import re
import argparse
import itertools
from enum import Enum

rule_jokers_enabled = False

class CardType(Enum):
    HighCard = 1
    OnePair = 2
    TwoPair = 3
    ThreeOfAKind = 4
    FullHouse = 5
    FourOfAKind = 6
    FiveOfAKind = 7

class Hand:
    def __init__(self,cards:str,bid:int) -> None:
        self.cards = cards
        self.bid = int(bid)
        if rule_jokers_enabled:
            self.type = self._find_type_joker(cards)
        else:
            self.type = self._find_type(cards)

    def _find_type(self,cards:str) -> CardType:
        # group cards based on card counts
        card_list = [*cards]
        card_list.sort()
        grouping = itertools.groupby(card_list,lambda x:x)
        lengths = [len(list(x[1])) for x in grouping]
        if 5 in lengths:
            return CardType.FiveOfAKind
        if 4 in lengths:
            return CardType.FourOfAKind
        if 3 in lengths and 2 in lengths:
            return CardType.FullHouse
        if 3 in lengths:
            return CardType.ThreeOfAKind
        if len([x for x in lengths if x == 2]) == 2:
            return CardType.TwoPair
        if 2 in lengths:
            return CardType.OnePair
        return CardType.HighCard
    
    def _find_type_joker(self,cards:str) -> CardType:
        try:
            joker_i = cards.index("J") 
        except ValueError:
            return self._find_type(cards)
        
        current_value = CardType.HighCard
        for new_card in [*(valid_card_list())]:
            if new_card == "J":
                continue
            test_cards = list(cards)
            test_cards[joker_i] = new_card
            new_value = self._find_type_joker("".join(test_cards))
            if new_value.value > current_value.value:
                current_value = new_value
        
        return current_value

    
    def sort_string(self):
        v = str(self.type.value) + ":" + "".join(["abcdefghijklmnoZ"[card_value(x)] for x in [*self.cards]])
        return v
    
    def __repr__(self) -> str:
        return f""



def valid_card_list() -> str:
    if rule_jokers_enabled:
        return "J23456789TQKA"
    return "23456789TJQKA"

def card_value(char:chr):
    return valid_card_list().index(char)

def main(line_list: list):
    hand_list = list()
    for l in line_list:
        card,bid = re.split(' +',l)
        hand = Hand(card,bid)
        hand_list.append(hand)
        #print(hand.sort_string())
    
    hand_list.sort(key=lambda x: x.sort_string())
    print(hand_list)

    rank_total = 0
    rank = 1
    for single_hand in hand_list:
        rank_total += rank * single_hand.bid
        rank += 1
    
    print(f"total {rank_total}")

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="day 1 solver")
    parser.add_argument("-input",type=str)
    parser.add_argument("-part",type=int)
    args = parser.parse_args()

    if args.part == 2:
        rule_jokers_enabled = True

    filename = args.input
    if filename == None:
        parser.print_help()
        exit(1)
    file = open(filename,'r')
    main([line.rstrip('\n') for line in file.readlines()])
    file.close()

public class Day7Task1:IRunnable {

public static Dictionary CardValues = new Dictionary()
 {
     { '2', "01" },
     { '3', "02" },
     { '4', "03" },
     { '5', "04" },
     { '6', "05" },
     { '7', "06" },
     { '8', "07" },
     { '9', "08" },
     { 'T', "09" },
     { 'J', "10" },
     { 'Q', "11" },
     { 'K', "12" },
     { 'A', "13" }
 };
 
 public void Run()
 {
     //var inputLines = File.ReadAllLines("Days/Seven/Day7ExampleInput.txt");
     var inputLines = File.ReadAllLines("Days/Seven/Day7Input.txt");



     var hands = inputLines.Select(line =>
     {
         var split = line.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
         return new Hand(split[0],  split[1] );
     }).ToList();

     var sortedHands = hands.OrderBy(hand => hand.Score).ToList();

     long resultValue = 0;

     for (int i = 1; i < hands.Count()+1; i++)
     {
         resultValue += i * sortedHands[i-1].Bid;
     }

     Console.WriteLine("Result:" + resultValue);

