advent-of-code/2023/day02_cubes_game.go
2023-12-02 14:21:57 +01:00

108 lines
2.6 KiB
Go

package _023
import (
"bufio"
"fmt"
"io"
"regexp"
"strconv"
"strings"
)
func Day02Part1(input io.Reader) (int, error) {
const maxRed, maxGreen, maxBlue = 12, 13, 14
scanner := bufio.NewScanner(input)
redReg := regexp.MustCompile(`(\d+) red`)
greenReg := regexp.MustCompile(`(\d+) green`)
blueReg := regexp.MustCompile(`(\d+) blue`)
sum := 0
LINES:
for scanner.Scan() {
line := strings.Split(scanner.Text(), ": ")
game := strings.Split(line[1], "; ")
for _, round := range game {
if matches := redReg.FindStringSubmatch(round); len(matches) == 2 {
red, err := strconv.Atoi(matches[1])
if err != nil {
return 0, fmt.Errorf("converting red to int: %w", err)
}
if red > maxRed {
continue LINES
}
}
if matches := greenReg.FindStringSubmatch(round); len(matches) == 2 {
green, err := strconv.Atoi(matches[1])
if err != nil {
return 0, fmt.Errorf("converting green to int: %w", err)
}
if green > maxGreen {
continue LINES
}
}
if matches := blueReg.FindStringSubmatch(round); len(matches) == 2 {
blue, err := strconv.Atoi(matches[1])
if err != nil {
return 0, fmt.Errorf("converting blue to int: %w", err)
}
if blue > maxBlue {
continue LINES
}
}
}
gameID, err := strconv.Atoi(strings.TrimPrefix(line[0], "Game "))
if err != nil {
return 0, fmt.Errorf("converting game ID to int: %w", err)
}
sum += gameID
}
return sum, nil
}
func Day02Part2(input io.Reader) (int, error) {
scanner := bufio.NewScanner(input)
redReg := regexp.MustCompile(`(\d+) red`)
greenReg := regexp.MustCompile(`(\d+) green`)
blueReg := regexp.MustCompile(`(\d+) blue`)
sum := 0
for scanner.Scan() {
line := strings.Split(scanner.Text(), ": ")
game := strings.Split(line[1], "; ")
maxRed, maxGreen, maxBlue := 0, 0, 0
for _, round := range game {
if matches := redReg.FindStringSubmatch(round); len(matches) == 2 {
red, err := strconv.Atoi(matches[1])
if err != nil {
return 0, fmt.Errorf("converting red to int: %w", err)
}
if red > maxRed {
maxRed = red
}
}
if matches := greenReg.FindStringSubmatch(round); len(matches) == 2 {
green, err := strconv.Atoi(matches[1])
if err != nil {
return 0, fmt.Errorf("converting green to int: %w", err)
}
if green > maxGreen {
maxGreen = green
}
}
if matches := blueReg.FindStringSubmatch(round); len(matches) == 2 {
blue, err := strconv.Atoi(matches[1])
if err != nil {
return 0, fmt.Errorf("converting blue to int: %w", err)
}
if blue > maxBlue {
maxBlue = blue
}
}
}
sum += maxRed * maxGreen * maxBlue
}
return sum, nil
}