You can navigate the grid below from the top-left yellow circle to the bottom-right yellow square by making only orthogonal (not diagonal) moves, going from one position to the next only if the shape and/or the color of the shape in the entered cell is the same as that of the cell you are leaving.

• What path has the minimum number of moves without going through the same cell twice?
• What path has the maximum number of moves without going through the same cell twice?

direction R:right L:left U:up D:down

the best minimum I can find is 22 with the following moves
DDRDLDRDRURUURURDDDLDR

The best maximum I can find is 26 with the following moves
RRRDLDLDLDRDRURUURURDDDLDR

and I don't see any other shorter or longer paths

Posted by Daniel on 2009-10-07 12:02:35