list gcd

gistfile1.txt

main = do
  getLine
  pss <- read . lines . getContents
  print $ foldr1 pss


-- list of numbers in the form of prime-power pairs
-- e.g. 35 would be [5 1 7 1]
gcd' _ [] = []
gcd' [] _ = []
gcd' (x0:x1:xs) (y0:y1:ys) = case compare x0 y0 of
  EQ -> (x0:[ min x1 y1]) : gcd' xs ys
  LT -> gcd' xs (y0:y1:ys)
  GT -> gcd' (x0:x1:xs) ys