Euler #5

Euler #5 solution

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let multiplesOf x = Seq.initInfinite (fun i -> (i+1) * x)

let leastCommonDenominator x y =
    Seq.find (fun i -> i%x = 0) (multiplesOf y)

let problem5 n =
    let testDenominator lcd =
        List.forall (fun i -> lcd % i = 0) [n-2 .. -1 .. 1]

    let rec problem5Helper (x, lcd) =
        match testDenominator lcd with
            | true -> lcd
            | false ->
                let lcd2 = leastCommonDenominator (x-1) (x-2)
                problem5Helper (x-1, (leastCommonDenominator lcd lcd2))
    
    problem5Helper (n, (leastCommonDenominator n n-1))

val multiplesOf : x:int -> seq<int>

Full name: Script.multiplesOf

val x : int

module Seq

from Microsoft.FSharp.Collections

val initInfinite : initializer:(int -> 'T) -> seq<'T>

Full name: Microsoft.FSharp.Collections.Seq.initInfinite

val i : int

val leastCommonDenominator : x:int -> y:int -> int

Full name: Script.leastCommonDenominator

val y : int

val find : predicate:('T -> bool) -> source:seq<'T> -> 'T

Full name: Microsoft.FSharp.Collections.Seq.find

val problem5 : n:int -> int

Full name: Script.problem5

val n : int

val testDenominator : (int -> bool)

val lcd : int

Multiple items
module List

from Microsoft.FSharp.Collections

--------------------
type List<'T> =
  | ( [] )
  | ( :: ) of Head: 'T * Tail: 'T list
  interface IEnumerable
  interface IEnumerable<'T>
  member Head : 'T
  member IsEmpty : bool
  member Item : index:int -> 'T with get
  member Length : int
  member Tail : 'T list
  static member Cons : head:'T * tail:'T list -> 'T list
  static member Empty : 'T list

Full name: Microsoft.FSharp.Collections.List<_>

val forall : predicate:('T -> bool) -> list:'T list -> bool

Full name: Microsoft.FSharp.Collections.List.forall

val problem5Helper : (int * int -> int)

val lcd2 : int

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More information

Link:	http://fssnip.net/7u
Posted:	12 years ago
Author:	Michael Falanga
Tags:	euler problem , algorithm , recursion , lists , learning f# , puzzles , seq