hackerrank random-number-generator (with desmos visualisation)

gistfile1.txt

{-
  random-number-generator: https://www.hackerrank.com/challenges/random-number-generator
  Author: Evgeniy Malov <[email protected]>
  Date: Jan 1, 2025
  join me : https://www.youtube.com/@EvgeniyMalov
            https://ru.linkedin.com/in/deepwalk            
-}
{-# LANGUAGE DuplicateRecordFields, FlexibleInstances, UndecidableInstances #-}

module Main where

import Control.Monad
import Data.Array
import Data.Bits
import Data.List
import Data.List.Split
import Data.Set
import Data.Text
import Debug.Trace
import System.Environment
import System.IO
import System.IO.Unsafe

--
-- Complete the 'solve' function below.
--
-- The function is expected to return a STRING.
-- The function accepts following parameters:
--  1. INTEGER a
--  2. INTEGER b
--  3. INTEGER c
--

solve a b c  
  | a < b = solve' a b c
  | otherwise = solve' b a c

solve' a b c 
    | (c <= a) = f (c*c) (2*total_area) 
    | (a < c) && (c <= b ) = let 
                        tb = c 
                        ta = c - a 
                        h = a 
                    in f ((ta+tb)*h) (2*total_area)  -- trapezoid area
    | (b < c) && (c <= a + b) = let 
                        dy = c - b 
                        dx = (c-a) 
                        dx' = b - dx
                        dy' = a - dy
                        trng_sqr_area = dx'*dy'
                      in f (2*total_area - trng_sqr_area) (2*total_area)
    | otherwise = f 1 1
        where 
            f :: Int -> Int -> String
            f numerator denominator = let g = gcd numerator denominator 
                                in (show $ numerator `div` g) ++ "/" ++ (show $ denominator `div` g)
      
            total_area = a*b
      
      
     
    -- Write your code here

lstrip = Data.Text.unpack . Data.Text.stripStart . Data.Text.pack
rstrip = Data.Text.unpack . Data.Text.stripEnd . Data.Text.pack

main :: IO()
main = do
    stdout <- getEnv "OUTPUT_PATH"
    fptr <- openFile stdout WriteMode

    nTemp <- getLine
    let n = read $ lstrip $ rstrip nTemp :: Int

    forM_ [1..n] $ \n_itr -> do
        firstMultipleInputTemp <- getLine
        let firstMultipleInput = Data.List.words $ rstrip firstMultipleInputTemp

        let a = read (firstMultipleInput !! 0) :: Int

        let b = read (firstMultipleInput !! 1) :: Int

        let c = read (firstMultipleInput !! 2) :: Int

        let result = solve a b c

        hPutStrLn fptr result
        

    hFlush fptr
    hClose fptr

-- some helpfull drawings of probability cases    
-- https://www.desmos.com/calculator/ef0bqflcbr?lang=ru