From e0b4f292c2d8f55b01fcd80764c3871646753048 Mon Sep 17 00:00:00 2001
From: Alan R Evans <alan@kageds.com>
Date: Tue, 3 Dec 2024 07:19:28 +0000
Subject: [PATCH] day3

---
 2024/go/day01/day01.go      |  2 +-
 2024/go/day03/day03.go      | 64 +++++++++++++++++++++++++++++++++++++
 2024/go/day03/day03_test.go | 17 ++++++++++
 2024/go/main.go             |  6 +++-
 4 files changed, 87 insertions(+), 2 deletions(-)
 create mode 100644 2024/go/day03/day03.go
 create mode 100644 2024/go/day03/day03_test.go

diff --git a/2024/go/day01/day01.go b/2024/go/day01/day01.go
index 8d706d0..233392c 100644
--- a/2024/go/day01/day01.go
+++ b/2024/go/day01/day01.go
@@ -35,7 +35,7 @@ func Part2(input string) int {
 	list2 := make(map[int]int)
 
 
-	num := 0
+	num := 1
 	lines := strings.Split(input, "\n")
 	for _, line := range lines {
 		fields := strings.Fields(line)
diff --git a/2024/go/day03/day03.go b/2024/go/day03/day03.go
new file mode 100644
index 0000000..a92e610
--- /dev/null
+++ b/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
+}
diff --git a/2024/go/day03/day03_test.go b/2024/go/day03/day03_test.go
new file mode 100644
index 0000000..f0ecf4a
--- /dev/null
+++ b/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)
+}
diff --git a/2024/go/main.go b/2024/go/main.go
index 96a06c6..3c8c20d 100644
--- a/2024/go/main.go
+++ b/2024/go/main.go
@@ -9,6 +9,7 @@ import (
 	"adventofcode2024/utils"
 	"adventofcode2024/day01"
 	"adventofcode2024/day02"
+	"adventofcode2024/day03"
 )
 // Usage: go run main.go <NN>
 // assumes input is in day<NN>/input.txt
@@ -23,6 +24,9 @@ func main() {
 	case 2:
 		fmt.Printf("part 1: %d\n", day02.Part1(utils.Readfile(d)))
 		fmt.Printf("part 2: %d\n", day02.Part2(utils.Readfile(d)))
+	case 3:
+		fmt.Printf("part 1: %d\n", day03.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day03.Part2(utils.Readfile(d)))
 	default:
 		panic(fmt.Errorf("no such day: %d", d))
 	}
@@ -30,7 +34,7 @@ func main() {
 
 // Reads day from os.Args.
 func day() int {
-	latest := 1
+	latest := 2
 	if len(os.Args) == 1 {
 		return latest
 	}