case n == 1:
		return bytealg.LastIndexByte(s, sep[0])
	case n == len(s):
		if Equal(s, sep) {
			return 0
		}
		return -1
	case n > len(s):
		return -1
	}
	return bytealg.LastIndexRabinKarp(s, sep)
}

// LastIndexByte returns the index of the last instance of c in s, or -1 if c is not present in s.
func LastIndexByte(s []byte, c byte) int {
	return bytealg.LastIndexByte(s, c)
}