Advent of Code 2023 - Day 4

main.go

package main

import (
	"fmt"
	"math"
	"os"
	"regexp"
	"slices"
	"strings"
)

func LoadLinesFromFile(src string) []string {
	data, err := os.ReadFile("input.txt")
	if err != nil {
		panic(err)
	}
	return strings.Split(string(data), "\r\n")
}

func GetScratchNumbers(line string) ([]string, []string) {
	re := regexp.MustCompile(`\d+`)
	data := strings.Split(strings.Split(line, ":")[1], "|")
	return re.FindAllString(data[0], -1), re.FindAllString(data[1], -1)
}

func PartOne(lines []string) int {
	points := 0
	for _, line := range lines {
		winners, ticket := GetScratchNumbers(line)
		wins := -1
		for _, number := range ticket {
			if slices.Contains(winners, number) {
				wins++
			}
		}
		points += int(math.Pow(2, float64(wins)))
	}
	return points
}

func PartTwo(lines []string) int {
	copies := make([]int, len(lines))
	total := 0
	for i, line := range lines {
		copies[i]++
		winners, ticket := GetScratchNumbers(line)
		wins := 0
		for _, number := range ticket {
			if slices.Contains(winners, number) {
				wins++
				copies[i+wins] += copies[i]
			}
		}
		total += copies[i]
	}
	return total
}

func main() {
	lines := LoadLinesFromFile("input.txt")
	fmt.Println("PartOne:", PartOne(lines))
	fmt.Println("PartTwo:", PartTwo(lines))
}