diff options
| -rw-r--r-- | day19.fsx | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/day19.fsx b/day19.fsx new file mode 100644 index 0000000..f30c140 --- /dev/null +++ b/day19.fsx @@ -0,0 +1,15 @@ +open System + +let rec josephus = + function + | 1 -> 1 + | x -> (if x % 2 <> 0 then 1 else -1) + 2 * josephus (x / 2) + +let josephus' (target: int): int = + let pow = Math.Pow(3, Math.Floor(Math.Log(target, 3))) |> int + if pow = target then pow + else if pow >= target / 2 then target - pow + else pow + (2 * (target - 2 * pow)) + +josephus 3017957 |> printfn "%d" +josephus' 3017957 |> printfn "%d" \ No newline at end of file |