Day 3: Mull It Over

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FAQ

  • gothink@lemmy.caEnglish
    0·
    12 days ago

    I also used Go - my solution for part 1 was essentially identical to yours. I went a different route for part 2 that I think ended up being simpler though.

    I just prepended do() and don't() to the original regex with a |, that way it captured all 3 in order and I just looped through all the matches once and toggled the isEnabled flag accordingly.

    Always interesting to see how other people tackle the same problem!

    Part 2 Code 
    func part2() {
	filePath := "input.txt"
	file, _ := os.Open(filePath)
	defer file.Close()

	pattern := regexp.MustCompile(`do\(\)|don't\(\)|mul\((\d{1,3}),(\d{1,3})\)`)
	productSum := 0
	isEnabled := true

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		matches := pattern.FindAllStringSubmatch(line, -1)

		for _, match := range matches {
			if match[0] == "do()" {
				isEnabled = true
			} else if match[0] == "don't()" {
				isEnabled = false
			} else if isEnabled && len(match) == 3 {
				n, _ := strconv.Atoi(match[1])
				m, _ := strconv.Atoi(match[2])
				productSum += n * m
			}
		}
	}

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