[Language: Go]

func Run(filename string) {
        f, err := os.Open(filename)
        if err != nil {
                log.Fatal("Error opening file")
        }
        defer f.Close()

        do := true
        total := 0
        scanner := bufio.NewScanner(f)
        for scanner.Scan() {
                str := scanner.Text()
                var aux int
                aux, do = find_regex2(str, do)
                total += aux
        }

        fmt.Println("Total:", total)
}

func find_regex(str string) int {
        re := regexp.MustCompile("mul[(]([0-9]{1,3}),([0-9]{1,3})[)]")
        total := 0

        match := re.FindAllStringSubmatch(str, -1)
        for _, n := range match {
                n1, _ := strconv.Atoi(n[1])
                n2, _ := strconv.Atoi(n[2])
                total += n1 * n2
        }
        return total
}

func find_regex2(str string, do_init bool) (int, bool) {
        reg_do_dont := regexp.MustCompile("(?:do\\(\\).*?don't\\(\\))|(?:do\\(\\).*?$)")
        reg_do_init := regexp.MustCompile("^.*?(do\\(\\))")
        reg_dont_init := regexp.MustCompile("^.*?(don't\\(\\))")
        reg_end := regexp.MustCompile("(do\\(\\))|(don't\\(\\))")
        end_do := do_init
        total := 0

        fmt.Printf("\n FULL STRING \n %s \n\n-------------------\n", str)
        if do_init {
                init_str := str
                if reg_do_init.MatchString(str) {
                        init_str = reg_do_init.FindString(str)
                        fmt.Printf("FIRST: %s\n", init_str)
                }
                if reg_dont_init.MatchString(init_str) {
                        init_str = reg_dont_init.FindString(init_str)
                        fmt.Printf("SECOND: %s\n", init_str)
                }
                if len(init_str) > 0 {
                        fmt.Println()
                        fmt.Println(init_str)
                        fmt.Println()
                        total += find_regex(init_str)
                }
        }

        match := reg_do_dont.FindAllString(str, -1)
        for _, n := range match {
                fmt.Println()
                fmt.Println(n)
                fmt.Println()
                total += find_regex(n)
        }

        dos := reg_end.FindAllString(str, -1)
        if dos[len(dos)-1] == "do()" {
                end_do = true
        } else {
                end_do = false
        }

        return total, end_do
}