Data commit

Task/Spiral-matrix/OCaml/spiral-matrix-1.ocaml

@@ -0,0 +1,39 @@
+let next_dir = function
+  |  1,  0 ->  0, -1
+  |  0,  1 ->  1,  0
+  | -1,  0 ->  0,  1
+  |  0, -1 -> -1,  0
+  | _ -> assert false
+
+let next_pos ~pos:(x,y) ~dir:(nx,ny) = (x+nx, y+ny)
+
+let next_cell ar ~pos:(x,y) ~dir:(nx,ny) =
+  try ar.(x+nx).(y+ny)
+  with _ -> -2
+
+let for_loop n init fn =
+  let rec aux i v =
+    if i < n then aux (i+1) (fn i v)
+  in
+  aux 0 init
+
+let spiral ~n =
+  let ar = Array.make_matrix n n (-1) in
+  let pos = 0, 0 in
+  let dir = 0, 1 in
+  let set (x, y) i = ar.(x).(y) <- i in
+  let step (pos, dir) =
+    match next_cell ar pos dir with
+    | -1 -> (next_pos pos dir, dir)
+    | _ -> let dir = next_dir dir in (next_pos pos dir, dir)
+  in
+  for_loop (n*n) (pos, dir)
+           (fun i (pos, dir) -> set pos i; step (pos, dir));
+  (ar)
+
+let print =
+  Array.iter (fun line ->
+    Array.iter (Printf.printf " %2d") line;
+    print_newline())
+
+let () = print(spiral 5)

Task/Spiral-matrix/OCaml/spiral-matrix-2.ocaml

@@ -0,0 +1,17 @@
+let spiral n =
+   let ar = Array.make_matrix n n (-1) in
+   let out i = i < 0 || i >= n in
+   let too_far (x,y) = out x || out y || ar.(x).(y) >= 0 in
+   let step x y (dx,dy) = (x+dx,y+dy) in
+   let turn (i,j) = (j,-i) in
+   let rec iter (x,y) d i =
+      ar.(x).(y) <- i;
+      if i < n*n-1 then
+         let d' = if too_far (step x y d) then turn d else d in
+         iter (step x y d') d' (i+1) in
+   (iter (0,0) (0,1) 0; ar)
+
+let show =
+   Array.iter (fun v -> Array.iter (Printf.printf " %2d") v; print_newline())
+
+let _ = show (spiral 5)