What can be the efficient approach to solve the 8 puzzle problem?

Question

The 8-puzzle is a square board with 9 positions, filled by 8 numbered tiles and one gap. At any point, a tile adjacent to the gap can be moved into the gap, creating a new gap p

Answer 1

Since the OP cannot post a picture, this is what he's talking about:

As far as solving this puzzle, goes, take a look at the iterative deepening depth-first search algorithm, as made relevant to the 8-puzzle problem by this page.