day 08 part 2

08/main.go

@@ -76,13 +76,55 @@ func do(test bool) (int, int) {
 	// sort distances by length
 	sort.Slice(connections, func(i, j int) bool { return connections[i].Length < connections[j].Length })
 
+	threshold := 1000
+
 	if test {
-		connections = connections[:10]
-	} else {
-		connections = connections[:1000]
+		threshold = 10
 	}
 
+	var res1, res2 int
+
 	for ii := range connections {
+		if ii == threshold {
+			roots := []*Node{}
+
+			for ii := range points {
+				pp := &points[ii]
+				if pp.GetRoot() == pp {
+					roots = append(roots, pp)
+				}
+			}
+
+			sort.Slice(roots, func(i, j int) bool { return roots[i].Size > roots[j].Size })
+
+			res1 = roots[0].Size * roots[1].Size * roots[2].Size
+
+			fmt.Println(res1)
+
+		} else if ii > threshold {
+			cc := connections[ii-1]
+			// check wether it is one big circuit
+			root := points[0].GetRoot()
+
+			multipleCircuits := false
+
+			for jj := range points[1:] {
+				pp := &points[jj]
+				if pp.GetRoot() != root {
+					multipleCircuits = true
+					break
+				}
+			}
+
+			if !multipleCircuits {
+				res2 = cc.P1.X * cc.P2.X
+
+				fmt.Println(res2)
+
+				break
+			}
+		}
+
 		cc := &connections[ii]
 
 		root1 := cc.P1.GetRoot()
@@ -95,26 +137,11 @@ func do(test bool) (int, int) {
 		}
 	}
 
-	roots := []*Node{}
-
-	for ii := range points {
-		pp := &points[ii]
-		if pp.GetRoot() == pp {
-			roots = append(roots, pp)
-		}
-	}
-
-	sort.Slice(roots, func(i, j int) bool { return roots[i].Size > roots[j].Size })
-
-	res1 := roots[0].Size * roots[1].Size * roots[2].Size
-
-	fmt.Println(res1)
-
-	return res1, 0
+	return res1, res2
 }
 
 func main() {
-	if r1, r2 := do(true); r1 == 40 && r2 == 0 {
+	if r1, r2 := do(true); r1 == 40 && r2 == 25272 {
 		do(false)
 	}
 }