Done in C# Input parsing done with a mixture of splits and Regex (no idea why everyone hates it?) capture groups.

I have overbuilt for both days, but not tripped on any of the ‘traps’ in the input data - generally expecting the input to be worse than it is… too used to actual data from users

    public Day2RoundInput(string gameString)
    {
        var colonSplit = gameString.Trim().Split(':', StringSplitOptions.RemoveEmptyEntries);
        var match = gameNumRegex.Match(colonSplit[0].Trim());
        var gameNumberString = match.Groups[1].Value;
        GameNumber = int.Parse(gameNumberString.Trim());

        HandfulsOfCubes = new List();
        var roundsSplit = colonSplit[1].Trim().Split(';', StringSplitOptions.RemoveEmptyEntries);
        foreach (var round in roundsSplit)
        {
            HandfulsOfCubes.Add(new HandfulCubes(round));
        }
    }
    public int GameNumber { get; set; }

    public List HandfulsOfCubes { get; set; }

    public class HandfulCubes
    {
        private Regex colourRegex = new Regex("([0-9]*) (red|green|blue)");

        public HandfulCubes(string roundString)
        {
            var colourCounts = roundString.Split(',', StringSplitOptions.RemoveEmptyEntries);
            foreach (var colour in colourCounts)
            {
                var matches = colourRegex.Matches(colour.Trim());

                foreach (Match match in matches)
                {
                    var captureOne = match.Groups[1];

                    var count = int.Parse(captureOne.Value.Trim());

                    var captureTwo = match.Groups[2];

                    switch (captureTwo.Value.Trim().ToLower())
                    {
                        case "red":
                            RedCount = count;
                            break;
                        case "green":
                            GreenCount = count;
                            break;
                        case "blue":
                            BlueCount = count;
                            break;
                        default: throw new Exception("uh oh");
                    }
                }
            }
        }

        public int RedCount { get; set; }
        public int GreenCount { get; set; }
        public int BlueCount { get; set; }
    }

}

        var maxAllowedRed = 12;
        var maxAllowedGreen = 13;
        var maxAllowedBlue = 14;

        var allowedGameIdSum = 0;

        foreach ( var game in inputs ) { 
            var maxRed = game.HandfulsOfCubes.Select(h => h.RedCount).Max();
            var maxGreen = game.HandfulsOfCubes.Select(h => h.GreenCount).Max();
            var maxBlue = game.HandfulsOfCubes.Select(h => h.BlueCount).Max();

            if ( maxRed <= maxAllowedRed && maxGreen <= maxAllowedGreen && maxBlue <= maxAllowedBlue) 
            {
                allowedGameIdSum += game.GameNumber;
                Console.WriteLine("Game:" + game.GameNumber + " allowed");
            }
            else
            {
                Console.WriteLine("Game:" + game.GameNumber + "not allowed");
            }
        }

        Console.WriteLine("Sum:" + allowedGameIdSum.ToString());

    }

    private List GetInputs()
    {
        List inputs = new List();

        var textLines = File.ReadAllLines("Days/Two/Day2Input.txt");

        foreach (var line in textLines)
        {
            inputs.Add(new Day2RoundInput(line));
        }

        return inputs;
    }

    
}

        var result = 0;

        foreach ( var game in inputs ) {
            var maxRed = game.HandfulsOfCubes.Select(h => h.RedCount).Max();
            var maxGreen = game.HandfulsOfCubes.Select(h => h.GreenCount).Max();
            var maxBlue = game.HandfulsOfCubes.Select(h => h.BlueCount).Max();

            var power = maxRed*maxGreen*maxBlue;
            Console.WriteLine("Game:" + game.GameNumber + " Result:" + power.ToString());

            result += power;
        }

        Console.WriteLine("Day2 Task2 Result:" + result.ToString());

    }

    private List GetInputs()
    {
        List inputs = new List();

        var textLines = File.ReadAllLines("Days/Two/Day2Input.txt");
        //var textLines = File.ReadAllLines("Days/Two/Day2ExampleInput.txt");

        foreach (var line in textLines)
        {
            inputs.Add(new Day2RoundInput(line));
        }

        return inputs;
    }

    
}

C# - a tad bit overkill for this. I was worried that we’d need more statistical analysis in part 2, so I designed my solution around that. I ended up cutting everything back when Max() was enough for both parts.

