func Index(vs []string, t string) int {
	for i, v := range vs {
		if v == t {
			return i
		}
	}
	return -1
}
func Index(vs []string, t string) int {
	for i, v := range vs {
		if v == t {
			return i
		}
	}
	return -1
}
func Index ( vs [ ] string , t string ) int { for i , v := range vs { if v == t { return i } } return - 1 }
// Index returns the first index of the target string t, or -1 if no match is found.
Index returns the first index of the target string t or - 1 if no match is found .