Swapping Knights Puzzle
Above is a \(3\times3\) board with 4 knights two white knights and two black knights. As in a standard game of chess, the knight can move only two steps in the horizontal or vertical direction and then one step in the other direction for one move. Define an action as moving a knight of any color.
The objective of the game is to interchange the position of both the black and white knights while alternately moving a knight of different color. The final state of the board is:
Using only actions, what is the minimum number of actions required to complete the game?