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import gleam/io
import gleam/int
import gleam/list
import gleam/pair
import gleam/string as str
import gleam/set.{type Set}
import gleam/dict.{type Dict}
import ext/setx
import ext/boolx
import ext/resultx as resx
import util/input_util
import util/parser as p
type Ingredient =
String
type Allergen =
String
type Food {
Food(ingredients: Set(Ingredient), some_allergens: Set(Allergen))
}
type Candidates =
Dict(Allergen, Set(Ingredient))
fn parse_food(text: String) -> Food {
let food_parser =
p.alpha1()
|> p.sep1(by: p.ws_gc())
|> p.map(with: set.from_list)
|> p.skip(p.literal(" (contains "))
|> p.then(
p.alpha1()
|> p.sep1(by: p.literal(", "))
|> p.map(with: set.from_list),
)
|> p.skip(p.literal(")"))
|> p.map2(with: Food)
text
|> p.parse_entire(with: food_parser)
|> resx.assert_unwrap
}
fn allergen_candidates(foods: List(Food)) -> Candidates {
foods
|> list.map(fn(f) { f.some_allergens })
|> setx.arbitrary_union
|> set.to_list
|> list.map(with: fn(allergen) {
#(
allergen,
foods
|> list.filter(keeping: fn(f) {
set.contains(in: f.some_allergens, this: allergen)
})
|> list.map(with: fn(f) { f.ingredients })
|> setx.arbitrary_intersection,
)
})
|> dict.from_list
}
fn stabilize(candidates: Candidates) -> Dict(Allergen, Ingredient) {
let is_stable = fn(s) { set.size(s) == 1 }
use <- boolx.guard_lazy(
when: candidates
|> dict.values
|> list.all(satisfying: is_stable),
return: fn() {
candidates
|> dict.map_values(with: fn(_, ingredients) {
let assert [ingredient] = set.to_list(ingredients)
ingredient
})
},
)
let stable_set =
candidates
|> dict.to_list
|> list.filter_map(with: fn(entry) {
let #(_, ingredients) = entry
case set.to_list(ingredients) {
[stable] -> Ok(stable)
_ -> Error(Nil)
}
})
|> set.from_list
candidates
|> dict.map_values(with: fn(_, ingredients) {
case is_stable(ingredients) {
True -> ingredients
False -> setx.subtract(from: ingredients, given: stable_set)
}
})
|> stabilize
}
fn part1(lines: List(String)) -> Int {
let foods = list.map(lines, with: parse_food)
let all_ingredients =
foods
|> list.map(fn(f) { f.ingredients })
|> setx.arbitrary_union
let candidates = allergen_candidates(foods)
let suspicious_ingredients =
candidates
|> dict.values
|> setx.arbitrary_union
let safe_ingredients =
setx.subtract(from: all_ingredients, given: suspicious_ingredients)
foods
|> list.map(with: fn(f) {
setx.count(f.ingredients, satisfying: set.contains(safe_ingredients, _))
})
|> int.sum
}
fn part2(lines: List(String)) -> String {
lines
|> list.map(with: parse_food)
|> allergen_candidates
|> stabilize
|> dict.to_list
|> list.sort(by: fn(a, b) { str.compare(pair.first(a), pair.first(b)) })
|> list.map(with: pair.second)
|> str.join(",")
}
pub fn main() -> Nil {
let testing = input_util.read_lines("test21")
let assert 5 = part1(testing)
let assert "mxmxvkd,sqjhc,fvjkl" = part2(testing)
let input = input_util.read_lines("day21")
io.debug(part1(input))
io.println(part2(input))
Nil
}
|
