Advent of Code 2023 - Day 4 - Salesforce Apex

--- Day 4: Scratchcards ---

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

Advent Calendar Progress

Day 04 - Solution

	public with sharing class day04 {
	public static Integer part2(List<String> puzzleInputLines) {
	Map<Integer,Integer> cardNumberToCopies = new Map<Integer,Integer>();
	Map<Integer,Integer> cardNumberToWinners = new Map<Integer,Integer>();
	// iterate each card
	for(Integer i = 0; i < puzzleInputLines.size(); i++) {
	String card = puzzleInputLines[i];
	Integer cardNumber = Integer.valueOf(card.substring(card.indexOf(' ') + 1, card.indexOf(':')).trim());
	Integer totalCardWinners = processTotalCardWinners(puzzleInputLines[i]);
	cardNumberToCopies.put(cardNumber, 1);
	cardNumberToWinners.put(cardNumber, totalCardWinners);
	}
	for(Integer i = 0; i < puzzleInputLines.size(); i++) {
	String card = puzzleInputLines[i];
	Integer cardNumber = Integer.valueOf(card.substring(card.indexOf(' ') + 1, card.indexOf(':')).trim());
	for(Integer y = 1; y <= cardNumberToWinners.get(cardNumber); y++) {
	Integer nextCardNumber = cardNumber + y;
	// Your copy of card 2 also wins one copy each of cards 3 and 4.
	Integer currentCopies = cardNumberToCopies.get(nextCardNumber) + 1;
	cardNumberToCopies.put(nextCardNumber, currentCopies);
	}
	}
	Integer totalCards = 0;
	for(Integer copy : cardNumberToCopies.values()) {
	totalCards += copy;
	}
	return totalCards;
	}
	public static Integer part1(List<String> puzzleInputLines) {
	Integer cardPoints = 0;
	// iterate each card
	for(Integer i = 0; i < puzzleInputLines.size(); i++) {
	Integer totalCardWinners = processTotalCardWinners(puzzleInputLines[i]);
	cardPoints += calculatePoints(totalCardWinners);
	}
	return cardPoints;
	}
	public static Integer processTotalCardWinners(String card) {
	String winningNumbers = card.substring(card.indexOf(':') + 1, card.indexOf('|'));
	String myNumbers = card.substring(card.indexOf('|') + 1, card.length());
	List<Integer> resultWinning = new List<Integer>(convertToListOfIntegers(winningNumbers));
	List<Integer> resultMyNumbers = convertToListOfIntegers(myNumbers);
	// card map
	Map<Set<Integer>,List<Integer>> cardMap = new Map<Set<Integer>,List<Integer>>();
	cardMap.put(
	new Set<Integer>(convertToListOfIntegers(winningNumbers)),
	convertToListOfIntegers(myNumbers)
	);
	return calculateCardWinners(cardMap);
	}
	public static Integer calculateCardWinners(Map<Set<Integer>,List<Integer>> cardMap) {
	Integer cardTotalWinners = 0;
	for(Set<Integer> winners : cardMap.keySet()) {
	for(Integer myNumber : cardMap.get(winners)) {
	if(winners.contains(myNumber)) {
	cardTotalWinners++;
	}
	}
	}
	return cardTotalWinners;
	}
	public static Integer calculatePoints(Integer cardTotalWinners) {
	if(cardTotalWinners < 1) {
	return 0;
	}
	// first winner is 1 point
	Integer points = 1;
	// double the score for each point after 1
	for(Integer i = 2; i <= cardTotalWinners; i++) {
	points *= 2;
	}
	return points;
	}
	public static List<Integer> convertToListOfIntegers(String inputString) {
	List<Integer> integerList = new List<Integer>();
	// Split the string into an array of substrings
	List<String> stringArray = inputString.trim().split(' ');
	// Convert each substring to an integer and add to the list
	for(String str : stringArray) {
	if(String.isNotBlank(str)) {
	integerList.add(Integer.valueOf(str.trim()));
	}
	}
	return integerList;
	}
	}

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