The programs:
-- common part
module Main where
reverse1 [] ys = ys
reverse1 (x:xs) ys = reverse1 xs (x:ys)
reverse2 ys [] = ys
reverse2 ys (x:xs) = reverse2 (x:ys) xs
-- program t1
main = print (length $! reverse1 [1..200] [])
Actually, presumably you meant:
> reverse2 ys (x:xs) = reverse2 (x:ys) xs
(stupid cut & paste late at night).
with this fix (and now we actually are reversing the list with reverse2),
we get the following timings for reverse2:
11:49pm enescu:~/ time a.out
200
4.64u 0.31s 0:05.18 95.5%
11:49
Well, I assume you meant:
reverse1 [] ys = ys
reverse1 (x:xs) ys = reverse1 xs (x:ys)
reverse2 ys [] = ys
reverse2 ys (x:xs) = reverse1 (x:ys) xs
If so, and you make two programs:
main = print (length $! reverse1 [1..200] [])
and
main = print (length $! reverse2 [] [1..200])
compile
Hello.
Please, tell me which set of definitions below should I expected
to be more efficient: the reverse1 or the reverse2 functions.
reverse1 [] ys = ys
reverse1 (x:xs) ys = reverse2 (x:ys) xs
reverse2 ys [] = ys
reverse2 ys (x:xs) = reverse2 (x:ys) xs
The difference rely on the posit
