Started AOC 2020 - solved the first 4.5 days.

2020/day05.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+
+	"git.annabunch.es/annabunches/adventofcode/2020/lib/fileutils"
+)
+
+func calculateSeatNumber(input string) int {
+	if input == "" {
+		return 0
+	}
+
+	row, err := strconv.ParseInt(strings.ReplaceAll(strings.ReplaceAll(input[0:7], "F", "0"), "B", "1"), 2, 32)
+	if err != nil {
+		log.Panicf(err.Error())
+	}
+	col, err := strconv.ParseInt(strings.ReplaceAll(strings.ReplaceAll(input[7:10], "L", "0"), "R", "1"), 2, 32)
+	if err != nil {
+		log.Panicf(err.Error())
+	}
+	return int((row * 8) + col)
+}
+
+func main() {
+	step := os.Args[1]
+	values := fileutils.InputParserStrings(os.Args[2])
+
+	switch step {
+	case "1":
+		max := 0
+		for _, line := range values {
+			seatNumber := calculateSeatNumber(line)
+			if seatNumber > max {
+				max = seatNumber
+			}
+		}
+		fmt.Println("Highest Seat Number:", max)
+	case "2":
+		// build a map of all seat numbers then just print the ones between 0 and 1024 that don't exist
+	}
+}