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