On Fri, Feb 13, 2015 at 1:39 PM, Roelof Wobben <r.wobben@home.nl> wrote:

Hello,

After a short break I try to make the next assignment of the CIS 194 course.
I do self-study.

Lets say we have 1 disk with 2 pegs then we have this :

type Peg = String.
type Move = (Peg, Peg)
Hanoi :: Integer -> Peg -> Peg -> [Move]

So I can do this Hanoi 2 a b

How can I proceed further.

I do not see how I can tell that the disk can move from a to b
And I do not see what the base case will be . I think when a is empty and b has a value.

It's a recursion problem. So you tackle it like any other recursion problem:

· Divide your input into two cases: the terminal one that ends the recursion and the one you recurse on.

· Decide how to handle the terminal case. In this case, you'll return a list consisting of one move.

· Decide how to divide the non-terminal case into at least two sub-problems that are all closer to the terminal case by some measurement.

· Write the code that makes the non-terminal calls and combines their values to create your return value.

In cases where your function returns a list, the combination is almost always appending one case to the other.