func (h *HashSet) Put(value interface{}) {
	h.data[value] = struct{}{}
}
Put put value in a HashMap
package set
type HashSet struct {
	data map[interface{}]struct{}
}
func NewHashSet() *HashSet {
	s := &HashSet{
		data: make(map[interface{}]struct{}),
	}
	return s
}
func (h *HashSet) Size() int {
	return len(h.data)
}
func (h *HashSet) IsEmpty() bool {
	return len(h.data) == 0
}
func (h *HashSet) Clear() {
	h.data = make(map[interface{}]struct{})
}