Cheryl's birthday: Difference between revisions

=={{header|F_Sharp|F#}}==

<lang fsharp>

//Find Cheryl's Birthday. Nigel Galloway: October 23rd., 2018

type Month = |May |June |July |August

let fN n= n |> List.filter(fun (_,n)->(List.length n) < 2) |> List.unzip

let dates = [(May,15);(May,16);(May,19);(June,17);(June,18);(July,14);(July,16);(August,14);(August,15);(August,17)]

let _,n = dates |> List.groupBy(fun (_,n)-> n) |> fN

let i = n |> List.concat |> List.map(fun (n,_)->n) |> Set.ofList

let _,g = dates |> List.filter(fun (n,_)->not (Set.contains n i)) |> List.groupBy(fun (_,n)-> n)|> fN

let _,e = List.concat g |> List.groupBy(fun (n,_)->n) |> fN

printfn "%A" e

</lang>

{{out}}

<pre>

[[(July, 16)]]

</pre>