Problem 31

Determine whether a given integer number is prime.

Example:

isPrime 113 == True

Unit Test

import Html

isPrime : Int -> Bool
isPrime n = 
    -- your implementation goes here
    False

main : Html.Html a
main =
    Html.text <|
        case test of
            0 ->
                "Your implementation passed all tests."

            1 ->
                "Your implementation failed one test."

            x ->
                "Your implementation failed " ++ (toString x) ++ " tests."


test : Int
test =
    List.length <|
        List.filter (\( result, expect ) -> result /= expect)
            [ ( isPrime 36, False )
            , ( isPrime 10, False )
            , ( isPrime -1, False )
            , ( isPrime 1, False )
            , ( isPrime 0, False )
            , ( isPrime 120, False )
            , ( isPrime 2, True )
            , ( isPrime 23, True )
            , ( isPrime 6000, False )
            , ( isPrime 7919, True )
            , ( isPrime 7911, False )
            , ( isPrime 63247, True )
            , ( isPrime 63249, False )
            ]

Hints

1. Try the Sieve of Eratosthenes. List.filter will come in handy.

Solutions

Solutions