day3

2024/go/day03/day03.go

@@ -0,0 +1,64 @@
+package day03
+
+import (
+	"adventofcode2024/utils"
+	"fmt"
+	"regexp"
+)
+
+func Part1(input string) int {
+	val := 0
+
+	pattern := `mul\((\d{1,3}),(\d{1,3})\)`
+	re := regexp.MustCompile(pattern)
+	matches := re.FindAllStringSubmatch(input, -1)
+
+	fmt.Println("Matches found:")
+	for _, match := range matches {
+		if len(match) == 3 { // match[1] is x, match[2] is y
+			x := utils.MustAtoi(match[1])
+			y := utils.MustAtoi(match[2])
+			val += x * y
+		}
+	}
+	return val
+}
+
+func Part2(input string) int {
+	val := 0
+	pattern := `mul\((\d{1,3}),(\d{1,3})\)`
+	re := regexp.MustCompile(pattern)
+	matches := re.FindAllStringSubmatchIndex(input, -1)
+
+	fmt.Println("Matches found:")
+	for _, match := range matches {
+		if len(match) == 6 { 
+			xStart, xEnd := match[2], match[3]
+			yStart, yEnd := match[4], match[5]
+			x := utils.MustAtoi(input[xStart:xEnd])
+			y := utils.MustAtoi(input[yStart:yEnd])
+			if do(input[:xStart]) {
+				val += x * y
+			}
+		}
+	}
+	return val
+}
+
+func do(input string) bool {
+	pattern := `don't\(\)|do\(\)`
+	re := regexp.MustCompile(pattern)
+
+	matches := re.FindAllString(input, -1)
+
+	if len(matches) > 0 {
+		// Get the last match
+		lastMatch := matches[len(matches)-1]
+		if lastMatch == "don't()" {
+			return false
+		} else if lastMatch == "do()" {
+			return true
+		}
+	}
+	return true
+}

2024/go/day03/day03_test.go

@@ -0,0 +1,17 @@
+package day03
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1("")
+	require.Equal(t, 0, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2("xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))")
+	require.Equal(t, 48, r)
+}