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set.go
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set.go
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package genericsds
type Set[T comparable] struct {
storage map[T]struct{}
}
// Create a new generic-typed set. T must be comparable. You need to use this function
// to create new sets. Set[int]{} will not work.
func NewSet[T comparable]() Set[T] {
return Set[T]{
storage: make(map[T]struct{}),
}
}
func NewSetCollection[T comparable]() Collection[T] {
return NewSet[T]()
}
// Add an item to the set. Has no effect if the item already exists.
func (r Set[T]) Add(item T) {
r.storage[item] = struct{}{}
}
// Determine if the set is empty
func (r Set[T]) IsEmpty() bool {
return len(r.storage) == 0
}
// Returns true if the set contains the specified item.
func (r Set[T]) Contains(item T) bool {
_, has := r.storage[item]
return has
}
// Removes the specified item from the set. Has no effect if the item is not present.
func (r Set[T]) Remove(item T) {
delete(r.storage, item)
}
// Returns the number of items in the set.
func (r Set[T]) Size() int {
return len(r.storage)
}
// Adds all items from the specified set to this one. This function mutates the set.
func (r Set[T]) Merge(s Set[T]) {
for k := range s.storage {
r.Add(k)
}
}
// Iterate through all items, call the delegate function on each
func (r Set[T]) ForEach(f func(item T)) {
for k := range r.storage {
f(k)
}
}
// Creates a new set from all items in this one and the one specified. It is
// non-destructive to both sets involved.
func (r Set[T]) Union(s Set[T]) Set[T] {
newSet := NewSet[T]()
for k := range r.storage {
newSet.Add(k)
}
for k := range s.storage {
newSet.Add(k)
}
return newSet
}
// Creates a new set with all items common to this one and the one specified. It is
// non-destructive to both sets involved.
func (r Set[T]) Intersection(s Set[T]) Set[T] {
newSet := NewSet[T]()
var shorterSet *Set[T]
var longerSet *Set[T]
if r.Size() > s.Size() {
shorterSet = &s
longerSet = &r
} else {
shorterSet = &r
longerSet = &s
}
for k := range shorterSet.storage {
if longerSet.Contains(k) {
newSet.Add(k)
}
}
return newSet
}
// Creates a new set with the items in this one less any of the items in the specified
// set. It is non-destructive to both sets involved.
func (r Set[T]) Difference(s Set[T]) Set[T] {
newSet := NewSet[T]()
for k := range r.storage {
newSet.Add(k)
}
for k := range s.storage {
newSet.Remove(k)
}
return newSet
}