https://github.com/warriordog/advent-of-code-2023/tree/main/Solutions/Day02

Is anyone else like me, but it took me longer to understand what I was supposed to do on day 2 than on day 1? However, here is my solution written in Golang: https://github.com/alexruf/adventofcode2023/tree/main/d02

Rust (Rank 7421/6311) (Time after start 00:32:27/00:35:35)

Extremely easy part 2 today, I would say easier than part 1 but they share the same sort of framework

use std::fs;

fn part1(input: String) -> i32 {
    const RED: i32 = 12;
    const GREEN: i32 = 13;
    const BLUE: i32 = 14;

    let mut sum = 0;

    for line in input.lines() {
        let [id, content] = line.split(": ").collect::>()[0..2] else { continue };
        let id = id.split(" ").collect::>()[1].parse::().unwrap();

        let marbles = content.split("; ").map(|x| { x.split(", ").collect::>() }).collect::>>();
        let mut valid = true;

        for selection in marbles {
            for marble in selection {
                let marble_split = marble.split(" ").collect::>();
                let marble_amount = marble_split[0].parse::().unwrap();
                let marble_color = marble_split[1];

                if marble_color == "red" && marble_amount > RED {
                    valid = false;
                    break;
                }

                if marble_color == "green" && marble_amount > GREEN {
                    valid = false;
                    break;
                }

                if marble_color == "blue" && marble_amount > BLUE {
                    valid = false;
                    break;
                }
            }
        }

        if !valid {
            continue;
        }

        sum += id;
    }

    return sum;
}

fn part2(input: String) -> i32 {
    let mut sum = 0;

    for line in input.lines() {
        let [id, content] = line.split(": ").collect::>()[0..2] else { continue };
        let id = id.split(" ").collect::>()[1].parse::().unwrap();

        let marbles = content.split("; ").map(|x| { x.split(", ").collect::>() }).collect::>>();
        
        let mut red = 0;
        let mut green = 0;
        let mut blue = 0;

        for selection in marbles {
            for marble in selection {
                let marble_split = marble.split(" ").collect::>();
                let marble_amount = marble_split[0].parse::().unwrap();
                let marble_color = marble_split[1];

                if marble_color == "red" && marble_amount > red {
                    red = marble_amount;
                }

                if marble_color == "green" && marble_amount > green {
                    green = marble_amount;
                }

                if marble_color == "blue" && marble_amount > blue {
                    blue = marble_amount;
                }
            }
        }

        sum += red * green * blue;
    }

    return sum;
}

fn main() {
    let input = fs::read_to_string("data/input.txt").unwrap();

    println!("{}", part1(input.clone()));
    println!("{}", part2(input.clone()));
}

Code Link

Did mine in Odin. Found this day’s to be super easy, most of the challenge was just parsing.

package day2

import "core:fmt"
import "core:strings"
import "core:strconv"
import "core:unicode"

Round :: struct {
    red: int,
    green: int,
    blue: int,
}

parse_round :: proc(s: string) -> Round {
    ret: Round

    rest := s
    for {
        nextNumAt := strings.index_proc(rest, unicode.is_digit)
        if nextNumAt == -1 do break
        rest = rest[nextNumAt:]

        numlen: int
        num, ok := strconv.parse_int(rest, 10, &numlen)
        rest = rest[numlen+len(" "):]

        if rest[:3] == "red" {
            ret.red = num
        } else if rest[:4] == "blue" {
            ret.blue = num
        } else if rest[:5] == "green" {
            ret.green = num
        }
    }

    return ret
}

Game :: struct {
    id: int,
    rounds: [dynamic]Round,
}

parse_game :: proc(s: string) -> Game {
    ret: Game

    rest := s[len("Game "):]

    idOk: bool
    idLen: int
    ret.id, idOk = strconv.parse_int(rest, 10, &idLen)
    rest = rest[idLen+len(": "):]

    for len(rest) > 0 {
        endOfRound := strings.index_rune(rest, ';')
        if endOfRound == -1 do endOfRound = len(rest)

        append(&ret.rounds, parse_round(rest[:endOfRound]))
        rest = rest[min(endOfRound+1, len(rest)):]
    }

