Lunar Lockout has the following formal description. Read the description carefully.
- The puzzle is played on a square board that is a grid board with N squares in the x-dimension and N squares in the y-dimension. The dimension N is always odd.
- Each state in the game contains the x and y coordinates for each robot as well as the x and y coordinates for each rover (or xanadu).
- From each state, each robot and each rover can move North, South, East, or West, but only if there is a second robot or rover that lies in that direction. When a robot or rover moves, it must move all the way to the second piece until the pieces collide. For example, if a robot located at position (4;0) moves South toward a rover located at (4;3), the robot will end at the location (4;2). No two pieces (robots or rovers) can move simultaneously or diagonally and pieces cannot pass through walls or one another.
- The escape hatch is always located in the center of the board (i.e. at the grid location ((N-1)/2, (N-1)/2).
- Once a rover arrives at the escape hatch, it exits the board through the escape hatch. It then disappears from subsequent play.
- Each movement is of equal cost.
- The goal is achieved when all rovers have exited the board via the escape hatch.
f = g(node)+w*h(node)