8puzzle

这是一个简单的益智游戏，试图解决与步骤最少的问题！

The 8 number puzzle is a simple game which consists of eight sliding tiles, numbered by digits from 1 to 8, placed in a 3x3 squared board of nine cells. One of the cells is always empty, and any adjacent (horizontally and vertically) tile can be moved into the empty cell. The objective of configuration and end up in a configuration which the tiles are placed in ascending number order and the empty cell is in the right bottom of board.

We provide more than 400 levels, 3 difficulties. Try to solve the problem with fewest steps!