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Diffstat (limited to 'aoc2023/src/day4/solve.gleam')
-rw-r--r-- | aoc2023/src/day4/solve.gleam | 98 |
1 files changed, 0 insertions, 98 deletions
diff --git a/aoc2023/src/day4/solve.gleam b/aoc2023/src/day4/solve.gleam deleted file mode 100644 index 34d6098..0000000 --- a/aoc2023/src/day4/solve.gleam +++ /dev/null @@ -1,98 +0,0 @@ -import adglent.{First, Second} -import gleam/bool -import gleam/dict.{type Dict} -import gleam/int -import gleam/io -import gleam/list -import gleam/option.{None, Some} -import gleam/result -import gleam/set.{type Set} -import gleam/string - -type Card { - Card(number: Int, winners: Int) -} - -fn numbers_to_set(str: String) -> Set(Int) { - str - |> string.split(" ") - |> list.map(int.parse) - |> result.values() - |> set.from_list() -} - -fn parse_card(card: String) -> Card { - let assert Ok(#("Card" <> n_str, rest)) = string.split_once(card, ": ") - let assert Ok(#(winning_str, has_str)) = string.split_once(rest, " | ") - let assert Ok(n) = int.parse(string.trim(n_str)) - - let winning = numbers_to_set(winning_str) - let has = numbers_to_set(has_str) - let winners = set.size(set.intersection(winning, has)) - - Card(number: n, winners: winners) -} - -fn win_points(n: Int) { - bool.guard(n < 2, n, fn() { 2 * win_points(n - 1) }) -} - -pub fn part1(input: String) { - use acc, c <- list.fold(string.split(input, "\n"), 0) - c - |> parse_card - |> fn(c: Card) { win_points(c.winners) } - |> int.add(acc) -} - -fn win_more_cards(cards: List(String), count: Dict(Int, Int)) { - case cards { - [] -> - count - |> dict.values - |> int.sum - [raw_card, ..rest] -> { - let card = parse_card(raw_card) - case card.winners { - 0 -> win_more_cards(rest, count) - n -> win_more_cards(rest, update_counts(n, card, count)) - } - } - } -} - -fn update_counts(n: Int, card: Card, count: Dict(Int, Int)) -> Dict(Int, Int) { - let assert Ok(bonus) = dict.get(count, card.number) - use acc, n <- list.fold(list.range(card.number + 1, card.number + n), count) - use c <- dict.update(acc, n) - case c { - Some(i) -> i + bonus - None -> panic as "won a card that doesn't exist in the card pile" - } -} - -pub fn part2(input: String) { - let cards = string.split(input, "\n") - - let count = - list.range(1, list.length(cards)) - |> list.map(fn(n) { #(n, 1) }) - |> dict.from_list() - - win_more_cards(cards, count) -} - -pub fn main() { - let assert Ok(part) = adglent.get_part() - let assert Ok(input) = adglent.get_input("4") - case part { - First -> - part1(input) - |> adglent.inspect - |> io.println - Second -> - part2(input) - |> adglent.inspect - |> io.println - } -} |