Sliding Tile Puzzle

Sliding puzzle is a simple and fun game. All you have to do is rearrange the tiles by sliding a tile into the blank square. The goal of the game is to start with the tiles in some random order and then rearrange them to the form below
1 2 3
4 5 6
7 8 9

With 16-tile puzzle, you need to rearrange the tiles to the form below

1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16