You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
127 lines
2.6 KiB
127 lines
2.6 KiB
package main
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"os"
|
|
"reflect"
|
|
"strings"
|
|
)
|
|
|
|
func main() {
|
|
var scannedSeats, currentSeats [][]rune
|
|
|
|
file, _ := os.Open("input.txt")
|
|
defer file.Close()
|
|
for scanner := bufio.NewScanner(file); scanner.Scan(); {
|
|
row := []rune{}
|
|
for _, r := range scanner.Text() {
|
|
row = append(row, r)
|
|
}
|
|
scannedSeats = append(scannedSeats, row)
|
|
}
|
|
|
|
// Part 1
|
|
|
|
currentSeats = scannedSeats
|
|
rounds:
|
|
for {
|
|
newSeats := [][]rune{}
|
|
for i := range currentSeats {
|
|
row := []rune{}
|
|
for j, r := range currentSeats[i] {
|
|
newRune := r
|
|
if os := occupiedAdjacent(currentSeats, position{i, j}); r == 'L' && os == 0 {
|
|
newRune = '#'
|
|
} else if r == '#' && os >= 4 {
|
|
newRune = 'L'
|
|
}
|
|
row = append(row, newRune)
|
|
}
|
|
newSeats = append(newSeats, row)
|
|
}
|
|
if reflect.DeepEqual(currentSeats, newSeats) {
|
|
break rounds
|
|
}
|
|
currentSeats = newSeats
|
|
}
|
|
|
|
fmt.Println("Part 1:", countOccupied(currentSeats))
|
|
|
|
// Part 2
|
|
|
|
currentSeats = scannedSeats
|
|
rounds2:
|
|
for {
|
|
newSeats := [][]rune{}
|
|
for i := range currentSeats {
|
|
row := []rune{}
|
|
for j, r := range currentSeats[i] {
|
|
newRune := r
|
|
if cs := canSeeAdjacent(currentSeats, position{i, j}); r == 'L' && cs == 0 {
|
|
newRune = '#'
|
|
} else if r == '#' && cs >= 5 {
|
|
newRune = 'L'
|
|
}
|
|
row = append(row, newRune)
|
|
}
|
|
newSeats = append(newSeats, row)
|
|
}
|
|
if reflect.DeepEqual(currentSeats, newSeats) {
|
|
break rounds2
|
|
}
|
|
currentSeats = newSeats
|
|
}
|
|
|
|
fmt.Println("Part 2:", countOccupied(currentSeats))
|
|
}
|
|
|
|
type position struct {
|
|
row, pos int
|
|
}
|
|
|
|
var dirs = []position{
|
|
{-1, -1}, {-1, 0}, {-1, 1}, {0, -1}, {0, 1}, {1, -1}, {1, 0}, {1, 1},
|
|
}
|
|
|
|
func direction(pos, dir position) position {
|
|
return position{pos.row + dir.row, pos.pos + dir.pos}
|
|
}
|
|
|
|
func isSafe(seats [][]rune, p position) bool {
|
|
return !(p.row < 0 || p.row >= len(seats) || p.pos < 0 || p.pos >= len(seats[p.row]))
|
|
}
|
|
|
|
func occupied(seats [][]rune, p position) bool {
|
|
return isSafe(seats, p) && seats[p.row][p.pos] == '#'
|
|
}
|
|
|
|
func occupiedAdjacent(seats [][]rune, pos position) (o int) {
|
|
for _, dir := range dirs {
|
|
if occupied(seats, direction(pos, dir)) {
|
|
o++
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
func canSee(seats [][]rune, p, dir position) bool {
|
|
return isSafe(seats, p) && seats[p.row][p.pos] != 'L' && (seats[p.row][p.pos] == '#' || canSee(seats, direction(p, dir), dir))
|
|
}
|
|
|
|
func canSeeAdjacent(seats [][]rune, pos position) (o int) {
|
|
for _, dir := range dirs {
|
|
if canSee(seats, direction(pos, dir), dir) {
|
|
o++
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
func countOccupied(seats [][]rune) (o int) {
|
|
for _, ro := range seats {
|
|
o += strings.Count(string(ro), "#")
|
|
}
|
|
return
|
|
}
|