Advent of Code in Gleam

aoc.gleam

import gleam/int
import gleam/list
import gleam/erlang/file
import gleam/string

// 01.txt is a list of the caloric values of the snacks that elves are carrying.
// Each elf's personal inventory is separated from the other elves' inventories with
// two newlines "\n\n", and each snack is separated by a single newline "\n".
// In other words, the input string is a list of elf inventories, which is itself a
// list of snacks' caloric values.
fn parse_day_01() {
  assert Ok(input) = file.read("./src/days/01.txt")

  input
  |> string.split(on: "\n\n")
  |> list.map(fn(inventory) {
    inventory
    |> string.split(on: "\n")
    |> list.filter_map(int.parse)
    |> int.sum
  })
}

pub fn part_one() {
  parse_day_01()
  |> list.fold(0, int.max)
}

pub fn part_two() {
  parse_day_01()
  |> list.sort(int.compare)
  |> list.reverse
  |> list.take(3)
  |> int.sum
}