THE JUMPING FROGS*
On the left are three black frogs and on the right three white frogs. In between is a single space. All you have to do is to make the black and white frogs change places by moving and jumping them over each other.
You can only slide a frog into a space next to it, and you can only jump a frog over one other frog into the space beyond it. How can the frogs change places in as few moves as possible?