    return ret
}

is_game_possible :: proc(game: Game) -> bool {
    for round in game.rounds {
        if round.red   > 12 ||
           round.green > 13 ||
           round.blue  > 14 {
            return false
        }
    }
    return true
}

p1 :: proc(input: []string) {
    totalIds := 0

    for line in input {
        game := parse_game(line)
        defer delete(game.rounds)

        if is_game_possible(game) do totalIds += game.id
    }

    fmt.println(totalIds)
}

p2 :: proc(input: []string) {
    totalPower := 0

    for line in input {
        game := parse_game(line)
        defer delete(game.rounds)

        minRed   := 0
        minGreen := 0
        minBlue  := 0
        for round in game.rounds {
            minRed   = max(minRed  , round.red  )
            minGreen = max(minGreen, round.green)
            minBlue  = max(minBlue , round.blue )
        }

        totalPower += minRed * minGreen * minBlue
    }

    fmt.println(totalPower)
}

Python

Questions and feedback welcome!

import collections

from .solver import Solver

class Day02(Solver):
  def __init__(self):
    super().__init__(2)
    self.games = []

  def presolve(self, input: str):
    lines = input.rstrip().split('\n')
    for line in lines:
      draws = line.split(': ')[1].split('; ')
      draws = [draw.split(', ') for draw in draws]
      self.games.append(draws)

  def solve_first_star(self):
    game_id = 0
    total = 0
    for game in self.games:
      game_id += 1
      is_good = True
      for draw in game:
        for item in draw:
          count, colour = item.split(' ')
          if (colour == 'red' and int(count) > 12 or  # pylint: disable=too-many-boolean-expressions
                colour == 'blue' and int(count) > 14 or
                colour == 'green' and int(count) > 13):
            is_good = False
      if is_good:
        total += game_id
    return total

  def solve_second_star(self):
    total = 0
    for game in self.games:
      minimums = collections.defaultdict(lambda: 0)
      for draw in game:
        for item in draw:
          count, colour = item.split(' ')
          minimums[colour] = max(minimums[colour], int(count))
      power = minimums['red'] * minimums['blue'] * minimums['green']
      total += power
    return total

My solution in python

input="""Game 1: 3 blue, 4 red; 1 red, 2 green, 6 blue; 2 green
Game 2: 1 blue, 2 green; 3 green, 4 blue, 1 red; 1 green, 1 blue
Game 3: 8 green, 6 blue, 20 red; 5 blue, 4 red, 13 green; 5 green, 1 red
Game 4: 1 green, 3 red, 6 blue; 3 green, 6 red; 3 green, 15 blue, 14 red
Game 5: 6 red, 1 blue, 3 green; 2 blue, 1 red, 2 green"""

def parse(line):
    data={}
    data['game']=int(line[5:line.index(':')])
    data['hands']=[]
    for str in line[line.index(':')+1:].split(';'):
        h={'red':0,'green':0,'blue':0}
        for str2 in str.split(','):
            tmp=str2.strip(' ').split(' ')
            h[tmp[1]]=int(tmp[0])
        data['hands'].append(h)

    data['max_red']=max([x['red'] for x in data['hands']])
    data['max_green']=max([x['green'] for x in data['hands']])
    data['max_blue']=max([x['blue'] for x in data['hands']])
    data['power']=data['max_red']*data['max_green']*data['max_blue']
    data['possible'] = True
    if data['max_red'] > 12:
        data['possible'] = False
    if data['max_green'] > 13:
        data['possible'] = False
    if data['max_blue'] > 14:
        data['possible'] = False


    return data
def loadFile(path):
    with open(path,'r') as f:
        return f.read()

if __name__ == '__main__':
    input=loadFile('day2_input')
    res=[]
    total=0
    power_sum=0
    for row in input.split('\n'):
        data=parse(row)
        if data['possible']:
            total=total+data['game']
        power_sum=power_sum+data['power']
    print('total: %s, power: %s ' % (total,power_sum,))

[Language: Lean4]

I’ll only post the actual parsing and solution. I have written some helpers which are in other files, as is the main function. For the full code, please see my github repo.

