Haskell — Usage of higer-order functions (2)

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

1.  Implement a function flatten :: [[Int]] -> [Int] that flattens a
    list of lists of integers in a list of integers.

2.  Implement a function myLength :: String -> Int that returns the
    length of a string.

3.  Implement a function myReverse :: [Int] -> [Int] that reverses a
    list of integers.

4.  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.

5.  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.

Problem information

Author: Unknown
Translator: Jordi Petit

Generation: 2026-02-03T17:11:10.229Z

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