Hi Slavomir,
Slavomir Kaslev wrote:
inter x [] = [[x]]
inter x yys@(y:ys) = [x:yys] ++ map (y:) (inter x ys)
perm [] = [[]]
perm (x:xs) = concatMap (inter x) (perm xs)
I was surprised to find that not only my version is much simpler from the one
in Data.List but it also performs better.
Thank you for the comprehensive reply Yitzchak.
On Wed, Aug 5, 2009 at 2:22 PM, Yitzchak Galeg...@sefer.org wrote:
Hi Slavomir,
Slavomir Kaslev wrote:
inter x [] = [[x]]
inter x yys@(y:ys) = [x:yys] ++ map (y:) (inter x ys)
perm [] = [[]]
perm (x:xs) = concatMap (inter x) (perm xs)
I
Your function is not equivalent:
perm _|_ = _|_
permutations _|_ = _|_ : _|_
On 8/4/09, Slavomir Kaslev slavomir.kas...@gmail.com wrote:
A friend mine, new to functional programming, was entertaining himself by
writing different combinatorial algorithms in Haskell. He asked me for some
help
On Tue, Aug 4, 2009 at 8:53 PM, Krasimir Angelovkr.ange...@gmail.com wrote:
Your function is not equivalent:
perm _|_ = _|_
permutations _|_ = _|_ : _|_
Nice catch. One can use the same trick as in permutations:
perm2 [] = [[]]
perm2 xxs@(x:xs) = xxs : tail (concatMap (inter x) (perm2
Am Dienstag 04 August 2009 19:48:25 schrieb Slavomir Kaslev:
A friend mine, new to functional programming, was entertaining himself by
writing different combinatorial algorithms in Haskell. He asked me for some
help so I sent him my quick and dirty solutions for generating variations
and
On Tue, Aug 4, 2009 at 9:23 PM, Daniel Fischerdaniel.is.fisc...@web.de wrote:
Am Dienstag 04 August 2009 19:48:25 schrieb Slavomir Kaslev:
A friend mine, new to functional programming, was entertaining himself by
writing different combinatorial algorithms in Haskell. He asked me for some
help
Am Dienstag 04 August 2009 20:30:58 schrieb Slavomir Kaslev:
On Tue, Aug 4, 2009 at 9:23 PM, Daniel Fischerdaniel.is.fisc...@web.de
wrote:
Which version of ghc are you testing on? I guess, it's more recent than
mine.
6.10.3. But I think if you compiled it with 6.8.*, the library code would
Your function is not equivalent:
perm _|_ = _|_
permutations _|_ = _|_ : _|_
I have a vague memory that the library version diagonalises properly,
so that if you give it a lazy infinite input, it still generates
sensible output lazily. If so, this important property should be
noted in