structure Draw (α : Type) where
  red : α
  green : α
  blue : α
  deriving Repr

structure Game where
  id : Nat
  draw : List $ Draw Nat
  deriving Repr

def parse (input : String) : Option $ List Game :=
  let lines := input.splitTrim (. == '\n')
  let lines := lines.filter (not ∘ String.isEmpty)
  let parse_single_line : (String → Option Game):= λ (l : String) ↦ do
    let parse_id := λ (s : String) ↦ do
      let rest ← if s.startsWith "Game " then some (s.drop 5) else none
      rest.toNat?
    let parse_draw := λ (s : String) ↦ do
      let s := s.splitTrim (· == ',')
      let findAndRemoveTail := λ (s : String) (t : String) ↦
        if s.endsWith t then
          some $ String.dropRight s (t.length)
        else
          none
      let update_draw_parse := λ (pd : Option (Draw (Option String))) (c : String) ↦ do
        let old ← pd
        let red := findAndRemoveTail c " red"
        let green := findAndRemoveTail c " green"
        let blue := findAndRemoveTail c " blue"
        match red, green, blue with
        | some red, none, none => match old.red with
          | none => some $ {old with red := some red}
          | some _ => none
        | none, some green, none => match old.green with
          | none => some $ {old with green := some green}
          | some _ => none
        | none, none, some blue => match old.blue with
          | none => some $ {old with blue := some blue}
          | some _ => none
        | _, _, _  => none
      let parsed_draw ← s.foldl update_draw_parse (some $ Draw.mk none none none)
      let parsed_draw := {
        red := String.toNat? <$> parsed_draw.red,
        green := String.toNat? <$> parsed_draw.green,
        blue := String.toNat? <$> parsed_draw.blue : Draw _}
      let extractOrFail := λ (s : Option $ Option Nat) ↦ match s with
        | none => some 0
        | some none => none
        | some $ some x => some x
      let red ← extractOrFail parsed_draw.red
      let green ← extractOrFail parsed_draw.green
      let blue ← extractOrFail parsed_draw.blue
      pure { red := red, blue := blue, green := green : Draw _}
    let parse_draws := λ s ↦ List.mapM parse_draw $ s.splitTrim (· == ';')
    let (id, draw) ← match l.splitTrim (· == ':') with
    | [l, r] => Option.zip (parse_id l) (parse_draws r)
    | _ => none
    pure { id := id, draw := draw}
  lines.mapM parse_single_line

def part1 (games : List Game) : Nat :=
  let draw_possible := λ g ↦ g.red ≤ 12 && g.green ≤ 13 && g.blue ≤ 14
  let possible := flip List.all draw_possible
  let possible_games := games.filter (possible ∘ Game.draw)
  possible_games.map Game.id |> List.foldl Nat.add 0

def part2 (games : List Game) : Nat :=
  let powerOfGame := λ (g : Game) ↦
    let minReq := λ (c : Draw Nat → Nat) ↦
      g.draw.map c |> List.maximum? |> flip Option.getD 0
    minReq Draw.red * minReq Draw.green * minReq Draw.blue
  let powers := games.map powerOfGame
  powers.foldl Nat.add 0

Haskell

A rather opaque parser, but much shorter than I could manage with Parsec.

import Data.Bifunctor
import Data.List.Split
import Data.Map.Strict (Map)
import qualified Data.Map.Strict as Map
import Data.Tuple

readGame :: String -> (Int, [Map String Int])
readGame = bimap (read . drop 5) (map readPull . splitOn "; " . drop 2) . break (== ':')
  where
    readPull = Map.fromList . map (swap . bimap read tail . break (== ' ')) . splitOn ", "

possibleWith limit = and . Map.intersectionWith (>=) limit

main = do
  games <- map (fmap (Map.unionsWith max) . readGame) . lines <$> readFile "input02"
  let limit = Map.fromList [("red", 12), ("green", 13), ("blue", 14)]
  print $ sum $ map fst $ filter (possibleWith limit . snd) games
  print $ sum $ map (product . snd) games

Late as always, as I’m on UK time and can’t work on these until late evening.

