Add day3 part2 solution

day-3/part2/part2.go

@@ -0,0 +1,60 @@
+package part2
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strconv"
+)
+
+func check(e error) {
+	if e != nil {
+		panic(e)
+	}
+}
+
+func getFileData() (*os.File, *bufio.Scanner) {
+	wd, err := os.Getwd()
+	check(err)
+
+	inputPath := filepath.Join(wd, "input.txt")
+
+	file, err := os.Open(inputPath)
+	check(err)
+
+	return file, bufio.NewScanner(file)
+}
+
+func Run() {
+
+	file, scanner := getFileData()
+	defer file.Close()
+
+	ans := 0
+	enabled := true
+	re := regexp.MustCompile(`mul\((\d+),(\d+)\)|(do\(\))|don't\(\)`)
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		matches := re.FindAllStringSubmatch(line, -1)
+
+		for _, match := range matches {
+			if match[1] != "" && match[2] != "" {
+				x, _ := strconv.Atoi(match[1])
+				y, _ := strconv.Atoi(match[2])
+				if enabled {
+					ans += (x * y)
+				}
+			} else if match[0] == "do()" {
+				enabled = true
+			} else if match[0] == "don't()" {
+				enabled = false
+			}
+		}
+
+	}
+
+	fmt.Println(ans)
+}

day-3/test2.txt

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))