Data commit

Task/Population-count/OCaml/population-count.ocaml

@@ -0,0 +1,25 @@
+let popcount n =
+  let rec aux acc = function
+    | 0 -> acc
+    | x -> aux (succ acc) (x land pred x)
+  in
+  aux 0 n
+
+let is_parity p x =
+  p = 1 land popcount x
+
+(* test code *)
+
+let powers3_seq () =
+  Seq.unfold (fun x -> Some (popcount x, x * 3)) 1
+
+let parity_seq p =
+  Seq.(filter (is_parity p) (ints 0))
+
+let print_seq_30 s =
+  Seq.(s |> take 30 |> map string_of_int)
+  |> List.of_seq |> String.concat " " |> print_endline
+
+let () = print_seq_30 (powers3_seq ())
+let () = print_seq_30 (parity_seq 0)
+let () = print_seq_30 (parity_seq 1)