roll my own parser for each round for a little extra speed

02/main.go

@@ -40,6 +40,35 @@ type game struct {
 	blue  int
 }
 
+func parseRound(line string) game {
+	g := game{}
+	n := []byte{}
+	for i := 0; i < len(line); i++ {
+		switch line[i] {
+		case ' ':
+			continue
+		case ',':
+			i++
+			continue
+		case '1', '2', '3', '4', '5', '6', '7', '8', '9', '0':
+			n = append(n, line[i])
+		case 'r':
+			g.red = mustAtoi(string(n))
+			n = []byte{}
+			i += 4
+		case 'g':
+			g.green = mustAtoi(string(n))
+			n = []byte{}
+			i += 6
+		case 'b':
+			g.blue = mustAtoi(string(n))
+			n = []byte{}
+			i += 5
+		}
+	}
+	return g
+}
+
 func partOne() {
 	scanner := makeScanner(false)
 
@@ -56,20 +85,7 @@ func partOne() {
 		round++
 		_, draws, _ := strings.Cut(line, ": ")
 		for _, draws := range strings.Split(draws, "; ") {
-			iter := strings.Split(draws, " ")
-			g := game{}
-			for i := 0; i < len(iter); i++ {
-				seen := mustAtoi(iter[i])
-				i++
-				switch iter[i][0] {
-				case 'r':
-					g.red = seen
-				case 'g':
-					g.green = seen
-				case 'b':
-					g.blue = seen
-				}
-			}
+			g := parseRound(draws)
 			if g.red > max.red || g.blue > max.blue || g.green > max.green {
 				ok = false
 			}
@@ -90,20 +106,7 @@ func partTwo() {
 		_, draws, _ := strings.Cut(line, ": ")
 		max := game{}
 		for _, draws := range strings.Split(draws, "; ") {
-			iter := strings.Split(draws, " ")
-			g := game{}
-			for i := 0; i < len(iter); i++ {
-				seen := mustAtoi(iter[i])
-				i++
-				switch iter[i][0] {
-				case 'r':
-					g.red = seen
-				case 'g':
-					g.green = seen
-				case 'b':
-					g.blue = seen
-				}
-			}
+			g := parseRound(draws)
 			if g.red > max.red {
 				max.red = g.red
 			}