 }

 public class Hand
 {
     public Hand(string cards, string bid)
     {
         Cards = cards;
         Bid = int.Parse(bid);
         Score = GenerateScore();
     }

     public string Cards { get; set; }
     public int Bid { get; set; }
     
     public long Score { get; }

     private long GenerateScore()
     {
         var resultString = new StringBuilder();
         var cardGroups = Cards.GroupBy(c => c).ToList();
         var groupCounts = cardGroups.OrderByDescending(g => g.Count()).Select(g => g.Count()).ToList();
         if (cardGroups.Count() == 1)
         {
             resultString.Append("7");
         }
         else if(cardGroups.Count() == 2 && (cardGroups[0].Count() == 4 || cardGroups[0].Count() == 1))
         {
             resultString.Append("6");
         }
         else if(cardGroups.Count() == 2 && (cardGroups[0].Count() == 3 || cardGroups[0].Count() == 2))
         {
             resultString.Append("5");
         }
         else if(cardGroups.Count() == 3 && (cardGroups[0].Count() == 3 || cardGroups[1].Count() == 3 || cardGroups[2].Count() == 3))
         {
             resultString.Append("4");
         }
         else if(cardGroups.Count() == 3 && groupCounts[0] == 2 && groupCounts[1] == 2 && groupCounts[2] == 1)
         {
             resultString.Append("3");
         }
         else if(cardGroups.Count() == 4 )
         {
             resultString.Append("2");
         }
         else
         {
             resultString.Append("1");
         }

         foreach (var card in Cards)
         {
             resultString.Append(Day7Task1.CardValues[card]);
         }

         Console.WriteLine("Cards:{0} Score:{1}",Cards,resultString);
         return long.Parse(resultString.ToString());
     }
 }
}

public class Day7Task2:IRunnable
{
    public static Dictionary CardValues = new Dictionary()
    {
        { '2', "01" },
        { '3', "02" },
        { '4', "03" },
        { '5', "04" },
        { '6', "05" },
        { '7', "06" },
        { '8', "07" },
        { '9', "08" },
        { 'T', "09" },
        { 'J', "00" },
        { 'Q', "11" },
        { 'K', "12" },
        { 'A', "13" }
    };
    
    public void Run()
    {
        //var inputLines = File.ReadAllLines("Days/Seven/Day7ExampleInput.txt");
        var inputLines = File.ReadAllLines("Days/Seven/Day7Input.txt");



        var hands = inputLines.Select(line =>
        {
            var split = line.Split(' ', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
            return new Hand(split[0],  split[1] );
        }).ToList();

        var sortedHands = hands.OrderBy(hand => hand.Score).ToList();

        long resultValue = 0;

        for (int i = 1; i < hands.Count()+1; i++)
        {
            resultValue += i * sortedHands[i-1].Bid;
        }

        Console.WriteLine("Result:" + resultValue);

    }

    public class Hand
    {
        public Hand(string cards, string bid)
        {
            Cards = cards;
            Bid = int.Parse(bid);
            Score = GenerateScore();
        }

        public string Cards { get; set; }
        public int Bid { get; set; }
        
        public long Score { get; }

        private long GenerateScore()
        {
            var generateFirstDigit = new Func(cards =>
            {
                var cardGroups = cards.GroupBy(c => c).ToList();
                var groupCounts = cardGroups.OrderByDescending(g => g.Count()).Select(g => g.Count()).ToList();
                if (cardGroups.Count() == 1)
                {
                    return 7;
                }
                else if (cardGroups.Count() == 2 && (cardGroups[0].Count() == 4 || cardGroups[0].Count() == 1))
                {
                    return 6;
                }
                else if (cardGroups.Count() == 2 && (cardGroups[0].Count() == 3 || cardGroups[0].Count() == 2))
                {
                    return 5;
                }
                else if (cardGroups.Count() == 3 && (cardGroups[0].Count() == 3 || cardGroups[1].Count() == 3 || cardGroups[2].Count() == 3))
                {
                    return 4;
                }
                else if (cardGroups.Count() == 3 && groupCounts[0] == 2 && groupCounts[1] == 2 && groupCounts[2] == 1)
                {
                    return 3;
                }
                else if (cardGroups.Count() == 4)
                {
                    return 2;
                }
                else
                {
                    return 1;
                }
            });
            
            var resultString = new StringBuilder();

            var maxFistDigit = Day7Task2.CardValues.Keys.Select(card => generateFirstDigit(Cards.Replace('J', card))).Max();

            resultString.Append(maxFistDigit);
            
            foreach (var card in Cards)
            {
                resultString.Append(Day7Task2.CardValues[card]);
            }