Part 01 and Part 02 in Rust 🦀 :

use std::{
    env, fs,
    io::{self, BufRead, BufReader},
};

#[derive(Debug)]
struct Sample {
    r: u32,
    g: u32,
    b: u32,
}

fn split_cube_set(set: &[&str], colour: &str) -> Option {
    match set.iter().find(|x| x.ends_with(colour)) {
        Some(item) => item
            .trim()
            .split(' ')
            .next()
            .expect("Found item is present")
            .parse::()
            .ok(),
        None => None,
    }
}

fn main() -> io::Result<()> {
    let args: Vec = env::args().collect();
    let filename = &args[1];
    let file = fs::File::open(filename)?;
    let reader = BufReader::new(file);
    let mut valid_game_ids_sum = 0;
    let mut game_power_sum = 0;
    let max_r = 12;
    let max_g = 13;
    let max_b = 14;
    for line_result in reader.lines() {
        let mut valid_game = true;
        let line = line_result.unwrap();
        let line_split: Vec<_> = line.split(':').collect();
        let game_id = line_split[0]
            .split(' ')
            .collect::>()
            .last()
            .expect("item exists")
            .parse::()
            .expect("is a number");
        let rest = line_split[1];
        let cube_sets = rest.split(';');
        let samples: Vec = cube_sets
            .map(|set| {
                let set_split: Vec<_> = set.split(',').collect();
                let r = split_cube_set(&set_split, "red").unwrap_or(0);
                let g = split_cube_set(&set_split, "green").unwrap_or(0);
                let b = split_cube_set(&set_split, "blue").unwrap_or(0);
                Sample { r, g, b }
            })
            .collect();
        let mut highest_r = 0;
        let mut highest_g = 0;
        let mut highest_b = 0;
        for sample in &samples {
            if !(sample.r <= max_r && sample.g <= max_g && sample.b <= max_b) {
                valid_game = false;
            }
            highest_r = u32::max(highest_r, sample.r);
            highest_g = u32::max(highest_g, sample.g);
            highest_b = u32::max(highest_b, sample.b);
        }
        if valid_game {
            valid_game_ids_sum += game_id;
        }
        game_power_sum += highest_r * highest_g * highest_b;
    }
    println!("Sum of game ids: {valid_game_ids_sum}");
    println!("Sum of game powers: {game_power_sum}");
    Ok(())
}

A solution in Nim language. Pretty straightforward code. Most logic is just parsing input + a bit of functional utils: allIt checks if all items in a list within limits to check if game is possible and mapIt collects red, green, blue cubes from each set of game.

https://codeberg.org/Archargelod/aoc23-nim/src/branch/master/day_02/solution.nim

import std/[strutils, strformat, sequtils]

type AOCSolution[T] = tuple[part1: T, part2: T]

type
  GameSet = object
    red, green, blue: int
  Game = object
    id: int
    sets: seq[GameSet]

const MaxSet = GameSet(red: 12, green: 13, blue: 14)

func parseGame(input: string): Game =
  result.id = input.split({':', ' '})[1].parseInt()
  let sets = input.split(": ")[1].split("; ").mapIt(it.split(", "))
  for gSet in sets:
    var gs = GameSet()
    for pair in gSet:
      let
        pair = pair.split()
        cCount = pair[0].parseInt
        cName = pair[1]

      case cName:
      of "red":
        gs.red = cCount
      of "green":
        gs.green = cCount
      of "blue":
        gs.blue = cCount

    result.sets.add gs

func isPossible(g: Game): bool =
  g.sets.allIt(
    it.red <= MaxSet.red and
    it.green <= MaxSet.green and
    it.blue <= MaxSet.blue
  )


func solve(lines: seq[string]): AOCSolution[int]=
  for line in lines:
    let game = line.parseGame()

    block p1:
      if game.isPossible():
        result.part1 += game.id

    block p2:
      let
        minRed = game.sets.mapIt(it.red).max()
        minGreen = game.sets.mapIt(it.green).max()
        minBlue = game.sets.mapIt(it.blue).max()

      result.part2 += minRed * minGreen * minBlue


when isMainModule:
  let input = readFile("./input.txt").strip()
  let (part1, part2) = solve(input.splitLines())

  echo &"Part 1: The sum of valid game IDs equals {part1}."
  echo &"Part 2: The sum of the sets' powers equals {part2}."

