advent-of-code/2023/day01_trebuchet.go

104 lines
1.7 KiB
Go

package _023
import (
"bufio"
"io"
"regexp"
"strconv"
)
func D01Part1(input io.Reader) (int, error) {
scanner := bufio.NewScanner(input)
sum := 0
for scanner.Scan() {
begValue, endValue := 0, 0
line := scanner.Text()
for i := 0; i < len(line); i++ {
beg := line[i]
if val, err := strconv.Atoi(string(beg)); err == nil && begValue == 0 {
begValue = val
}
j := len(line) - 1 - i
end := line[j]
if val, err := strconv.Atoi(string(end)); err == nil && endValue == 0 {
endValue = val
}
if begValue > 0 && endValue > 0 {
break
}
}
sum += begValue*10 + endValue
}
return sum, nil
}
func D01Part2(input io.Reader) (int, error) {
reg, err := regexp.Compile(`[0-9]|one|two|three|four|five|six|seven|eight|nine`)
if err != nil {
return 0, err
}
scanner := bufio.NewScanner(input)
sum := 0
for scanner.Scan() {
line := scanner.Text()
begValue, endValue := 0, 0
for i := 0; i < len(line); i++ {
beg := reg.FindString(line[:i])
if value := translate(beg); value > 0 && begValue == 0 {
begValue = value
}
j := len(line) - i - 1
end := reg.FindString(line[j:])
if value := translate(end); value > 0 && endValue == 0 {
endValue = value
}
if begValue > 0 && endValue > 0 {
break
}
}
if begValue == 0 {
begValue = endValue
}
sum += begValue*10 + endValue
}
return sum, nil
}
func translate(digit string) int {
switch digit {
case "1", "one":
return 1
case "2", "two":
return 2
case "3", "three":
return 3
case "4", "four":
return 4
case "5", "five":
return 5
case "6", "six":
return 6
case "7", "seven":
return 7
case "8", "eight":
return 8
case "9", "nine":
return 9
default:
return 0
}
}