            Console.WriteLine("Cards:{0} Score:{1}",Cards,resultString);
            return long.Parse(resultString.ToString());
        }
    }
}

import os

filePath = os.path.dirname(os.path.realpath(__file__))
inputFilePath = filePath + "\\adventofcode.com_2023_day_7_input.txt"
# inputFilePath = filePath + "\\part1.txt"

def typeSort(hand):
	cardCount = {
		"2": 0,
		"3": 0,
		"4": 0,
		"5": 0,
		"6": 0,
		"7": 0,
		"8": 0,
		"9": 0,
		"T": 0,
		"J": 0,
		"Q": 0,
		"K": 0,
		"A": 0
	}
	for card in hand:
		cardCount[card] += 1
	cardTotals = list(cardCount.values())
	cardTotals.sort(reverse=True)
	if(cardTotals[0] == 5):
		return 6
	elif(cardTotals[0] == 4):
		return 5
	elif(cardTotals[0] == 3 and cardTotals[1] == 2):
		return 4
	elif(cardTotals[0] == 3):
		return 3
	elif(cardTotals[0] == 2 and cardTotals[1] == 2):
		return 2
	elif(cardTotals[0] == 2):
		return 1
	else:
		return 0

def bucketSort(camelCard):
	totalScore = 0
	cardOrder = ["2","3","4","5","6","7","8","9","T","J","Q","K","A"]
	hand = camelCard[0]
	totalScore += cardOrder.index(hand[4]) * 15 ** 1
	totalScore += cardOrder.index(hand[3]) * 15 ** 2
	totalScore += cardOrder.index(hand[2]) * 15 ** 3
	totalScore += cardOrder.index(hand[1]) * 15 ** 4
	totalScore += cardOrder.index(hand[0]) * 15 ** 5
	return totalScore

hands = []
bids = []

with open(inputFilePath) as inputFile:
	for line in inputFile:
		lineSplit = line.split()
		hand = lineSplit[0]
		bid = lineSplit[1]
		hands.append(hand)
		bids.append(bid)

bids = [int(bid) for bid in bids]

camelCards = list(zip(hands,bids))

typeBuckets = [[],[],[],[],[],[],[]]

for camelCard in camelCards:
	hand = camelCard[0]
	typeScore = typeSort(hand)
	typeBuckets[typeScore].append(camelCard)

finalCardSort = []

for bucket in typeBuckets:
	if(len(bucket) > 1):
		bucket.sort(key=bucketSort)
	for camelCard in bucket:
		finalCardSort.append(camelCard)

camelScores = []

for camelIndex in range(len(finalCardSort)):
	scoreMultiplier = camelIndex + 1
	camelCard = finalCardSort[camelIndex]
	camelScores.append(camelCard[1] * scoreMultiplier)

print(sum(camelScores))

import os

filePath = os.path.dirname(os.path.realpath(__file__))
inputFilePath = filePath + "\\adventofcode.com_2023_day_7_input.txt"
# inputFilePath = filePath + "\\part1.txt"

def typeSort(hand):
	cardCount = {
		"J": 0,
		"2": 0,
		"3": 0,
		"4": 0,
		"5": 0,
		"6": 0,
		"7": 0,
		"8": 0,
		"9": 0,
		"T": 0,
		"Q": 0,
		"K": 0,
		"A": 0
	}
	for card in hand:
		cardCount[card] += 1
	jokerCount = cardCount["J"]
	cardCount["J"] = 0
	cardTotals = list(cardCount.values())
	cardTotals.sort(reverse=True)
	if(cardTotals[0] + jokerCount == 5):
		return 6
	elif(cardTotals[0] + jokerCount == 4):
		return 5
	elif(
		cardTotals[0] + jokerCount == 3 and cardTotals[1] == 2
		or cardTotals[0] == 3 and cardTotals[1] + jokerCount == 2
	):
		return 4
	elif(cardTotals[0] + jokerCount == 3):
		return 3
	elif(
		cardTotals[0] + jokerCount == 2 and cardTotals[1] == 2
		or cardTotals[0] == 2 and cardTotals[1] + jokerCount == 2
	):
		return 2
	elif(cardTotals[0] + jokerCount == 2):
		return 1
	else:
		return 0

