Haskell version of HackerRank problem solution "NumberTheory/Restaurant"

Question

Link to the challenge

Given an input of \$T\$ rectangles, each of various dimensions \$l \times b\,ドル what is the minimum number of identical perfect squares that would cover each rectangle with no overlap or excess?

Constraints

\1ドル \le T \le 1000\$
\1ドル \le l\,ドル \$b \le 1000\$

Sample Input

2
2 2
6 9

Sample Output

1
6

---

import System.IO (readLn, getLine)
import Control.Monad (replicateM)
main :: IO ()
main = getNumLoaves >>= getLoafDimensions >>= mapM_ (print . minNumberOfSlices)
getNumLoaves :: IO Int
getNumLoaves = readLn
parseInt :: String -> Int
parseInt = read
tuplefy :: [a] -> (a, a)
tuplefy xs = case xs of [a, b] -> (a, b)
 _ -> error "each line of input must consist of 2 integer values."
getLoafDimensions :: Int -> IO [(Int, Int)]
getLoafDimensions =
 let rawText = flip replicateM getLine
 parseDimensions = map $ tuplefy . map parseInt . words
 in fmap parseDimensions . rawText
squares :: [Int]
squares = map (^2) [1..1000]
squareRoot :: Int-> Int
squareRoot squaredNum = floor . sqrt $ fromIntegral squaredNum
minNumberOfSlices :: (Int, Int) -> Int
minNumberOfSlices (l, b) =
 let area = l * b
 isPerfectSliceDimension num = area `rem` num + b `rem` squareRoot num + l `rem` squareRoot num == 0
 largestSquare = last $ filter isPerfectSliceDimension $ take (min l b) squares
 in if l == b
 then 1
 else area `div` largestSquare

Answer 1

getNumLoaves :: IO Int
getNumLoaves = readLn
parseInt :: String -> Int
parseInt = read 

Theses functions are useless. It's useful when you're writing the code and it's not done yet, but Haskell can actually deduce the types based on what the other functions parameters type, like getLoafDimensions need an int, so readLn must return an int, otherwise it wouldn't compile

Your tuplefy function can be simplified by removing the case of, which is basically the same as this form of pattern matching

tuplefy :: [a] -> (a, a)
tuplefy [a, b] = (a, b)
tuplefy _ = error "each line of input must consist of 2 integer values."

By the way, the error message is wrong, because that function can accept a list of any type

Both readLn and getLine are defined in the prelude, so you don't need to import them, so you don't need to import System.IO