Multi-column Tower of Hanoi problem
introduction
One student saw there a math problem on the Tower of Hanoi on my preliminary round Moni Juan. Probably require a minimum number of movements of the column 20 is 4.
His math is good, to find how should push.
If you want to move to another column n disks, the following steps:
- The plate portion (upper r a) moved to an empty column, a column movement has available 4
- The remaining nr a plate on the other to move empty column, available movement of the column 3 (nr a plate which can not be placed before the column was placed on a plate r)
- The first step of moving a r nr pillars moved over the plate, during the movement of the column there is available 4
In fact, he said, is a multi-column Tower of Hanoi Frame-Stewart algorithm of m = 4 when
Frame-Stewart algorithm
Provided that there are n disks, m pillars
The plate portion (upper r a) moves on an empty column, a column movement has available and m
The remaining nr the other moved to a plate blank columns, column movement available to the root m-1 (which can not be placed nr a plate placed on a plate of the column before r)
The first step of moving a r nr pillars moved over the plate, during the movement of the column there is available and m
Derivations
Set F. M (n) = with m columns, the minimum number of steps of movement required n disks.
then
Fm(n)=min0<r<n{2*Fm(r)+Fm-1(n-r)}
So in the end how much this r is it?
They would have to enumerate slightly ......