day8 part2

day8/main.go

@@ -41,6 +41,11 @@ func main() {
 	slices.Sort(totals)
 	slices.Reverse(totals)
 	fmt.Printf("%v\n", totals[0]*totals[1]*totals[2])
+	xx, err := p.wireAll()
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("%d\n", xx)
 }
 
 func parsePlayground(lines []string) playground {
@@ -103,6 +108,81 @@ func (p *playground) wireClosest(n uint64) (map[string]uint, error) {
 	return circuits, nil
 }
 
+func (p *playground) wireAll() (int, error) {
+	edges, err := p.distances.Edges()
+	if err != nil {
+		return 0, err
+	}
+	slices.SortFunc(edges, func(e1, e2 graph.Edge[string]) int {
+		return e1.Properties.Weight - e2.Properties.Weight
+	})
+	circuitsInUse := 0
+	nextCircuit := uint(1)
+	circuits := map[string]uint{}
+	for _, edge := range edges {
+		sourceCircuit := circuits[edge.Source]
+		targetCircuit := circuits[edge.Target]
+		if sourceCircuit == 0 && targetCircuit == 0 {
+			circuits[edge.Source] = nextCircuit
+			circuits[edge.Target] = nextCircuit
+			nextCircuit++
+			circuitsInUse++
+			continue
+		}
+		if sourceCircuit == 0 {
+			circuits[edge.Source] = targetCircuit
+			if circuitsInUse == 1 {
+				count, _ := p.distances.Order()
+				if count == len(circuits) {
+					v1, _ := p.distances.Vertex(edge.Source)
+					v2, _ := p.distances.Vertex(edge.Target)
+					return v1.x * v2.x, nil
+				}
+			}
+			continue
+		}
+		if targetCircuit == 0 {
+			circuits[edge.Target] = sourceCircuit
+			if circuitsInUse == 1 {
+				count, _ := p.distances.Order()
+				if count == len(circuits) {
+					v1, _ := p.distances.Vertex(edge.Source)
+					v2, _ := p.distances.Vertex(edge.Target)
+					return v1.x * v2.x, nil
+				}
+			}
+			continue
+		}
+		if sourceCircuit == targetCircuit {
+			if circuitsInUse == 1 {
+				count, _ := p.distances.Order()
+				if count == len(circuits) {
+					v1, _ := p.distances.Vertex(edge.Source)
+					v2, _ := p.distances.Vertex(edge.Target)
+					return v1.x * v2.x, nil
+				}
+			}
+			continue
+		}
+		for k, v := range circuits {
+			if v == targetCircuit {
+				circuits[k] = sourceCircuit
+			}
+		}
+		circuitsInUse--
+		if circuitsInUse == 1 {
+			count, _ := p.distances.Order()
+			if count == len(circuits) {
+				v1, _ := p.distances.Vertex(edge.Source)
+				v2, _ := p.distances.Vertex(edge.Target)
+				return v1.x * v2.x, nil
+			}
+		}
+	}
+	v, _ := p.distances.Order()
+	return 0, fmt.Errorf("exhausted edges without reaching full connectivity %v", v)
+}
+
 type playground struct {
 	boxes     []box
 	distances graph.Graph[string, box]