I have defined the first line it seems right to me but second line not sure. I have True or False and whatever value i give it produces that value.
allEqual :: [Int] -> Bool allEqual (x1:x2:xs) = (x1 == x2) && allEqual xs allEqual _ = ??? Steve Schafer wrote: > > On Thu, 19 Jul 2007 10:55:19 -0700 (PDT), you wrote: > >>The question suggests to use some functions defined in the section, and one >>of them is iSort. > > Aha. Well, that one certainly lends itself better to this particular > proplen than either map or filter. > >>minimumValue :: [Int] -> Int >>minimumValue ns = head (iSort ns) > > If I were going to use a sort, then yes, that's the way I would do it. > Of course, sorting isn't the best way to solve the problem, as sorting > will always be at least O(n * log n), whereas a more straightforward > algorithm would be O(n). > >>The other question is to test whether the values of allEqual on inputs 0 to >>n are all equal. Again, I defined the method but not sure if its concise? >> >>allEqual :: [Int] -> Bool >>allEqual xs = length xs == length (filter isEqual xs) >> where >> isEqual n = (head xs) == n > > Simple recursion is probably the most conceptually straightforward > approach here. One little difficulty with this problem (and with > minimumValue, too) is that the problem isn't completely specified, > because we don't know what answer we're supposed to give when the list > is empty. Let's assume that allEqual is supposed to return True on an > empty list. In that case, we can write it like this: > > allEqual :: [Int] -> Bool > allEqual (x1:x2:xs) = ??? > allEqual _ = ??? > > where the two ???s are left as an exercise for the reader. > > -Steve > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > -- View this message in context: http://www.nabble.com/Producing-MinimumValue-tf4106379.html#a11696192 Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe