[Haskell-beginners] Fwd: tower hanoi problem

[Chaddaï Fouché]

On Sat, Feb 21, 2015 at 4:50 PM, Joel Neely <joel.neely at gmail.com> wrote:

> Given a list of fractional numbers, produce a smoothed list, where each
> value is averaged with its immediate neighbors (except the first and last,
> which fail to have both neighbors), as shown below.
>
> [0.0,4.0,2.0,6.0,1.0,2.0]
> [    2.0,4.0,3.0,3.0    ]
>
>
> It seems natural to my eye to express this as, "A list with at least three
> elements contributes a value to the result", as in:
>
> smooth :: Fractional n => [n] -> [n]
> smooth (a:z@(b:c:_)) = (a + b + c) / 3 : smooth z
> smooth _             = []
>
>
>
In Haskell, I would write this with higher-order functions though :

smooth xs = zipWith3 (\a b c -> (a+b+c)/3) xs (drop 1 xs) (drop 2 xs)

-- 
Jedaï
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