feat: refactor some code and solve part two

internal/2015/DayFourteen/code.go

@@ -8,6 +8,17 @@ import (
 	"strings"
 )
 
+var reindeerPattern = regexp.MustCompile(`\w+ can fly (\d+) km/s for (\d+) seconds, but then must rest for (\d+) seconds\.`)
+
+const raceTime = 2503
+
+type Reindeer struct {
+	Speed    int
+	FlyTime  int
+	RestTime int
+	Points   int
+}
+
 func init() {
 	registry.Register("2015D14", ParseInput, PartOne, PartTwo)
 }
@@ -17,24 +28,37 @@ func ParseInput(filepath string) []string {
 	return strings.Split(string(content), "\n")
 }
 
-func calculateMaxDistance(data []string, time int) int {
+func parseReindeer(line string) Reindeer {
-	maxDistance := 0
+	matches := reindeerPattern.FindStringSubmatch(line)
-	pattern := regexp.MustCompile(`\w+ can fly (\d+) km/s for (\d+) seconds, but then must rest for (\d+) seconds\.`)
+	speed, _ := strconv.Atoi(matches[1])
+	flyTime, _ := strconv.Atoi(matches[2])
+	restTime, _ := strconv.Atoi(matches[3])
+	return Reindeer{Speed: speed, FlyTime: flyTime, RestTime: restTime}
+}
 
+func parseReindeers(data []string) []Reindeer {
+	reindeers := make([]Reindeer, 0, len(data))
 	for _, line := range data {
-		matches := pattern.FindStringSubmatch(line)
+		reindeers = append(reindeers, parseReindeer(line))
+	}
+	return reindeers
+}
 
-		speed, _ := strconv.Atoi(matches[1])
+func (reindeer Reindeer) distanceAtTime(time int) int {
-		flyTime, _ := strconv.Atoi(matches[2])
+	cycleTime := reindeer.FlyTime + reindeer.RestTime
-		restTime, _ := strconv.Atoi(matches[3])
+	fullCycles := time / cycleTime
-		cycleTime := flyTime + restTime
+	distance := fullCycles * reindeer.Speed * reindeer.FlyTime
+	remainingTime := time % cycleTime
+	distance += reindeer.Speed * min(remainingTime, reindeer.FlyTime)
+	return distance
+}
 
-		fullCycles := time / cycleTime
+func calculateMaxDistance(data []string, time int) int {
-		distance := fullCycles * speed * flyTime
+	reindeers := parseReindeers(data)
-
+	maxDistance := 0
-		remainingTime := time % cycleTime
-		distance += speed * min(remainingTime, flyTime)
 
+	for _, reindeer := range reindeers {
+		distance := reindeer.distanceAtTime(time)
 		if distance > maxDistance {
 			maxDistance = distance
 		}
@@ -43,10 +67,42 @@ func calculateMaxDistance(data []string, time int) int {
 	return maxDistance
 }
 
+func calculateMaxPoints(data []string, time int) int {
+	reindeers := parseReindeers(data)
+
+	for second := 1; second <= time; second++ {
+		maxDistance := 0
+		distances := make([]int, len(reindeers))
+
+		for idx := range reindeers {
+			distance := reindeers[idx].distanceAtTime(second)
+			distances[idx] = distance
+			if distance > maxDistance {
+				maxDistance = distance
+			}
+		}
+
+		for idx := range reindeers {
+			if distances[idx] == maxDistance {
+				reindeers[idx].Points++
+			}
+		}
+	}
+
+	maxPoints := 0
+	for idx := range reindeers {
+		if reindeers[idx].Points > maxPoints {
+			maxPoints = reindeers[idx].Points
+		}
+	}
+
+	return maxPoints
+}
+
 func PartOne(data []string) int {
-	return calculateMaxDistance(data, 2503)
+	return calculateMaxDistance(data, raceTime)
 }
 
 func PartTwo(data []string) int {
-	return 0
+	return calculateMaxPoints(data, raceTime)
 }