Advent of Code 2021, Day 1

y2021d1.ml

let input = Util.read_file "../input/y2021d1" |> List.map int_of_string

(* let%test _ = input = ["1"] *)

(* let%expect_test _ =
   input |> List.iter (fun s -> print_endline s);
   [%expect ""] *)

let prevs xs = xs |> List.rev |> List.tl |> List.rev

let nexts = List.tl

let increases input =
  List.combine (prevs input) (nexts input)
  |> List.map (fun (h, t) -> t - h)
  |> List.filter (fun i -> i > 0)
  |> List.length

let firsts = input |> List.rev |> List.tl |> List.tl |> List.rev
let seconds = input |> List.tl |> List.rev |> List.tl |> List.rev
let thirds = input |> List.tl |> List.tl

let windows =
  List.combine firsts seconds
  |> List.map (fun (a, b) -> a + b)
  |> List.combine thirds
  |> List.map (fun (a, b) -> a + b)

let part1 = increases input
(* let _ = part1 |> string_of_int |> print_endline *)

let part2 = increases windows
(* let _ = part2 |> string_of_int |> print_endline *)