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Add GetDifference method

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bloeys
2024-09-09 07:47:36 +04:00
parent 95b3af20e8
commit 17b8c38162
2 changed files with 61 additions and 9 deletions
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39
nset.go
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@ -165,6 +165,8 @@ func (n *NSet[T]) GetBitMask(x T) StorageType {
return 1 << FastModPower2(((x<<BucketIndexingBits)>>BucketIndexingBits), StorageTypeBits)
}
// Union does n1=Union(n1, n2), so the current set will be updated
// such that its a union of its old value and the passed set
func (n *NSet[T]) Union(otherSet *NSet[T]) {
for i := 0; i < BucketCount; i++ {
@ -192,6 +194,8 @@ func (n *NSet[T]) Union(otherSet *NSet[T]) {
}
}
// GetIntersection returns a new set that's the intersection between
// this set and the passed set
func (n *NSet[T]) GetIntersection(otherSet *NSet[T]) *NSet[T] {
outSet := NewNSet[T]()
@ -225,6 +229,41 @@ func (n *NSet[T]) GetIntersection(otherSet *NSet[T]) *NSet[T] {
return outSet
}
// GetDifference returns a new set that contains the elements in this set
// that are not in the passed set.
//
// For example, if s1=(1,2,3,4,5) and s2=(1,3,4), the output is
// s3=Diff(s1,s2)=(2,5)
func (n *NSet[T]) GetDifference(otherSet *NSet[T]) *NSet[T] {
outSet := NewNSet[T]()
for i := 0; i < BucketCount; i++ {
b1 := &n.Buckets[i]
b2 := &otherSet.Buckets[i]
outSet.StorageUnitCount += b1.StorageUnitCount
newB := &outSet.Buckets[i]
newB.StorageUnitCount = b1.StorageUnitCount
newB.Data = make([]StorageType, newB.StorageUnitCount)
for j := uint32(0); j < b1.StorageUnitCount && j < b2.StorageUnitCount; j++ {
newStorage := b1.Data[j] & (^b2.Data[j])
newB.Data[j] = newStorage
outSet.SetBits += uint64(bits.OnesCount64(uint64(newStorage)))
}
if b1.StorageUnitCount > b2.StorageUnitCount {
copy(newB.Data[b2.StorageUnitCount:], b1.Data[b2.StorageUnitCount:])
}
}
return outSet
}
// GetAllElements returns all the added numbers added to NSet.
//
// NOTE: Be careful with this if you have a lot of elements in NSet because NSet is compressed while the returned array is not.

21
nset_test.go
View File

@ -112,6 +112,21 @@ func TestNSet(t *testing.T) {
n8Elements := n8.GetAllElements()
AllTrue(t, len(n8Elements) == 5, n8Elements[0] == 0, n8Elements[1] == 1, n8Elements[2] == 55, n8Elements[3] == 1000, n8Elements[4] == 10000)
// GetDifference
nDiff1 := nset.NewNSet[uint32]()
nDiff1.AddMany(1, 2, 3)
nDiff2 := nset.NewNSet[uint32]()
nDiff2.AddMany(1, 3, 4)
nDiff3 := nDiff1.GetDifference(nDiff2)
AllTrue(t, nDiff3.SetBits == 1, nDiff3.StorageUnitCount == 1, nDiff3.Contains(2), !nDiff3.ContainsAny(1, 3, 4))
nDiff1.AddMany(1, 2, 3, 4, 5, math.MaxUint32)
nDiff3 = nDiff1.GetDifference(nDiff2)
AllTrue(t, nDiff3.SetBits == 2, nDiff3.ContainsAll(2, 5, math.MaxUint32), !nDiff3.ContainsAny(1, 3, 4))
}
func TestNSetFullRange(t *testing.T) {
@ -151,16 +166,14 @@ func TestNSetFullRange(t *testing.T) {
func AllTrue(t *testing.T, values ...bool) (success bool) {
success = true
for i := 0; i < len(values); i++ {
if !values[i] {
t.Fatalf("Expected 'true' but got 'false'\n")
success = false
return false
}
}
return success
return true
}
func IsEq[T comparable](t *testing.T, expected, val T) bool {