You have a 4×5 chess board as follows:

You can move the four bishops in any order (not necessarily alternating black and white), provided that no move puts a piece in danger of being captured by a bishop of the opposite color.

What is the fewest number of moves needed for the black and white bishops to exchange places?

a3b2, e3d2, d2b4, b2d4, d4e3, a1b2, b2c1, e1c3, c3a1, b4c3, c1a3, e3c1, c3d4, a3b4, b4e1, c1d2, d4b2, b2a3, d2e3

Sorry for the crude layout. I double-checked it, and I think that this is the way to switch the places of black and white figures. I'm not sure if it's the only way (the symetric doesn't count ;) ), and if it's the optimal solution to the problem. Anyone?

Posted by slsl on 2004-03-01 14:18:40