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Haskell - Usage of higher order functions (2) P31745

Statement

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Implement the following functions using higher-order functions (and other predefined functions) of Haskell without using recursion.

Implement a function flatten :: [[Int]] -> [Int] that flattens a list of lists of integers in a list of integers.
Implement a function myLength :: String -> Int that returns the length of a string.
Implement a function myReverse :: [Int] -> [Int] that reverses a list of integers.
Implement a function countIn :: [[Int]] -> Int -> [Int] that, given a list of sublists ℓ and an element x, returns the list that tells who many times x appears in each sublist of ℓ.
Implement a function firstWord :: String -> String that, given a string with blanks and alphabetic characters, returns its first word.

Scoring

Each function scores 20 points.

Public test cases

Input

flatten [[1,2,3],[4,5],[6],[],[3,3]]
myLength "Albert"
myReverse [1..10]
countIn [[3,2,3],[3],[], [2,2]] 3
firstWord "  Volem pa amb oli  "

Output

[1,2,3,4,5,6,3,3]
6
[10,9,8,7,6,5,4,3,2,1]
[2,1,0,0]
"Volem"

Information