// IsUniqueBits determines if a string has all unique chars (only works for ASCII)
// This solution doesn't utilize any additional data structures and has O(n) time complexity
func IsUniqueBits(s string) bool {

	s = strings.ToLower(s)
	var vector int32
	sBytes := []byte(s) // only for ASCII
	for _, sByte := range sBytes {
		index := sByte - 'a'
		mask := int32(1 << index)
		if (vector & mask) == mask {
			return false
		}
		vector = vector | mask
	}
	return true
}