day 303: clock hand angles

day303/problem.go

@@ -19,3 +19,17 @@ func AngleClockHands(hh, mm int) int {
 	}
 	return int(math.Round(math.Abs(diffAngle)))
 }
+
+// TimesOverlappingHands returns all the [hh:mm] pairs with overlapping
+// clock hands by checking all possible 12*60 hour/minute possibilities.
+func TimesOverlappingHands() [][]int {
+	var result [][]int
+	for h := 0; h < 12; h++ {
+		for m := 0; m < 60; m++ {
+			if angle := AngleClockHands(h, m); angle == 0 {
+				result = append(result, []int{h, m})
+			}
+		}
+	}
+	return result
+}

day303/problem_test.go

@@ -1,6 +1,9 @@
 package day303
 
-import "testing"
+import (
+	"reflect"
+	"testing"
+)
 
 // nolint
 var testcases = []struct {
@@ -37,3 +40,20 @@ func BenchmarkAngleClockHands(b *testing.B) {
 		}
 	}
 }
+
+func TestTimesOverlappingHands(t *testing.T) {
+	t.Parallel()
+	result := TimesOverlappingHands()
+	expected := [][]int{
+		{0, 0}, {1, 5}, {2, 10}, {3, 15}, {4, 20}, {5, 25}, {6, 30}, {7, 35}, {8, 40}, {9, 45}, {10, 50}, {11, 55},
+	}
+	if !reflect.DeepEqual(result, expected) {
+		t.Errorf("Expected %v, got %v", result, expected)
+	}
+}
+
+func BenchmarkTimesOverlappingHands(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		TimesOverlappingHands()
+	}
+}