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package part_01
import (
"os"
"slices"
"strconv"
"strings"
)
const USE_SAMPLE = false
type UnparsedCard struct {
id string
winningNumbers []string
haveNumbers []string
}
type Card struct {
id int
winningNumbers []int
haveNumbers []int
}
func (c UnparsedCard) parse() Card {
var card Card
id, err := strconv.Atoi(c.id)
if err != nil {
panic(err)
}
card.id = id
for _, number := range c.winningNumbers {
num, err := strconv.Atoi(number)
if err != nil {
panic(err)
}
card.winningNumbers = append(card.winningNumbers, num)
}
for _, number := range c.haveNumbers {
num, err := strconv.Atoi(number)
if err != nil {
panic(err)
}
card.haveNumbers = append(card.haveNumbers, num)
}
return card
}
func Solve() {
var contents []byte
if USE_SAMPLE {
contents, _ = os.ReadFile("../_input/day_04_part_01_sample.txt")
} else {
contents, _ = os.ReadFile("../_input/day_04.txt")
}
lines := strings.Split(string(contents), "\n")
answer := 0
for _, line := range lines {
if line == "" || line == "\n" {
continue
}
card := parseCardLine(line)
score := tallyScore(card)
answer += score
}
println(answer)
}
// "Card 1: 41 48 83 86 17 | 83 86 6 31 17 9 48 53"
func parseCardLine(line string) Card {
var unparsedCard UnparsedCard
filteredLine := strings.ReplaceAll(line, "\r", "")
// "Card 1"
card_parts := strings.Split(filteredLine, ":")[0]
id_parts := strings.Split(card_parts, " ")
id := id_parts[len(id_parts)-1]
unparsedCard.id = strings.ReplaceAll(id, " ", "")
// "41 48 83 86 17 | 83 86 6 31 17 9 48 53"
numbers := strings.Split(filteredLine, ":")[1]
// " 41 48 83 86 17"
winningNumberString := strings.Split(numbers, "|")[0]
// ["", "41", "48", "83", "86", "17"]
winningNumbers := strings.Split(winningNumberString, " ")
for _, num := range winningNumbers {
if num == "" || num == " " {
continue
}
unparsedCard.winningNumbers = append(unparsedCard.winningNumbers, num)
}
// " 83 86 6 31 17 9 48 53"
haveNumberString := strings.Split(numbers, "|")[1]
// ["", "83", "86", "", "6", "31", "17", "", "9", "48", "53"]
haveNumbers := strings.Split(haveNumberString, " ")
for _, num := range haveNumbers {
if num == "" || num == " " {
continue
}
unparsedCard.haveNumbers = append(unparsedCard.haveNumbers, num)
}
return unparsedCard.parse()
}
func tallyScore(card Card) int {
score := 0
for _, winningNumber := range card.winningNumbers {
if slices.Contains(card.haveNumbers, winningNumber) {
if score == 0 {
score = 1
} else {
score *= 2
}
}
}
return score
}
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