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This file is part of Logtalk <https://logtalk.org/>  
SPDX-FileCopyrightText: 1998-2023 Paulo Moura <pmoura@logtalk.org>  
SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

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To load this example and for sample queries, please see the `SCRIPT.txt`
file.

This folder contains a Logtalk solution for the Advent of Code 2023 Day 4
problem:

https://adventofcode.com/2023/day/4

Copy of the problem description:

> --- Day 4: Scratchcards ---
> 
> --- Part One ---
> 
> The gondola takes you up. Strangely, though, the ground doesn't seem to
> be coming with you; you're not climbing a mountain. As the circle of Snow
> Island recedes below you, an entire new landmass suddenly appears above
> you! The gondola carries you to the surface of the new island and lurches
> into the station.
> 
> As you exit the gondola, the first thing you notice is that the air here
> is much warmer than it was on Snow Island. It's also quite humid. Is this
> where the water source is?
> 
> The next thing you notice is an Elf sitting on the floor across the
> station in what seems to be a pile of colorful square cards.
> 
> "Oh! Hello!" The Elf excitedly runs over to you. "How may I be of service?"
> You ask about water sources.
> 
> "I'm not sure; I just operate the gondola lift. That does sound like
> something we'd have, though - this is Island Island, after all! I bet
> the gardener would know. He's on a different island, though - er, the
> small kind surrounded by water, not the floating kind. We really need
> to come up with a better naming scheme. Tell you what: if you can help
> me with something quick, I'll let you borrow my boat and you can go
> visit the gardener. I got all these scratchcards as a gift, but I
> can't figure out what I've won."
> 
> The Elf leads you over to the pile of colorful cards. There, you discover
> dozens of scratchcards, all with their opaque covering already scratched
> off. Picking one up, it looks like each card has two lists of numbers
> separated by a vertical bar (|): a list of winning numbers and then a
> list of numbers you have. You organize the information into a table
> (your puzzle input).
> 
> As far as the Elf has been able to figure out, you have to figure out
> which of the numbers you have appear in the list of winning numbers.
> The first match makes the card worth one point and each match after
> the first doubles the point value of that card.
> 
> For example:
> 
> Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
> Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
> Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
> Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
> Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
> Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11
> 
> In the above example, card 1 has five winning numbers (41, 48, 83, 86,
> and 17) and eight numbers you have (83, 86, 6, 31, 17, 9, 48, and 53).
> Of the numbers you have, four of them (48, 83, 17, and 86) are winning
> numbers! That means card 1 is worth 8 points (1 for the first match,
> then doubled three times for each of the three matches after the first).
> 
> Card 2 has two winning numbers (32 and 61), so it is worth 2 points.
> Card 3 has two winning numbers (1 and 21), so it is worth 2 points.
> Card 4 has one winning number (84), so it is worth 1 point.
> Card 5 has no winning numbers, so it is worth no points.
> Card 6 has no winning numbers, so it is worth no points.
> So, in this example, the Elf's pile of scratchcards is worth 13 points.
> 
> Take a seat in the large pile of colorful cards. How many points are
> they worth in total?
> 
> --- Part Two ---
> 
> Just as you're about to report your findings to the Elf, one of you realizes
> that the rules have actually been printed on the back of every card this
> whole time.
> 
> There's no such thing as "points". Instead, scratchcards only cause you to
> win more scratchcards equal to the number of winning numbers you have.
> 
> Specifically, you win copies of the scratchcards below the winning card
> equal to the number of matches. So, if card 10 were to have 5 matching
> numbers, you would win one copy each of cards 11, 12, 13, 14, and 15.
> 
> Copies of scratchcards are scored like normal scratchcards and have the
> same card number as the card they copied. So, if you win a copy of card
> 10 and it has 5 matching numbers, it would then win a copy of the same
> cards that the original card 10 won: cards 11, 12, 13, 14, and 15. This
> process repeats until none of the copies cause you to win any more cards.
> (Cards will never make you copy a card past the end of the table.)
> 
> This time, the above example goes differently:
> 
> Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
> Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
> Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
> Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
> Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
> Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11
> 
> - Card 1 has four matching numbers, so you win one copy each of the next
> four cards: cards 2, 3, 4, and 5.
> - Your original card 2 has two matching numbers, so you win one copy each
> of cards 3 and 4.
> - Your copy of card 2 also wins one copy each of cards 3 and 4.
> - Your four instances of card 3 (one original and three copies) have two
> matching numbers, so you win four copies each of cards 4 and 5.
> - Your eight instances of card 4 (one original and seven copies) have one
> matching number, so you win eight copies of card 5.
> - Your fourteen instances of card 5 (one original and thirteen copies) have
> no matching numbers and win no more cards.
> - Your one instance of card 6 (one original) has no matching numbers and
> wins no more cards.
> 
> Once all of the originals and copies have been processed, you end up with
> 1 instance of card 1, 2 instances of card 2, 4 instances of card 3, 8
> instances of card 4, 14 instances of card 5, and 1 instance of card 6.
> In total, this example pile of scratchcards causes you to ultimately have
> 30 scratchcards!
> 
> Process all of the original and copied scratchcards until no more
> scratchcards are won. Including the original set of scratchcards,
> how many total scratchcards do you end up with?