def bucketSort(camelCard):
	totalScore = 0
	cardOrder = ["J","2","3","4","5","6","7","8","9","T","Q","K","A"]
	hand = camelCard[0]
	totalScore += cardOrder.index(hand[4]) * 15 ** 1
	totalScore += cardOrder.index(hand[3]) * 15 ** 2
	totalScore += cardOrder.index(hand[2]) * 15 ** 3
	totalScore += cardOrder.index(hand[1]) * 15 ** 4
	totalScore += cardOrder.index(hand[0]) * 15 ** 5
	return totalScore

hands = []
bids = []

with open(inputFilePath) as inputFile:
	for line in inputFile:
		lineSplit = line.split()
		hand = lineSplit[0]
		bid = lineSplit[1]
		hands.append(hand)
		bids.append(bid)

bids = [int(bid) for bid in bids]

camelCards = list(zip(hands,bids))

typeBuckets = [[],[],[],[],[],[],[]]

for camelCard in camelCards:
	hand = camelCard[0]
	typeScore = typeSort(hand)
	typeBuckets[typeScore].append(camelCard)

finalCardSort = []

for bucket in typeBuckets:
	if(len(bucket) > 1):
		bucket.sort(key=bucketSort)
	for camelCard in bucket:
		finalCardSort.append(camelCard)

camelScores = []

for camelIndex in range(len(finalCardSort)):
	scoreMultiplier = camelIndex + 1
	camelCard = finalCardSort[camelIndex]
	camelScores.append(camelCard[1] * scoreMultiplier)

print(sum(camelScores))

import os

filePath = os.path.dirname(os.path.realpath(__file__))
inputFilePath = filePath + "\\adventofcode.com_2023_day_7_input.txt"
# inputFilePath = filePath + "\\part1.txt"

CARD_ORDER = "23456789TJQKA"

def typeSort(camelCard):
	cardCount = {}
	for card in CARD_ORDER:
		cardCount[card] = 0
	hand = camelCard[0]
	for card in hand:
		cardCount[card] += 1
	cardTotals = list(cardCount.values())
	cardTotals.sort(reverse=True)
	if(cardTotals[0] == 5):
		return 6
	elif(cardTotals[0] == 4):
		return 5
	elif(cardTotals[0] == 3 and cardTotals[1] == 2):
		return 4
	elif(cardTotals[0] == 3):
		return 3
	elif(cardTotals[0] == 2 and cardTotals[1] == 2):
		return 2
	elif(cardTotals[0] == 2):
		return 1
	else:
		return 0

def handSort(camelCard):
	totalScore = 0
	hand = camelCard[0]
	totalScore += CARD_ORDER.index(hand[4]) * 15 ** 1
	totalScore += CARD_ORDER.index(hand[3]) * 15 ** 2
	totalScore += CARD_ORDER.index(hand[2]) * 15 ** 3
	totalScore += CARD_ORDER.index(hand[1]) * 15 ** 4
	totalScore += CARD_ORDER.index(hand[0]) * 15 ** 5
	return totalScore

hands = []
bids = []

with open(inputFilePath) as inputFile:
	for line in inputFile:
		lineSplit = line.split()
		hand = lineSplit[0]
		bid = lineSplit[1]
		hands.append(hand)
		bids.append(int(bid))

camelCards = list(zip(hands,bids))
camelCards = sorted(camelCards, key=lambda x: (typeSort(x), handSort(x)))

camelScores = []

for camelIndex in range(len(camelCards)):
	scoreMultiplier = camelIndex + 1
	camelCard = camelCards[camelIndex]
	camelScores.append(camelCard[1] * scoreMultiplier)

print(sum(camelScores))

import os

filePath = os.path.dirname(os.path.realpath(__file__))
inputFilePath = filePath + "\\adventofcode.com_2023_day_7_input.txt"
# inputFilePath = filePath + "\\part1.txt"

CARD_ORDER = "J23456789TQKA"

def typeSort(camelCard):
	cardCount = {}
	for card in CARD_ORDER:
		cardCount[card] = 0
	hand = camelCard[0]
	for card in hand:
		cardCount[card] += 1
	jokerCount = cardCount["J"]
	cardCount["J"] = 0
	cardTotals = list(cardCount.values())
	cardTotals.sort(reverse=True)
	if(cardTotals[0] + jokerCount == 5):
		return 6
	elif(cardTotals[0] + jokerCount == 4):
		return 5
	elif(
		cardTotals[0] + jokerCount == 3 and cardTotals[1] == 2
		or cardTotals[0] == 3 and cardTotals[1] + jokerCount == 2
	):
		return 4
	elif(cardTotals[0] + jokerCount == 3):
		return 3
	elif(
		cardTotals[0] + jokerCount == 2 and cardTotals[1] == 2
		or cardTotals[0] == 2 and cardTotals[1] + jokerCount == 2
	):
		return 2
	elif(cardTotals[0] + jokerCount == 2):
		return 1
	else:
		return 0

