Data commit

Task/Averages-Median/F-Sharp/averages-median.fs

@@ -0,0 +1,44 @@
+let rec splitToFives list =
+    match list with
+        | a::b::c::d::e::tail ->
+            ([a;b;c;d;e])::(splitToFives tail)
+        | [] -> []
+        | _ ->
+                let left = 5 - List.length (list)
+                let last = List.append list (List.init left (fun _ -> System.Double.PositiveInfinity) )
+                in [last]
+
+let medianFromFives =
+    List.map ( fun (i:float list) ->
+        List.nth (List.sort i) 2 )
+
+let start l =
+    let rec magicFives list k =
+        if List.length(list) <= 10 then
+            List.nth (List.sort list) (k-1)
+        else
+            let s = splitToFives list
+            let M = medianFromFives s
+            let m = magicFives M (int(System.Math.Ceiling((float(List.length M))/2.)))
+            let (ll,lg) = List.partition ( fun i -> i < m ) list
+            let (le,lg) = List.partition ( fun i -> i = m ) lg
+            in
+               if (List.length ll >= k) then
+                    magicFives ll k
+               else if (List.length ll + List.length le >= k ) then m
+               else
+                    magicFives lg (k-(List.length ll)-(List.length le))
+    in
+        let len = List.length l in
+        if (len % 2 = 1) then
+            magicFives l ((len+1)/2)
+        else
+            let a = magicFives l (len/2)
+            let b = magicFives l ((len/2)+1)
+            in (a+b)/2.
+
+
+let z = [1.;5.;2.;8.;7.;2.]
+start z
+let z' = [1.;5.;2.;8.;7.]
+start z'