I'm trying to understand the upper bound complexity for a Rush Hour game puzzle. I'm dealing with a 9x9
board, with 22
vehicles, including trucks (3 grids long) and cars (2 grids long).
By my logic, given the fact that a car can move 8 times
over a 9x9
board in one direction, the calculation would be 8^22
, which results in 7.34e+19
. This implies that the upper bound is 7.34e+19
different states for this puzzle.
It seems too excessive to me, for I want to calculate how close my algorithm to a solution is, given the number of iterated board states. Even supposing that all vehicles are trucks and therefore could only move 7
times seems too large.
Is my upper bound overestimated? Perhaps I should consider that the amount of movable space is the only space not occupied by a vehicle.