package secret var sign = map[int]string{ 1 << 0: "wink", 1 << 1: "double blink", 1 << 2: "close your eyes", 1 << 3: "jump", } const rev = 1 << 4 func reverse(s []string) []string { for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 { s[i], s[j] = s[j], s[i] } return s } func Handshake(n int) []string { if n <= 0 { return nil } var s []string for i := 1; i < rev; i <<= 1 { if n&i != 0 { s = append(s, sign[i]) } } if n&rev != 0 { s = reverse(s) } return s }