Add method ContainsUnit to type Set

intervalset.go

@@ -271,6 +271,13 @@ func (x Set[E]) Contains(r Interval[E]) bool {
 	return len(x) != 0 && x[0].Low.Compare(r.Low) <= 0 && x[0].High.Compare(r.High) >= 0 && r.Low.Compare(r.High) < 0
 }
 
+// ContainsUnit reports whether x contains a single element v.
+// Faster than x.Contains(Unit(v)).
+func (x Set[E]) ContainsUnit(v E) bool {
+	x = x[sort.Search(len(x), func(i int) bool { return x[i].High.Compare(v) > 0 }):]
+	return len(x) != 0 && x[0].Low.Compare(v) <= 0
+}
+
 // Equal reports whether x is identical to y.
 func (x Set[E]) Equal(y Set[E]) bool {
 	return slices.EqualFunc(x, y, Interval[E].Equal)

intervalset_test.go

@@ -163,14 +163,14 @@ func TestContains(t *testing.T) {
 	s := Set[E]{{1, 3}, {5, 7}}
 
 	assertions := []bool{
-		s.Contains(Unit[E](0)) == false,
-		s.Contains(Unit[E](1)) == true,
-		s.Contains(Unit[E](2)) == true,
-		s.Contains(Unit[E](3)) == false,
-		s.Contains(Unit[E](4)) == false,
-		s.Contains(Unit[E](5)) == true,
-		s.Contains(Unit[E](6)) == true,
-		s.Contains(Unit[E](7)) == false,
+		s.ContainsUnit(0) == false,
+		s.ContainsUnit(1) == true,
+		s.ContainsUnit(2) == true,
+		s.ContainsUnit(3) == false,
+		s.ContainsUnit(4) == false,
+		s.ContainsUnit(5) == true,
+		s.ContainsUnit(6) == true,
+		s.ContainsUnit(7) == false,
 		s.Contains(Range[E](1, 3)) == true,
 		s.Contains(Range[E](3, 5)) == false,
 		s.Contains(Range[E](5, 7)) == true,