adventofcode2021_ex1.hs

sweeps :: [Integer]
sweeps = [199,
 200,
 208,
 210,
 200,
 207,
 240,
 269,
 260,
 263]

countSweepsWindows :: (Ord b, Num a) => [b] -> a
countSweepsWindows xs = foldl (\acc x -> if ((snd x) > (fst x)) then acc + 1 else acc) 0 $ zip xs (drop 1 xs)

slidingWindowSweeps :: Int -> Int -> [a] -> [[a]]
slidingWindowSweeps n d [] = []
slidingWindowSweeps n d xs = [take n xs] ++ slidingWindowSweeps n d (drop d xs)

part1 :: (Ord b, Num a) => [b] -> a
part1 xs = countSweepsWindows xs

part2 :: (Ord b, Num a, Num b) => [b] -> a
part2 xs = countSweepsWindows $ map (sum) $ filter (\x -> length x == 3) (slidingWindowSweeps 3 1 xs)

well done, need to read up on my haskell. Here are my answers:
perl -lne '$sum += 1 if $prev and ($_ - $prev) > 0; $prev = $_; END { print $sum }' input.txt
perl -lne '$sum += 1 if $n_1 and $n_2 and $n_3 and ($_ + $n_1 + $n_2) - ($n_1 + $n_2 + $n_3) > 0; $n_3 = $n_2; $n_2 = $n_1; $n_1 = $_; END { print $sum }' input.txt