Started AOC 2020 - solved the first 4.5 days.

2020/day02.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+
+	"git.annabunch.es/annabunches/adventofcode/2020/lib/fileutils"
+)
+
+func checkLine(line string, step string) int {
+	if line == "" {
+		return 0
+	}
+
+	data := strings.Split(line, " ")
+	minMaxData := strings.Split(data[0], "-")
+
+	min, err := strconv.Atoi(minMaxData[0])
+	if err != nil {
+		log.Panicf(err.Error())
+	}
+	max, err := strconv.Atoi(minMaxData[1])
+	if err != nil {
+		log.Panicf(err.Error())
+	}
+	char := strings.TrimSuffix(data[1], ":")
+
+	switch step {
+	case "1":
+		count := strings.Count(data[2], char)
+
+		if count >= min && count <= max {
+			return 1
+		}
+		return 0
+	case "2":
+		bchar := char[0]
+		if (data[2][min-1] == bchar || data[2][max-1] == bchar) &&
+			!(data[2][min-1] == bchar && data[2][max-1] == bchar) {
+			return 1
+		}
+		return 0
+	}
+
+	return 0
+}
+
+func main() {
+	step := os.Args[1]
+	values := fileutils.InputParserStrings(os.Args[2])
+
+	total := 0
+	for _, line := range values {
+		total += checkLine(line, step)
+	}
+	fmt.Println("Valid passwords:", total)
+}