Files
advent-of-gode/2023/04/code.go
2023-12-04 16:35:41 +02:00

104 lines
1.9 KiB
Go

package main
import (
"regexp"
"strings"
"github.com/jpillora/puzzler/harness/aoc"
)
func main() {
aoc.Harness(run)
}
// on code change, run will be executed 4 times:
// 1. with: false (part1), and example input
// 2. with: true (part2), and example input
// 3. with: false (part1), and user input
// 4. with: true (part2), and user input
// the return value of each run is printed to stdout
func run(part2 bool, input string) any {
gameIdRxp := regexp.MustCompile(`Card +(?P<ID>\d+): ?(?P<Winning>.*) \| ?(?P<Drawn>.*)`)
if part2 {
lines := strings.Split(strings.Trim(input, "\n"), "\n")
points := make([]int, len(lines))
for i, line := range lines {
matches := gameIdRxp.FindStringSubmatch(line)
if len(matches) == 0 {
continue
}
winning := strings.Split(matches[2], " ")
drawn := strings.Split(matches[3], " ")
points[i] = 0
for _, win := range winning {
if win == "" {
continue
}
for _, draw := range drawn {
if win == draw {
points[i] += 1
}
}
}
}
copies := make([]int, len(points))
for i := range points {
copies[i] = 1
}
for i, p := range points {
for j := i + 1; int(j) <= int(i)+p; j++ {
if j < len(copies) {
copies[j] += copies[i]
}
}
}
totalCards := int(0)
for _, count := range copies {
totalCards += count
}
return totalCards
}
// solve part 1 here
sum := 0
for _, line := range strings.Split(input, "\n") {
matches := gameIdRxp.FindStringSubmatch(line)
if len(matches) == 0 {
continue
}
winning := strings.Split(matches[2], " ")
drawn := strings.Split(matches[3], " ")
points := 0
for _, win := range winning {
if win == "" {
continue
}
for _, draw := range drawn {
if win == draw {
if points == 0 {
points = 1
} else {
points = points * 2
}
}
}
}
sum += points
}
return sum
}