motylwg

type Peg =  
    | A
    | B
    | C
 
type Move = 
    | Move of int * Peg * Peg
    static member toString m = 
        match m with
        | Move(n, p1, p2) when n <> 1 -> sprintf "move %i %A %A" n p1 p2

motylwg

let rec sieve (xs : int seq) = 
    seq {
      let p = xs |> Seq.take 1 |> Seq.exactlyOne 
      yield p
      yield! xs |> Seq.skip 1 |> Seq.filter (fun x -> x % p <> 0) |> sieve
    }
  
let ints = Seq.initInfinite (fun x -> x + 2)
let primes = sieve ints

motylwg

type position = int * int
type board = position list

let queens n = 
    let isNotAttack (p1 : position) (p2 : position) = 
        fst p1 <> fst p2 && snd p1 <> snd p2 && abs (fst p1 - fst p2) <> abs (snd p1 - snd p2)

    let isSafe (b : board) = 
        match b with 
        | [] -> true

motylwg

def sieve(s: Stream[Int]): Stream[Int] =
  s.head #:: sieve(s.tail filter(_ % s.head != 0))
                                                  
val primes = sieve(Stream.from(2))                     
  
primes.take(100).toList