def handSort(camelCard):
	totalScore = 0
	hand = camelCard[0]
	totalScore += CARD_ORDER.index(hand[4]) * 15 ** 1
	totalScore += CARD_ORDER.index(hand[3]) * 15 ** 2
	totalScore += CARD_ORDER.index(hand[2]) * 15 ** 3
	totalScore += CARD_ORDER.index(hand[1]) * 15 ** 4
	totalScore += CARD_ORDER.index(hand[0]) * 15 ** 5
	return totalScore

hands = []
bids = []

with open(inputFilePath) as inputFile:
	for line in inputFile:
		lineSplit = line.split()
		hand = lineSplit[0]
		bid = lineSplit[1]
		hands.append(hand)
		bids.append(int(bid))

camelCards = list(zip(hands,bids))
camelCards = sorted(camelCards, key=lambda x: (typeSort(x), handSort(x)))

camelScores = []

for camelIndex in range(len(camelCards)):
	scoreMultiplier = camelIndex + 1
	camelCard = camelCards[camelIndex]
	camelScores.append(camelCard[1] * scoreMultiplier)

print(sum(camelScores))

This was pretty straightforward: create a histogram of the cards in each hand to determine their type, and if there is a tie-breaker, compare each card pairwise. I use the Counter class from collections to do the counting, and then had a dictionary/table to convert labels to numeric values for comparison. I used a very OOP approach and wrote a magic method for comparing hands and used that with Python’s builtin sort. I even got to use Enum!

LABELS = {l: v for v, l in enumerate('23456789TJQKA', 2)}

class HandType(IntEnum):
    FIVE_OF_A_KIND  = 6
    FOUR_OF_A_KIND  = 5
    FULL_HOUSE      = 4
    THREE_OF_A_KIND = 3
    TWO_PAIR        = 2
    ONE_PAIR        = 1
    HIGH_CARD       = 0

class Hand:
    def __init__(self, cards=str, bid=str):
        self.cards  = cards
        self.bid    = int(bid)
        counts      = Counter(self.cards)
        self.type   = (
            HandType.FIVE_OF_A_KIND  if len(counts) == 1 else
            HandType.FOUR_OF_A_KIND  if len(counts) == 2 and any(l for l, count in counts.items() if count == 4) else
            HandType.FULL_HOUSE      if len(counts) == 2 and any(l for l, count in counts.items() if count == 3) else
            HandType.THREE_OF_A_KIND if len(counts) == 3 and any(l for l, count in counts.items() if count == 3) else
            HandType.TWO_PAIR        if len(counts) == 3 and any(l for l, count in counts.items() if count == 2) else
            HandType.ONE_PAIR        if len(counts) == 4 and any(l for l, count in counts.items() if count == 2) else
            HandType.HIGH_CARD
        )

    def __lt__(self, other):
        if self.type == other.type:
            for s_label, o_label in zip(self.cards, other.cards):
                if LABELS[s_label] == LABELS[o_label]:
                    continue
                return LABELS[s_label] < LABELS[o_label]
            return False
        return self.type < other.type

    def __repr__(self):
        return f'Hand(cards={self.cards},bid={self.bid},type={self.type})'

def read_hands(stream=sys.stdin) -> list[Hand]:
    return [Hand(*line.split()) for line in stream]

def main(stream=sys.stdin) -> None:
    hands    = sorted(read_hands(stream))
    winnings = sum(rank * hand.bid for rank, hand in enumerate(hands, 1))
    print(winnings)

For the second part, I just had to add some post-processing code to convert the jokers into actual cards. The key insight is to find the highest and most numerous non-Joker card and convert all the Jokers to that card label.

This had two edge cases that tripped me up:

1. ‘JJJJJ’: There is no other non-Joker here, so I messed up and ranked this the lowest because I ended up removing all counts.

2. ‘JJJ12’: This also messed me up b/c the Joker was the most numerous card, and I didn’t handle that properly.

Once I fixed the post-processing code though, everything else remained the same. Below, I only show the parts that changed from Part A.

