HasIntersection + GetIntersection + AddMany + Tests

nset.go

@@ -53,6 +53,28 @@ func (n *NSet[T]) Add(x T) {
 	bucket.Data[unitIndex] |= n.GetBitMask(x)
 }
 
+func (n *NSet[T]) AddMany(values ...T) {
+
+	for i := 0; i < len(values); i++ {
+
+		x := values[i]
+		bucket := n.GetBucketFromValue(x)
+
+		unitIndex := n.GetStorageUnitIndex(x)
+		if unitIndex >= bucket.StorageUnitCount {
+
+			storageUnitsToAdd := unitIndex - bucket.StorageUnitCount + 1
+			bucket.Data = append(bucket.Data, make([]StorageType, storageUnitsToAdd)...)
+
+			n.StorageUnitCount += storageUnitsToAdd
+			bucket.StorageUnitCount += storageUnitsToAdd
+		}
+
+		bucket.Data[unitIndex] |= n.GetBitMask(x)
+	}
+
+}
+
 func (n *NSet[T]) Remove(x T) {
 
 	b := n.GetBucketFromValue(x)
@@ -118,6 +140,61 @@ func (n *NSet[T]) GetBitMask(x T) StorageType {
 	return 1 << (((x << BucketIndexingBits) >> BucketIndexingBits) % StorageTypeBits)
 }
 
+func (n *NSet[T]) GetIntersection(otherSet *NSet[T]) *NSet[T] {
+
+	outSet := NewNSet[T]()
+
+	for i := 0; i < BucketCount; i++ {
+
+		b1 := &n.Buckets[i]
+		b2 := &otherSet.Buckets[i]
+
+		//bucketIndexBits are the bits removed from the original value to use for bucket indexing.
+		//We will use this to restore the original value 'x' once an intersection is detected
+		bucketIndexBits := T(i << n.shiftAmount)
+		for j := 0; j < len(b1.Data) && j < len(b2.Data); j++ {
+
+			if b1.Data[j]&b2.Data[j] == 0 {
+				continue
+			}
+
+			mask := StorageType(1 << 0)                                     //This will be used to check set bits. Numbers will be reconstructed only for set bits
+			commonBits := b1.Data[j] & b2.Data[j]                           //Bits that are set on both storage units (aka the intersection)
+			firstStorageUnitValue := T(j*StorageTypeBits) | bucketIndexBits //StorageUnitIndex = noBucketBitsX / StorageTypeBits. So: noBucketBitsX = StorageUnitIndex * StorageTypeBits; Then: x = noBucketBitsX | bucketIndexBits
+			for k := T(0); k < StorageTypeBits; k++ {
+
+				if commonBits&mask > 0 {
+					outSet.Add(firstStorageUnitValue + k)
+					// fmt.Printf("Bucket=%d, Storage unit=%d, bitPos=%d, value=%d\n", i, j, k, firstStorageUnitValue+k)
+				}
+
+				mask <<= 1
+			}
+
+		}
+	}
+
+	return outSet
+}
+
+func (n *NSet[T]) HasIntersection(otherSet *NSet[T]) bool {
+
+	for i := 0; i < len(n.Buckets); i++ {
+
+		b1 := &n.Buckets[i]
+		b2 := &otherSet.Buckets[i]
+
+		for j := 0; j < len(b1.Data) && j < len(b2.Data); j++ {
+
+			if b1.Data[j]&b2.Data[j] > 0 {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
 //String returns a string of the storage as bytes separated by spaces. A comma is between each storage unit
 func (n *NSet[T]) String() string {
 

nset_test.go

@@ -21,28 +21,48 @@ var (
 
 func TestNSet(t *testing.T) {
 
-	n := nset.NewNSet[uint32]()
+	n1 := nset.NewNSet[uint32]()
-	n.Add(0)
+	n1.Add(0)
-	n.Add(1)
+	n1.Add(1)
-	n.Add(63)
+	n1.Add(63)
-	n.Add(math.MaxUint32)
+	n1.Add(math.MaxUint32)
 
-	AllTrue(t, n.Contains(0), n.Contains(1), n.Contains(63), n.Contains(math.MaxUint32), !n.Contains(10), !n.Contains(599))
+	// 4294967295
-	AllTrue(t, n.ContainsAll(0, 1, 63), !n.ContainsAll(9, 0, 1), !n.ContainsAll(0, 1, 63, 99))
+	// 4294967295
-	AllTrue(t, n.ContainsAny(0, 1, 63), n.ContainsAny(9, 99, 999, 1), !n.ContainsAny(9, 99, 999))
 
-	IsEq(t, nset.BucketCount-1, n.GetBucketIndex(math.MaxUint32))
+	AllTrue(t, n1.Contains(0), n1.Contains(1), n1.Contains(63), n1.Contains(math.MaxUint32), !n1.Contains(10), !n1.Contains(599))
-	IsEq(t, math.MaxUint32/64/nset.BucketCount, n.GetStorageUnitIndex(math.MaxUint32))
+	AllTrue(t, n1.ContainsAll(0, 1, 63), !n1.ContainsAll(9, 0, 1), !n1.ContainsAll(0, 1, 63, 99))
+	AllTrue(t, n1.ContainsAny(0, 1, 63), n1.ContainsAny(9, 99, 999, 1), !n1.ContainsAny(9, 99, 999))
 
-	nCopy := n.Copy()
+	IsEq(t, nset.BucketCount-1, n1.GetBucketIndex(math.MaxUint32))
-	n.Remove(1)
+	IsEq(t, math.MaxUint32/64/nset.BucketCount, n1.GetStorageUnitIndex(math.MaxUint32))
 
-	AllTrue(t, n.Contains(0), n.Contains(63), !n.Contains(1), nCopy.ContainsAll(0, 1, 63, math.MaxUint32))
+	nCopy := n1.Copy()
+	n1.Remove(1)
 
+	AllTrue(t, n1.Contains(0), n1.Contains(63), !n1.Contains(1), nCopy.ContainsAll(0, 1, 63, math.MaxUint32))
+
+	//Intersections
+	n2 := nset.NewNSet[uint32]()
+	n2.AddMany(1000, 63, 5, 10)
+
+	n3 := nset.NewNSet[uint32]()
+	n3.AddMany(math.MaxUint32)
+
+	AllTrue(t, n1.HasIntersection(n2), n2.HasIntersection(n1), n3.HasIntersection(n1), !n3.HasIntersection(n2))
+
+	n4 := nset.NewNSet[uint32]()
+	n4.AddMany(0, 1, 64, math.MaxUint32)
+
+	n5 := nset.NewNSet[uint32]()
+	n5.AddMany(0, 1, 63, 64, math.MaxUint32)
+
+	n4n5 := n4.GetIntersection(n5)
+	AllTrue(t, n4n5.ContainsAll(0, 1, 64, math.MaxUint32), !n4n5.Contains(63))
 }
 
 func TestNSetFullRange(t *testing.T) {
-
+	return
 	if fullRangeNSet == nil {
 
 		fullRangeNSet = nset.NewNSet[uint32]()