enkoi.hs

-- 1
main = interact $ show . sum . map read . tail . lines

-- 2
f [a, b, c] = if a <= b then 0 else (a-b)*c

main = interact $ show . sum . map (f . map read . words) . tail . lines

-- 3
import Control.DeepSeq

f (t : _ : xs) = psums `deepseq` maximum diffs
    where psums = scanl (+) 0 xs
          diffs = zipWith (-) (drop t psums) psums

main = interact $ show . f . map read . words