Data update

Task/Knuths-algorithm-S/OCaml/knuths-algorithm-s.ml

@@ -0,0 +1,25 @@
+let s_of_n_creator n =
+  let i = ref 0
+  and sample = ref [| |] in
+  fun item ->
+    incr i;
+    if !i <= n then sample := Array.append [| item |] !sample
+    else if Random.int !i < n then !sample.(Random.int n) <- item;
+    !sample
+
+let test n items_set =
+  let s_of_n = s_of_n_creator n in
+  Array.fold_left (fun _ v -> s_of_n v) [| |] items_set
+
+let () =
+  Random.self_init ();
+  let n = 3 in
+  let num_items = 10 in
+  let items_set = Array.init num_items (fun i -> i) in
+  let results = Array.make num_items 0 in
+  for i = 1 to 100_000 do
+    let res = test n items_set in
+    Array.iter (fun j -> results.(j) <- succ results.(j)) res
+  done;
+  Array.iter (Printf.printf " %d") results;
+  print_newline ()