Day 3 done

internal/day03/handler.go

@@ -0,0 +1,53 @@
+package day03
+
+import (
+	"regexp"
+	"strings"
+
+	"aoc2024/internal/common"
+)
+
+func Handle(input []byte) (int, int) {
+	result1 := getSumMulStr(input)
+	result2 := 0
+	dos := getDo(input)
+	for _, do := range dos {
+		result2 += getSumMulStr(do)
+	}
+
+	return result1, result2
+}
+
+func getSumMulStr(input []byte) int {
+	sum := 0
+	re := regexp.MustCompile(`(mul\(\d+,\d+\))`)
+	reNumber := regexp.MustCompile(`(\d+)`)
+
+	matches := re.FindAll(input, -1)
+	for _, match := range matches {
+		numberStr := reNumber.FindAll(match, -1)
+		sum += common.StrToInt(string(numberStr[0])) * common.StrToInt(string(numberStr[1]))
+
+	}
+
+	return sum
+}
+
+func getDo(input []byte) [][]byte {
+	re := regexp.MustCompile(`(do\(\)|don't\(\))`)
+	firstIndex := re.FindIndex(input)
+	firstSegment := input[:firstIndex[1]]
+	re = regexp.MustCompile(`do\(\)`)
+	indexes := re.FindAllIndex(input, -1)
+	lastSegment := input[indexes[len(indexes)-1][0]:]
+
+	re = regexp.MustCompile(`(?s)(do\(\)).*?(don't\(\))`)
+	matches := re.FindAll(input, -1)
+
+	matches = append(matches, firstSegment)
+	if !strings.Contains(string(lastSegment), "don't()") {
+		matches = append(matches, lastSegment)
+	}
+
+	return matches
+}