/trunk/Fsharp/euler14.fs
 
 
 

 
/trunk/Fsharp/euler14.fs   r5
 
 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 

 

 
 
 
 
 
 
 
1
 
 
 
let seq_length n = n > Seq.unfold(fun x -> match x with
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
2
 
 
 
x when x = 0L -> None
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
3
 
 
 
x when x = 1L -> Some((1L,0L))
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
4
 
 
 
x when x%2L=0L -> Some((x,x/2L))
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
5
 
 
 
_ -> Some((x,3L*x + 1L))
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
6
 
 
 
) > Seq.length
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
7
 
 
 
[for i in 1L..1000000L -> (i, seq_length i)]
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
8
 
 
 
> List.fold1_left(fun (ai,al) (i,l) -> if l > al then (i,l) else (ai,al) )
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
9
 
 
 
> (fun (x,y) -> x ) > print_any