forked from timtadh/data-structures
/
ops.go
86 lines (77 loc) · 1.65 KB
/
ops.go
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package set
import (
"github.com/timtadh/data-structures/hashtable"
"github.com/timtadh/data-structures/types"
)
func newSetBestType(a types.Set, sizeHint int) types.Set {
switch a.(type) {
case *MapSet:
return NewMapSet(NewSortedSet(sizeHint))
case *SortedSet:
return NewSortedSet(sizeHint)
case *SetMap:
return NewSetMap(hashtable.NewLinearHash())
default:
return NewSortedSet(sizeHint)
}
}
func Union(a, b types.Set) (types.Set, error) {
c := newSetBestType(a, a.Size()+b.Size())
err := c.Extend(a.Items())
if err != nil {
return nil, err
}
err = c.Extend(b.Items())
if err != nil {
return nil, err
}
return c, nil
}
func Intersect(a, b types.Set) (types.Set, error) {
c := newSetBestType(a, a.Size()+b.Size())
for item, next := a.Items()(); next != nil; item, next = next() {
if b.Has(item) {
err := c.Add(item)
if err != nil {
return nil, err
}
}
}
return c, nil
}
// Unions s with o and returns a new Sorted Set
func Subtract(a, b types.Set) (types.Set, error) {
c := newSetBestType(a, a.Size()+b.Size())
for item, next := a.Items()(); next != nil; item, next = next() {
if !b.Has(item) {
err := c.Add(item)
if err != nil {
return nil, err
}
}
}
return c, nil
}
func Subset(a, b types.Set) bool {
if a.Size() > b.Size() {
return false
}
for item, next := a.Items()(); next != nil; item, next = next() {
if !b.Has(item) {
return false
}
}
return true
}
func ProperSubset(a, b types.Set) bool {
if a.Size() >= b.Size() {
return false
}
return Subset(a, b)
}
func Superset(a, b types.Set) bool {
return Subset(b, a)
}
func ProperSuperset(a, b types.Set) bool {
return ProperSubset(b, a)
}