pessimal) is O(b*b*...*b) = O(b
d
) – the same as a simple minimax
search. If the move ordering for the search is optimal (meaning the best moves are always searched first), the number
of leaf node positions evaluated is about O(b*1*b*1*...*b) for odd depth and O(b*1*b*1*...*1) for even depth, or