Hello I am trying to use the alienTile problem described at www.alientiles.com using the A* algorithm but I cannot find any good heuristic function so far.
In alien tiles you have a board with NxN tiles, all colored red. By clicking on a tile, all tiles in the same row and column advance by a color, the color order being red->green->blue->purple, resetting to red after purple. The goal is to change all tiles to the specified colors. The simplest goal state is all the tiles going from red to green, blue or purple. The board doesn't have to be 7x7 as the site suggests.
Is there any good point to start because I am completely frustrated about how I am supposed to handle the problem