diff --git a/Problem17.hs b/Problem17.hs new file mode 100644 index 0000000..601fdb3 --- /dev/null +++ b/Problem17.hs @@ -0,0 +1,33 @@ +-- If all the numbers from 1 to 1000 (one thousand) inclusive were written +-- out in words, how many letters would be used? +-- +-- NOTE: Do not count spaces or hyphens. For example, 342 (three hundred and +-- forty-two) contains 23 letters and 115 (one hundred and fifteen) contains +-- 20 letters. The use of "and" when writing out numbers is in compliance +-- with British usage. + +import Data.Char +import Data.List + +inWords :: Integer -> String +inWords n + | n < 0 = "negative " ++ inWords (negate n) + | n <= 19 = [ "zero", "one", "two", "three", "four", "five", "six" + , "seven", "eight", "nine", "ten", "eleven", "twelve" + , "thirteen", "fourteen", "fifteen", "sixteen" + , "seventeen", "eighteen", "nineteen" + ] !! fromInteger n + | n <= 99 = case n `divMod` 10 of + (m, q) -> let tens = [ "twenty", "thirty", "forty", "fifty" + , "sixty", "seventy", "eighty", "ninety" ] + in (tens !! fromInteger (m - 2)) ++ + (if q == 0 then "" else ("-" ++ inWords q)) + | n <= 999 = case n `divMod` 100 of + (m, 0) -> inWords m ++ " hundred" + (m, r) -> inWords m ++ " hundred and " ++ inWords r + | n <= 9999 = case n `divMod` 1000 of + (m, 0) -> inWords m ++ " thousand" + (m, r) | r <= 99 -> inWords m ++ " thousand and " ++ inWords r + | otherwise -> inWords m ++ " thousand " ++ inWords r + +main = print $ length $ filter isAlpha $ concatMap inWords [1..1000] diff --git a/Problem18.hs b/Problem18.hs new file mode 100644 index 0000000..55923cc --- /dev/null +++ b/Problem18.hs @@ -0,0 +1,24 @@ +-- Find the maximum total from top to bottom of the triangle below: +import Data.List + +triangle = + [ [ 75 ] + , [ 95,64 ] + , [ 17,47,82 ] + , [ 18,35,87,10 ] + , [ 20,04,82,47,65 ] + , [ 19,01,23,75,03,34 ] + , [ 88,02,77,73,07,63,67 ] + , [ 99,65,04,28,06,16,70,92 ] + , [ 41,41,26,56,83,40,80,70,33 ] + , [ 41,48,72,33,47,32,37,16,94,29 ] + , [ 53,71,44,65,25,43,91,52,97,51,14 ] + , [ 70,11,33,28,77,73,17,78,39,68,17,57 ] + , [ 91,71,52,38,17,14,91,43,58,50,27,29,48 ] + , [ 63,66,04,68,89,53,67,30,73,16,69,87,40,31 ] + , [ 04,62,98,27,23,09,70,98,73,93,38,53,60,04,23 ] + ] + +maxLR xs = zipWith max xs (tail xs) +routes = head . foldr1 (\xs ys -> zipWith (+) xs $ maxLR ys) +main = print $ routes triangle