Daniel Fischer
Am Freitag 26 Februar 2010 16:50:42 schrieb Ketil Malde:
solutions = [[x1,x2,x3,x4,x5,x6,x7,x8,x9,x10] | x1 <- [0..9]
First digit can't be 0, so make it [1 .. 9]. Since you use the fact that the last digit must be the 0, pull all others from [1 .. 9].
Originally, I pulled from alternating odds (x1 <- [1,3..9] etc) and evens, since this is fairly easy to deduce... I reverted this since the point was to use brute force.
solve :: [Int] -> [[Int]]
Not on a 32-bit system. Word would suffice there, but you don't know that in advance, so it'd be Int64 or Integer
Hm? The Ints are just individual digits here.
I would make the length of the prefix a parameter of solve.
I thought about generating a list with solutions for increasing lenghts, so that e.g. 'solve [] !! 10' would solve this particular problem.
solve prefix = case length prefix of 10 -> return prefix l -> do x <- [0 .. 9] ...
over the if-then-else.
Yes, much nicer. Thanks for the feedback! -k -- If I haven't seen further, it is by standing in the footprints of giants