10 lines
154 B
OCaml
10 lines
154 B
OCaml
let fib n =
|
|
let rec real = function
|
|
0 -> 1
|
|
| 1 -> 1
|
|
| n -> real (n-1) + real (n-2)
|
|
in
|
|
if n < 0 then
|
|
None
|
|
else
|
|
Some (real n)
|