Express Maze

The Express Maze is an entertaining problem; the point of which is to search for the only correct route on the square field filled with obstacles. Three kinds of obstacles, in cells, indicate some parts of the route. In order to find your way completely, you'll have to think on your feet, because each time you will need to analyze new situations to choose the correct turn.

In the maze the obstacles imposes following rules:
- You may not enter a filled square;
- You may enter the square with a slash twice without crossing the slash;
- You may enter the half painted square only once through a non-painted part of it.

To connect the neighboring squares with a segment, click on their common side. If you need to remove a segment, just click on the edge again.
 This Puzzle's task is to visit all of the vacant cells of the game field by drawing a closed line which does not cross itself.

Let's see how the Express Maze could be solved. To start with, let's mark the parts of the route near square obstacles. Let's also mark the routes coming via the squares which have only two vacant sides.

Now how do we continue the route in the other vacant squares? Quite easy ;) As we can see in the previous picture, there are only two unoccupied sides left in some of the squares. So all we need to do is make a part of the route through these squares. A closer look at the squares will bring us to the right decision. But we should keep in mind that the broken line can not cross itself. And finally we have the solution: