diff options
Diffstat (limited to 'aoc2023-gleam/src/day14/solve.gleam')
-rw-r--r-- | aoc2023-gleam/src/day14/solve.gleam | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/aoc2023-gleam/src/day14/solve.gleam b/aoc2023-gleam/src/day14/solve.gleam new file mode 100644 index 0000000..ecc5361 --- /dev/null +++ b/aoc2023-gleam/src/day14/solve.gleam @@ -0,0 +1,94 @@ +import adglent.{First, Second} +import gleam/dict +import gleam/int +import gleam/io +import gleam/list +import gleam/order +import gleam/string + +fn parse(input) { + input + |> string.split("\n") + |> list.map(string.to_graphemes) + |> list.transpose() +} + +fn roll_boulders(strs: List(String)) { + { + use chunks <- list.map(list.chunk(strs, fn(c) { c == "O" || c == "." })) + list.sort(chunks, order.reverse(string.compare)) + } + |> list.flatten +} + +fn score(matrix) { + use acc, col <- list.fold(matrix, 0) + acc + + { + use col_acc, char, n <- list.index_fold(list.reverse(col), 0) + case char { + "O" -> col_acc + n + 1 + _ -> col_acc + } + } +} + +pub fn part1(input: String) { + input + |> parse + |> list.map(roll_boulders) + |> score() + |> string.inspect +} + +fn rotate(matrix) { + matrix + |> list.map(list.reverse) + |> list.transpose +} + +fn spin(matrix) { + use acc, _ <- list.fold(list.range(1, 4), matrix) + acc + |> list.map(roll_boulders) + |> rotate +} + +fn spin_cycle(matrix) { + let cache = dict.new() + check_if_seen(matrix, cache, 1_000_000_000) +} + +fn check_if_seen(matrix, cache, count) { + case dict.get(cache, matrix) { + Error(Nil) -> + check_if_seen(spin(matrix), dict.insert(cache, matrix, count), count - 1) + Ok(n) -> { + let assert Ok(extra) = int.modulo(count, n - count) + list.fold(list.range(1, extra), matrix, fn(acc, _) { spin(acc) }) + |> score + } + } +} + +pub fn part2(input: String) { + input + |> parse + |> spin_cycle + |> string.inspect +} + +pub fn main() { + let assert Ok(part) = adglent.get_part() + let assert Ok(input) = adglent.get_input("14") + case part { + First -> + part1(input) + |> adglent.inspect + |> io.println + Second -> + part2(input) + |> adglent.inspect + |> io.println + } +} |