Nth Prime

Ringkasan Tantangan

Given a number n, determine what the nth prime is.

Visit the nth-prime exercise on Exercism to read the full instructions and download the exercise files.

Community Solutions

Lihat Solusi Komunitas

The following are the top 3 community solutions by stars:

Solution 1 by @menketechnologies (⭐ 0) — View on Exercism
Solution 2 by @glennj (⭐ 0) — View on Exercism
Solution 3 by @simisc (⭐ 0) — View on Exercism

Source: Exercism sml/nth-prime

💡 Lihat Solusi

fun nthPrime n =
    let fun aux n nextCandidate idNextPrime oddPrimesBeforeIdNextPrime =
            if List.exists (fn x => nextCandidate mod x = 0) oddPrimesBeforeIdNextPrime
            then aux n (nextCandidate + 2) idNextPrime oddPrimesBeforeIdNextPrime
            else
                if idNextPrime = n
                then nextCandidate
                else aux n (nextCandidate + 2) (idNextPrime + 1) (oddPrimesBeforeIdNextPrime @ [nextCandidate] )
    in case (n < 1, n = 1) of
        (true, _) => NONE