Python, interesting that the readMax function that I created on part 1 was also what I needed for part 2. https://github.com/massahud/advent-of-code-2023/blob/main/day02/day02.ipynb

[LANGUAGE: C#]

Part 1:

var list = new List((await File.ReadAllLinesAsync(@".\Day 2\PuzzleInput.txt")));
int conter = 0;
foreach (var line in list)
{
    string[] split = line.Split(":");
    int game = Int32.Parse( split[0].Split(" ")[1]);
    string[] bagContents = split[1].Split(";");
    var max = new Dictionary() { { "red", 0 }, { "green", 0 }, { "blue", 0 } };
    foreach (var content in bagContents)
    {
        string pattern = @"(\d+) (\w+)";
        MatchCollection matches = Regex.Matches(content, pattern);

        foreach (Match match in matches)
        {
            int number = Int32.Parse(match.Groups[1].Value);
            string color = match.Groups[2].Value;
            max[color] = (max[color] >= number)? max[color] : number;
        }
    }
    conter += (max["red"] <= 12 && max["green"] <= 13 && max["blue"] <= 14) ? game : 0;

}
Console.WriteLine(conter);

Part 2:

var list = new List((await File.ReadAllLinesAsync(@".\Day 2\PuzzleInput.txt")));

int conter = 0;
foreach (var line in list)
{
    string[] split = line.Split(":");
    int game = Int32.Parse(split[0].Split(" ")[1]);
    string[] bagContents = split[1].Split(";");
        var max = new Dictionary();
    foreach (var content in bagContents)
    {
        string pattern = @"(\d+) (\w+)";

        MatchCollection matches = Regex.Matches(content, pattern);

        foreach (Match match in matches)
        {
            int number = Int32.Parse(match.Groups[1].Value);
            string color = match.Groups[2].Value;
            if (!max.ContainsKey(color))
                max[color] = number;
            else if(max[color] < number)
                max[color] = number;
        }
    }
    conter += max.Values.Aggregate(1, (total, value) => total *  value );

}
Console.WriteLine(conter);

Factor on github:

note: lemmy mangles the less-than-or-equals sign in the possible? function

USING: arrays assocs io.encodings.utf8 io.files kernel math
math.parser math.vectors prettyprint regexp sequences splitting
;
IN: aoc-2023.day02

: known-color ( color-phrases regexp -- n )
  all-matching-subseqs [ 0 ] [
    [ split-words first string>number ] map supremum
  ] if-empty
;

: line>known-rgb ( str -- game-id known-rgb )
  ": " split1 [ split-words last string>number ] dip
  R/ \d+ red/ R/ \d+ green/ R/ \d+ blue/
  [ known-color ] tri-curry@ tri 3array
;

: possible? ( known-rgb test-rgb -- ? )
  v<= [ ] all?
;

: part1 ( -- )
  "input.txt" utf8 file-lines
  [ line>known-rgb 2array ] map
  [ last { 12 13 14 } possible? ] filter
  [ first ] map-sum .
;

: part2 ( -- )
  "input.txt" utf8 file-lines
  [ line>known-rgb nip product ] map-sum .
;

Found a C per-char solution, that is, no lines, splitting, lookahead, etc. It wasn’t even necessary to keep match lengths for the color names because they all have unique characters, e.g. ‘b’ only occurs in “blue” so then you can attribute the count to that color.

int main()
{
	int p1=0,p2=0, id=1,num=0, r=0,g=0,b=0, c;

	while ((c = getchar()) != EOF)
		if (c==',' || c==';' || c==':') num = 0; else
		if (c>='0' && c<='9') num = num*10 + c-'0'; else
		if (c=='d') r = MAX(r, num); else
		if (c=='g') g = MAX(g, num); else
		if (c=='b') b = MAX(b, num); else
		if (c=='\n') {
			p1 += (r<=12 && g<=13 && b<=14) * id;
			p2 += r*g*b;
			r=g=b=0; id++;
		}

	printf("%d %d\n", p1, p2);
	return 0;
}

Golfed:

c,p,P,i,n,r,g,b;main(){while(~
(c=getchar()))c==44|c==58|59==
c?n=0:c>47&c<58?n=n*10+c-48:98
==c?b=b>n?b:n:c=='d'?r=r>n?r:n
:c=='g'?g=g>n?g:n:10==c?p+=++i
*(r<13&g<14&b<15),P+=r*g*b,r=g
=b=0:0;printf("%d %d\n",p,P);}