Alternating glasses a. There are 2n glasses standing next to each other in a row, th...

Alternating glasses

a. There are 2n glasses standing next to each other in a row, the first n of them filled with a soda drink and the remaining n glasses empty. Make the glasses alternate in a filled-empty-filled-empty pattern in the minimum number of glass moves. [Gar78]

b. Solve the same problem if 2n glasses—n with a drink and n empty—are initially in a random order.