tasks a-s

2013-04-10 23:57:08 -07:00 · 2013-04-10 23:57:08 -07:00 · b83f433714
commit b83f433714
parent 47bf37c096
12433 changed files with 156208 additions and 123 deletions
--- a/Task/Roman-numerals-Decode/Haskell/roman-numerals-decode.hs
+++ b/Task/Roman-numerals-Decode/Haskell/roman-numerals-decode.hs
@ -0,0 +1,9 @@
+import Data.List (isPrefixOf)
+
+mapping = [("M",1000),("CM",900),("D",500),("CD",400),("C",100),("XC",90),
+           ("L",50),("XL",40),("X",10),("IX",9),("V",5),("IV",4),("I",1)]
+
+toArabic :: String -> Int
+toArabic "" = 0
+toArabic str = num + toArabic xs
+    where (num, xs):_ = [ (num, drop (length n) str) | (n,num) <- mapping, isPrefixOf n str ]