LABELS = {l: v for v, l in enumerate('J23456789TQKA', 1)}

...

class Hand:
    def __init__(self, cards=str, bid=str):
        self.cards  = cards
        self.bid    = int(bid)
        counts      = Counter(self.cards)

        if 'J' in counts and len(counts) > 1:
            max_label = max(set(counts) - {'J'}, key=lambda l: (counts[l], LABELS[l]))
            counts[max_label] += counts['J']
            del counts['J']

        self.type   = (...)

input = File.read("input.txt").lines
rank = {
	'J' => 1,
	'2' => 2,
	'3' => 3,
	'4' => 4,
	'5' => 5,
	'6' => 6,
	'7' => 7,
	'8' => 8,	
	'9' => 9,
	'T' => 10,
	# 'J' => 11,
	'Q' => 12,
	'K' => 13,
	'A' => 14
}

hand = input.map do |line|
	split = line.split
	weights = split[0].chars.map {|c| rank[c]}
	{weights, split[1].to_i}
end

hand.sort! do |a, b|
	a_rank = get_rank(a[0], true)
	b_rank = get_rank(b[0], true)
	
	# puts "#{a}-#{a_rank} #{b}-#{b_rank}"
	next  1 if a_rank > b_rank
	next -1 if b_rank > a_rank

	val = 0
	5.times do |i| 
		val =  1 if a[0][i] > b[0][i]
		val = -1 if b[0][i] > a[0][i]
		break unless val == 0
	end
	val
end

sum = 0
hand.each_with_index do |card, i|
	sum += card[1]*(i+1)
end
puts sum


def get_rank(card : Array(Int32), joker = false ) : Float64 | Int32
	aa = card.uniq

	if joker
		card = aa.map { |c|
			combo = card.map {|a| a == 1 ? c : a }
			{combo, get_rank(combo)}
		}.max_by {|a| a[1]}[0]
		aa = card.uniq
	end
	
	rank = 6 - aa.size
	case rank
	when 3
		return 3.5 if card.count(aa[0]) == 3
		return 3   if card.count(aa[0]) == 2
		return 3   if card.count(aa[1]) == 2
		return 3.5
	when 4
		return 4 if card.count(aa[0]) == 3 || card.count(aa[0]) == 2
		return 4.5
	else 
		return rank
	end
end

it doesn’t make any sense to pick different cards for the jokers, and that it’s always the highest score to assign all jokers to the most frequent card.

inductive Card
  | two
  | three
  | four
  | five
  | six
  | seven
  | eight
  | nine
  | ten
  | jack
  | queen
  | king
  | ace
  deriving Repr, Ord, BEq

inductive Hand
  | mk : Card → Card → Card → Card → Card → Hand
  deriving Repr, BEq

private inductive Score
  | highCard
  | onePair
  | twoPair
  | threeOfAKind
  | fullHouse
  | fourOfAKind
  | fiveOfAKind
  deriving Repr, Ord, BEq

-- we need countCards in part 2 again, but there it has different types
private class CardList (η : Type) (χ : outParam Type) where
  cardList : η → List χ

-- similarly, we can implement Ord in terms of CardList and Score
private class Scorable (η : Type) where
  score : η → Score

private instance : CardList Hand Card where
  cardList := λ
    | .mk a b c d e => [a,b,c,d,e]

private def countCards {η χ : Type} (input :η) [CardList η χ] [Ord χ] [BEq χ] : List (Nat × χ) :=
  let ordered := (CardList.cardList input).quicksort
  let helper := λ (a : List (Nat × χ)) (c : χ) ↦ match a with
  | [] => [(1, c)]
  | a :: as =>
    if a.snd == c then
      (a.fst + 1, c) :: as
    else
      (1, c) :: a :: as
  List.quicksortBy (·.fst > ·.fst) $ ordered.foldl helper []

private def evaluateCountedCards : (l : List (Nat × α)) → Score
  | [_] => Score.fiveOfAKind -- only one entry means all cards are equal
  | (4,_) :: _ => Score.fourOfAKind
  | [(3,_), (2,_)] => Score.fullHouse
  | (3,_) :: _ => Score.threeOfAKind
  | [(2,_), (2,_), _] => Score.twoPair
  | (2,_) :: _ => Score.onePair
  | _ => Score.highCard

private def Hand.score (hand : Hand) : Score :=
  evaluateCountedCards $ countCards hand

