1 files changed, 34 insertions(+), 0 deletions(-)

A day_3.ml

@@ 0,0 1,34 @@
+let bool_to_int b = match b with | true -> 1 | false -> 0
+
+let rec read_input chan =
+	match (try Some (input_line chan) with End_of_file -> None) with
+	| Some line -> line :: read_input chan
+	| None -> []
+
+let get_path lst offset (x, y) =
+	let new_lst = List.filteri (fun i v -> (i mod y) = 0) lst in
+	let rec aux lst offset dx =
+		match lst with
+		| [] -> 0
+		| str::tail ->
+				let curr = (bool_to_int (str.[offset mod String.length str] = '#')) in
+				(+) curr (aux tail (offset + dx) dx)
+	in
+	aux new_lst offset x
+
+let _ =
+	let in_chan = open_in "day_3.in" in
+	let lst = read_input in_chan in
+	close_in in_chan;
+	let slopes = [ (1, 1); (3, 1); (5, 1); (7, 1); (1, 2) ] in
+
+	let val1 = get_path lst 0 (List.nth slopes 1) in
+	let out_chan1 = open_out "day_3_1.out" in
+	Printf.fprintf out_chan1 "%d\n" val1;
+	close_out out_chan1;
+
+	let val2 = List.fold_left ( * ) 1 (List.map (get_path lst 0) slopes) in
+	let out_chan2 = open_out "day_3_2.out" in
+	Printf.fprintf out_chan2 "%d\n" val2;
+	close_out out_chan2;
+	()