HDU-3567 Eight II
Eight II (HDU - 3567) 题面 Eight-puzzle, which is also called “Nine grids”, comes from an old game. In this game, you are given a 3 by 3 board and 8 tiles. The tiles are numbered from 1 to 8 and each covers a grid. As you see, there is a blank grid which can be represented as an ‘X’. Tiles in grids having a common edge with the blank grid can be moved into that blank grid. This operation leads to an exchange of ‘X’ with one tile. ...