private instance : Scorable Hand where
  score := Hand.score

instance {σ χ : Type} [Scorable σ] [CardList σ χ] [Ord χ] : Ord σ where
  compare (a b : σ) :=
    let comparedScores := Ord.compare (Scorable.score a) (Scorable.score b)
    if comparedScores != Ordering.eq then
      comparedScores
    else
      Ord.compare (CardList.cardList a) (CardList.cardList b)

private def Card.fromChar? : Char → Option Card
| '2' => some Card.two
| '3' => some Card.three
| '4' => some Card.four
| '5' => some Card.five
| '6' => some Card.six
| '7' => some Card.seven
| '8' => some Card.eight
| '9' => some Card.nine
| 'T' => some Card.ten
| 'J' => some Card.jack
| 'Q' => some Card.queen
| 'K' => some Card.king
| 'A' => some Card.ace
| _ => none

private def Hand.fromString? (input : String) : Option Hand :=
  match input.toList.mapM Card.fromChar? with
  | some [a, b, c, d, e] => Hand.mk a b c d e
  | _ => none

abbrev Bet := Nat

structure Player where
  hand : Hand
  bet : Bet
  deriving Repr

def parse (input : String) : Except String (List Player) := do
  let lines := input.splitOn "\n" |> List.map String.trim |> List.filter String.notEmpty
  let parseLine := λ (line : String) ↦
    if let [hand, bid] := line.split Char.isWhitespace |> List.map String.trim |> List.filter String.notEmpty then
      Option.zip (Hand.fromString? hand) (String.toNat? bid)
      |> Option.map (uncurry Player.mk)
      |> Option.toExcept s!"Line could not be parsed: {line}"
    else
      throw s!"Failed to parse. Line did not separate into hand and bid properly: {line}"
  lines.mapM parseLine

def part1 (players : List Player) : Nat :=
  players.quicksortBy (λ p q ↦ p.hand < q.hand)
  |> List.enumFrom 1
  |> List.foldl (λ r p ↦ p.fst * p.snd.bet + r) 0


------------------------------------------------------------------------------------------------------
-- Again a riddle where part 2 needs different data representation, why are you doing this to me? Why?
-- (Though, strictly speaking, I could just add "joker" to the list of cards in part 1 and treat it special)

private inductive Card2
  | joker
  | two
  | three
  | four
  | five
  | six
  | seven
  | eight
  | nine
  | ten
  | queen
  | king
  | ace
  deriving Repr, Ord, BEq

private def Card.toCard2 : Card → Card2
  | .two => Card2.two
  | .three => Card2.three
  | .four => Card2.four
  | .five => Card2.five
  | .six => Card2.six
  | .seven => Card2.seven
  | .eight => Card2.eight
  | .nine => Card2.nine
  | .ten => Card2.ten
  | .jack => Card2.joker
  | .queen => Card2.queen
  | .king => Card2.king
  | .ace => Card2.ace

private inductive Hand2
  | mk : Card2 → Card2 → Card2 → Card2 → Card2 → Hand2
  deriving Repr

private def Hand.toHand2 : Hand → Hand2
  | Hand.mk a b c d e => Hand2.mk a.toCard2 b.toCard2 c.toCard2 d.toCard2 e.toCard2

instance : CardList Hand2 Card2 where
  cardList := λ
    | .mk a b c d e => [a,b,c,d,e]

private def Hand2.score (hand : Hand2) : Score :=
  -- I could be dumb here and just let jokers be any other card, but that would be really wasteful
  -- Also, I'm pretty sure there is no combination that would benefit from jokers being mapped to
  -- different cards.
  -- and, even more important, I think we can always map jokers to the most frequent card and are
  -- still correct.
  let counted := countCards hand
  let (jokers, others) := counted.partition λ e ↦ e.snd == Card2.joker
  let jokersReplaced := match jokers, others with
  | (jokers, _) :: _ , (a, ac) :: as => (a+jokers, ac) :: as
  | _ :: _, [] => jokers
  | [], others => others
  evaluateCountedCards jokersReplaced

private instance : Scorable Hand2 where
  score := Hand2.score

private structure Player2 where
  bet : Bet
  hand2 : Hand2

def part2 (players : List Player) : Nat :=
  let players := players.map λ p ↦
    {bet := p.bet, hand2 := p.hand.toHand2 : Player2}
  players.quicksortBy (λ p q ↦ p.hand2 < q.hand2)
  |> List.enumFrom 1
  |> List.foldl (λ r p ↦ p.fst * p.snd.bet + r) 0