81 lines
1.3 KiB
Go
81 lines
1.3 KiB
Go
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"sort"
|
|
|
|
"github.com/jdkaplan/advent-of-code/aoc"
|
|
)
|
|
|
|
func main() {
|
|
lines := aoc.Input().ReadLines("day10.txt")
|
|
fmt.Println(part1(lines))
|
|
fmt.Println(part2(lines))
|
|
}
|
|
|
|
func part1(lines []string) (score int) {
|
|
for _, l := range lines {
|
|
points, _ := parseLine(l)
|
|
score += points
|
|
}
|
|
return
|
|
}
|
|
|
|
func part2(lines []string) int {
|
|
var scores []int
|
|
for _, l := range lines {
|
|
points, stack := parseLine(l)
|
|
if points == 0 {
|
|
scores = append(scores, autocomplete(stack))
|
|
}
|
|
}
|
|
sort.Ints(scores)
|
|
return scores[(len(scores)-1)/2]
|
|
}
|
|
|
|
func parseLine(line string) (score int, stack []rune) {
|
|
for _, c := range line {
|
|
switch c {
|
|
case '(', '[', '{', '<':
|
|
stack = append([]rune{c}, stack...)
|
|
case ')':
|
|
if stack[0] != '(' {
|
|
return 3, stack
|
|
}
|
|
stack = stack[1:]
|
|
case ']':
|
|
if stack[0] != '[' {
|
|
return 57, stack
|
|
}
|
|
stack = stack[1:]
|
|
case '}':
|
|
if stack[0] != '{' {
|
|
return 1197, stack
|
|
}
|
|
stack = stack[1:]
|
|
case '>':
|
|
if stack[0] != '<' {
|
|
return 25137, stack
|
|
}
|
|
stack = stack[1:]
|
|
}
|
|
}
|
|
return 0, stack
|
|
}
|
|
|
|
func autocomplete(stack []rune) (score int) {
|
|
for _, c := range stack {
|
|
score *= 5
|
|
switch c {
|
|
case '(':
|
|
score += 1
|
|
case '[':
|
|
score += 2
|
|
case '{':
|
|
score += 3
|
|
case '<':
|
|
score += 4
|
|
}
|
|
}
|
|
return
|
|
}
|