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|
import adglent.{First, Second}
import gleam/bool
import gleam/function
import gleam/int
import gleam/io
import gleam/list
import gleam/order.{type Order, Eq, Lt}
import gleam/string
// Types -------------------------------------------------------------------------------------------
type Hand {
Hand(cards: List(Int), wager: Int)
}
type HandType {
FiveOfAKind
FourOfAKind
FullHouse
ThreeOfAKind
TwoPair
OnePair
HighCard
Unknown
}
// Common functions --------------------------------------------------------------------------------
fn hand_rank(hand_rank: HandType) -> Int {
case hand_rank {
HighCard -> 1
OnePair -> 2
TwoPair -> 3
ThreeOfAKind -> 4
FullHouse -> 5
FourOfAKind -> 6
FiveOfAKind -> 7
Unknown -> 100
}
}
fn card_rank(card: String) -> Int {
case int.parse(card), card {
Ok(n), _ -> n
_, "A" -> 14
_, "K" -> 13
_, "Q" -> 12
_, "J" -> 11
_, "T" -> 10
_, "*" -> 1
}
}
fn parse_hand(str: String) -> Hand {
let [cards, wager] = string.split(str, " ")
let cards =
string.to_graphemes(cards)
|> list.map(card_rank)
let assert Ok(wager) = int.parse(wager)
Hand(cards, wager)
}
fn card_counts(hand: Hand) {
hand.cards
|> list.sort(int.compare)
|> list.chunk(function.identity)
|> list.map(list.length)
|> list.sort(int.compare)
}
fn classify_hand(hand: Hand) -> HandType {
case list.length(list.unique(hand.cards)), card_counts(hand) {
1, _ -> FiveOfAKind
2, [1, 4] -> FourOfAKind
2, [2, 3] -> FullHouse
3, [1, 1, 3] -> ThreeOfAKind
3, [1, 2, 2] -> TwoPair
4, _ -> OnePair
5, _ -> HighCard
_, _ -> Unknown
}
}
// Part 1 ------------------------------------------------------------------------------------------
pub fn part1(input: String) {
input
|> string.split("\n")
|> list.map(parse_hand)
|> list.sort(compare_hands)
|> list.index_map(fn(i, h) { { i + 1 } * h.wager })
|> int.sum
|> string.inspect
}
fn compare_hands(hand1: Hand, hand2: Hand) -> Order {
case
int.compare(
hand_rank(classify_hand(hand1)),
hand_rank(classify_hand(hand2)),
)
{
Eq -> compare_top_card(hand1.cards, hand2.cards)
other -> other
}
}
fn compare_top_card(cards1: List(Int), cards2: List(Int)) -> Order {
use <- bool.guard(cards1 == [] || cards2 == [], Eq)
let [c1, ..rest1] = cards1
let [c2, ..rest2] = cards2
case int.compare(c1, c2) {
Eq -> compare_top_card(rest1, rest2)
other -> other
}
}
// Part 2 ------------------------------------------------------------------------------------------
pub fn part2(input: String) {
input
|> string.replace("J", "*")
|> string.split("\n")
|> list.map(parse_hand)
|> list.sort(compare_hands_considering_jokers)
|> list.index_map(fn(i, h) { { i + 1 } * h.wager })
|> int.sum
|> string.inspect
}
const card_subs = [2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14]
fn find_best_joker_substitution(hand: Hand) {
use acc, card <- list.fold(card_subs, Hand([2, 3, 4, 5, 6], 0))
let subbed_cards =
list.map(
hand.cards,
fn(c) {
case c {
1 -> card
other -> other
}
},
)
let subbed_hand = Hand(..hand, cards: subbed_cards)
case compare_hands(acc, subbed_hand) {
Lt -> subbed_hand
_ -> acc
}
}
fn compare_hands_considering_jokers(hand1: Hand, hand2: Hand) -> Order {
case
int.compare(
hand1
|> find_best_joker_substitution
|> classify_hand
|> hand_rank,
hand2
|> find_best_joker_substitution
|> classify_hand
|> hand_rank,
)
{
Eq -> compare_top_card(hand1.cards, hand2.cards)
other -> other
}
}
pub fn main() {
let assert Ok(part) = adglent.get_part()
let assert Ok(input) = adglent.get_input("7")
case part {
First ->
part1(input)
|> adglent.inspect
|> io.println
Second ->
part2(input)
|> adglent.inspect
|> io.println
}
}
|
