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|
import gleam/io
import gleam/int
import gleam/list
import gleam/bool
import gleam/pair
import gleam/string as str
import gleam/dict.{type Dict}
import ext/resultx as resx
import ext/genericx as genx
import util/input_util
import util/parser as p
type Range {
Range(min: Int, max: Int)
}
type Rule =
List(Range)
type Ticket =
List(Int)
type Notes {
Notes(
fields: Dict(String, Rule),
your_ticket: Ticket,
nearby_tickets: List(Ticket),
)
}
fn parse_notes(input: String) -> Notes {
let range_parser =
p.int()
|> p.skip(p.literal("-"))
|> p.then(p.int())
|> p.map2(with: Range)
|> p.labeled(with: "range")
let rule_parser =
range_parser
|> p.sep1(by: p.literal(" or "))
|> p.labeled(with: "rule")
let field_parser =
p.str_of_many1(of: p.gc_not_in(":"))
|> p.skip(p.literal(": "))
|> p.then(rule_parser)
|> p.labeled(with: "field")
let ticket_parser =
p.int()
|> p.sep1(by: p.literal(","))
|> p.labeled(with: "ticket")
let notes_parser =
field_parser
|> p.sep1(by: p.nl())
|> p.map(with: dict.from_list)
|> p.skip(p.nlnl())
|> p.skip(p.literal("your ticket:"))
|> p.skip(p.nl())
|> p.then(ticket_parser)
|> p.skip(p.nlnl())
|> p.skip(p.literal("nearby tickets:"))
|> p.skip(p.nl())
|> p.then_3rd(p.sep1(ticket_parser, by: p.nl()))
|> p.skip_ws()
|> p.map3(with: Notes)
|> p.labeled(with: "notes")
input
|> p.parse_entire(with: notes_parser)
|> resx.assert_unwrap
}
fn satisfies_range(value: Int, range: Range) -> Bool {
range.min <= value && value <= range.max
}
fn satisfies_rule(value: Int, rule: Rule) -> Bool {
list.any(in: rule, satisfying: satisfies_range(value, _))
}
type Column {
Collapsed(String)
Pending(List(String))
}
fn collapse_columns(columns: List(Column)) -> List(String) {
case
list.find_map(in: columns, with: fn(column) {
case column {
Pending([name]) -> Ok(name)
_ -> Error(Nil)
}
})
{
Ok(target) ->
columns
|> list.map(with: fn(column) {
case column {
Collapsed(name) -> Collapsed(name)
Pending([_]) -> Collapsed(target)
Pending(names) ->
names
|> list.filter(keeping: genx.different(_, than: target))
|> Pending
}
})
|> collapse_columns
Error(Nil) ->
columns
|> list.map(with: fn(column) {
let assert Collapsed(name) = column
name
})
}
}
fn part1(input: String) -> Int {
let notes = parse_notes(input)
notes.nearby_tickets
|> list.flatten
|> list.filter(keeping: fn(value) {
notes.fields
|> dict.values
|> list.any(satisfying: satisfies_rule(value, _))
|> bool.negate
})
|> int.sum
}
fn part2(input: String) -> Int {
let notes = parse_notes(input)
[notes.your_ticket, ..notes.nearby_tickets]
|> list.filter(keeping: fn(ticket) {
list.all(in: ticket, satisfying: fn(value) {
notes.fields
|> dict.values
|> list.any(satisfying: satisfies_rule(value, _))
})
})
|> list.transpose
|> list.map(with: fn(column) {
notes.fields
|> dict.to_list
|> list.filter_map(with: fn(entry) {
let #(name, rule) = entry
case list.all(in: column, satisfying: satisfies_rule(_, rule)) {
True -> Ok(name)
False -> Error(Nil)
}
})
|> Pending
})
|> collapse_columns
|> list.strict_zip(notes.your_ticket)
|> resx.assert_unwrap
|> list.filter(fn(entry) {
let #(column, _) = entry
str.starts_with(column, "departure")
})
|> list.map(with: pair.second)
|> int.product
}
pub fn main() -> Nil {
let testing = input_util.read_text("test16")
let assert 71 = part1(testing)
let assert 1 = part2(testing)
let input = input_util.read_text("day16")
io.debug(part1(input))
io.debug(part2(input))
Nil
}
|
