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|
(* Day 3: Part 1 *)
let find_mul text =
let regex_or_err = Re2.create "mul\\(([0-9]{1,3}),([0-9]{1,3})\\)" in
match regex_or_err with
| Ok regex -> (
let matches = Re2.get_matches regex text in
match matches with Ok matches -> matches | Error _ -> [])
| Error _ -> []
let extract_pairs (matches : Re2.Match.t list) : (int * int) list =
List.map
(fun x ->
let left = Re2.Match.get x ~sub:(`Index 1) in
match left with
| None -> (0, 0)
| Some left -> (
let left_num = int_of_string left in
let right = Re2.Match.get x ~sub:(`Index 2) in
match right with
| None -> (0, 0)
| Some right ->
let right_num = int_of_string right in
(left_num, right_num)))
matches
let solve input =
input |> find_mul |> extract_pairs
|> List.fold_left
(fun acc pair ->
let left, right = pair in
acc + (left * right))
0
|
