diff --git a/internal/2016/DayFive/code.go b/internal/2016/DayFive/code.go new file mode 100644 index 0000000..861a289 --- /dev/null +++ b/internal/2016/DayFive/code.go @@ -0,0 +1,45 @@ +package dayfive + +import ( + "advent-of-code/internal/registry" + "crypto/md5" + "fmt" + "os" + "strconv" +) + +func init() { + registry.Register("2016D5", ParseInput, PartOne, PartTwo) +} + +func ParseInput(filepath string) string { + content, _ := os.ReadFile(filepath) + return string(content) +} + +func PartOne(data string) int { + doorIDBytes := []byte(data) + password := make([]byte, 0, 8) + index := 0 + hexChars := "0123456789abcdef" + var buffer []byte + + for len(password) < 8 { + buffer = strconv.AppendInt(buffer[:0], int64(index), 10) + input := append(doorIDBytes, buffer...) + hash := md5.Sum(input) + + if hash[0] == 0 && hash[1] == 0 && hash[2] < 16 { + char := hexChars[hash[2]&0x0F] + password = append(password, char) + } + index++ + } + + fmt.Println(string(password)) + return 0 +} + +func PartTwo(data string) int { + return 0 +}