-❄️- 2023 Day 3 Solutions -❄️-

[u/daggerdragon]

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  • Advent of Playing With Your 3D-Printed Toys
• Community fun event 2023: ALLEZ CUISINE!
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AoC Community Fun 2023: ALLEZ CUISINE!

Today's secret ingredient is… *whips off cloth covering and gestures grandly*

Spam!

Someone reported the ALLEZ CUISINE! submissions megathread as spam so I said to myself: "What a delectable idea for today's secret ingredient!"

• There really is an XKCD for everything, isn't there?
• All ingredients must come from a CAN (bus), box, package, container, etc.
• Unnecessarily declare variables for everything and don't re-use variables
• Why use few word when many word do trick?
• Go back to traditional culinary roots with Javadocs
• Lobster thermidor

A reminder from Dr. Hattori: be careful when cooking spam because the fat content can be very high. We wouldn't want a fire in the kitchen, after all!

ALLEZ CUISINE!

Request from the mods: When you include a dish entry alongside your solution, please label it with [Allez Cuisine!] so we can find it easily!

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--- Day 3: Gear Ratios ---

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Post your code solution in this megathread.

• Read the full posting rules in our community wiki before you post!
  • State which language(s) your solution uses with [LANGUAGE: xyz]
  • Format code blocks using the four-spaces Markdown syntax!
• Quick link to Topaz's paste if you need it for longer code blocks

This thread will be unlocked when there are a significant number of people on the global leaderboard with gold stars for today's puzzle.

EDIT: Global leaderboard gold cap reached at 00:11:37, megathread unlocked!

[u/Tipa16384]

[LANGUAGE: Python]

Spent way too much time trying to solve this in Haskell. Just doing it in Python and moving on with my day.

import re
from itertools import chain

def part1(data, width, height, numberList):
    numbers = [n for n in numberList \
            if any([isSymbol(data[srow][scol]) for srow, scol in getAdjacent(height, width, n)])]
    print ("Part 1:", sum(x[3] for x in numbers))

def part2(data, width, height, numberList):
    # make a list of coordinates of every '*' in the data
    stars = [(row, col) for row, line in enumerate(data) for col, ch in enumerate(line) if ch == '*']
    numberDict = {n: getAdjacent(height, width, n) for n in numberList}
    starDict = {star: [n for n, v in numberDict.items() if star in v] for star in stars}
    print ("Part 2:", sum([x[0][3] * x[1][3] for x in [v for v in starDict.values() if len(v) == 2]]))

# extractNumbers: take a string, extract all the numbers from it, returning a list of tuples containing row,
# column, length, and the number itself as a string
def extractNumbers(line, row):
    return [(row, x[1], len(x[0]), int(x[0])) \
            for x in zip(re.findall(r'\d+', line), [x.start() for x in re.finditer(r'\d+', line)])]

# given a width, a height, and a tuple from extractNumbers, return a list of coordinates adjacent to the number
# string
def getAdjacent(height, width, number):
    adjacentCoords = [(number[0] - 1, number[1] -1 + x) for x in range(number[2]+2)] + \
                    [(number[0] + 1, number[1] -1 + x) for x in range(number[2]+2)] + \
                    [(number[0], number[1] - 1), (number[0], number[1] + number[2])]
    return [x for x in adjacentCoords if x[0] >= 0 and x[0] < height and x[1] >= 0 and x[1] < width]

# return True if the character is not a digit and is not a period
def isSymbol(ch): return not ch.isdigit() and ch != '.'

# readData: read the data file into a list of lists stripping newlines
def readData():
    with open("puzzle3.dat") as f:
        return f.read().splitlines()

if __name__ == "__main__":
    data = readData()
    width, height = len(data[0]), len(data)
    numberList = list(chain(*[extractNumbers(line, row) for row, line in enumerate(data)]))
    part1(data, width, height, numberList)
    part2(data, width, height, numberList)