Fourth day

internal/04/04.go

@@ -0,0 +1,57 @@
+package day04
+
+import (
+	"math"
+	"regexp"
+	"strconv"
+	"strings"
+
+	utils "git.anthonygueguen.fr/g3po/aoc2023/internal"
+)
+
+func GetResult(content []string) []int {
+	points := 0
+	nbr_card := 0
+	re := regexp.MustCompile(`\d+`)
+	distribution := make(map[int]int)
+	distribution[1] = 1
+
+	for i, line := range content {
+		current_card := i + 1
+		if _, ok := distribution[current_card]; !ok {
+			distribution[current_card] = 1
+		}
+		line = strings.Split(line, ":")[1]
+		split := strings.Split(line, "|")
+		set1, set2 := split[0], split[1]
+		winning_num := make(map[int]struct{})
+		num_count := 0
+		for _, n := range re.FindAllString(set1, -1) {
+			num := utils.Must(strconv.Atoi(n))
+			winning_num[num] = struct{}{}
+		}
+		for _, n := range re.FindAllString(set2, -1) {
+			num := utils.Must(strconv.Atoi(n))
+			if _, ok := winning_num[num]; ok {
+				num_count++
+			}
+		}
+		if num_count > 0 {
+			points += int(math.Pow(2.0, float64(num_count-1)))
+			for followin_card := 1; followin_card <= num_count; followin_card++ {
+				distribution_following_card := 1
+				if val, ok := distribution[current_card+followin_card]; ok {
+					distribution_following_card = val
+				}
+				distribution[current_card+followin_card] = distribution_following_card + distribution[current_card]
+			}
+		}
+	}
+	for i := 1; i <= len(content); i++ {
+		if _, ok := distribution[i]; !ok {
+			break
+		}
+		nbr_card += distribution[i]
+	}
+	return []int{points, nbr_card}
+}