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day24

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This commit is contained in:
Adam Wick
2022-12-25 22:52:55 -08:00
parent 8792e5275a
commit b9805cf916
4 changed files with 349 additions and 0 deletions
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6
inputs/example.24 Normal file
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#.######
#>>.<^<#
#.<..<<#
#>v.><>#
#<^v^^>#
######.#

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#.########################################################################################################################
#<^>^<^^<v><vv^v^<^vv>^<^v>vv^v<<v<>^>^v<>v<<<.^<>^>v^><v<^...>>>>.^>>>v<.^^^^^>.v.v<v.><^<v<<v<>.<v.v<><vv.v>v>v<<<<<.<<#
#<>^^^v<.v<<v.v.vv.v^v>v<>.>vv>^>vv>^^><<<v>><v>><>.v.v>><><<>>vv>^^v<v^v><^<.><vv<.v<v>^^<v>^>^>^<v<>.<^.^<.>^v<<<<v^^.>#
#<v..^^>><<vvv><v^><>.>^^^><<>^><>>>^v<>><>^<v<<>>>v^v>.^v<v^>><vvv^<<.><v<.v<^>.v<..>^^^>><^v<v<v>v><>>>vvv^<<^v^>v.^v^<#
#<.^vv<^<.>>>>v<v^vv^v.v.v>>>^v<<<v^^<v<^<>.v<><v.v^<<^><><v^<<v.>><v><vv>^.<^<^v.v>>vv<>>vv^.^.><vv<^^^^<v^v<v>vv.v.><v>#
#<><^>v.^<v^<vv>vvv>>^v<v..vv.><>^>^v<<v.<v^...vv>>><^<^<^>v^^^><v<^<v<^.^<.^v><<v<.<>^<>v^.<>>.><^<^><><vv>vv^vv>><<><.<#
#.^^^^^^v^v.<<><>vv<>.>^v<v>^>.<>v.^^<><>^<>^v^^.<v<vv>>v<^<^><v<>.<v>^<^vvv<>^<^v^^.>.^.><<>v>v^>^^>vv^v>v.^vv<v^>>^^v><#
#<<^<<v>^<v^>>>v><^.^<.<>^.><v>vv<<.>v<^^v>vv>>>^<<>^<v<v<^<^.^^<><<<<^>v^>vv>^vv^v<.>v^^vv^<v^<v><>><v^<>^v<v><vv>^.<^v<#
#<<>.v^<v>^<>>v><<><vvvvv^><<<<>^<.<<>><^<v>>^<<^.v<<.>>><v<^.v.v<<v>>^><^v<>><^>>v>>>.^>>v^<^.<v>vv..v^^vvv^vv<>^<v<<>.>#
#><.v.^><vv.>>>>><.>.vv^<<>v><^<<v.<><>.v<v><<.>>v>>v<^.^^^<^^<v>^^<<>>><^>><^>^<.<v^v<v^><v<.<^^.>>^^<v.v<><v<>^^<.^<>v>#
#<<>v<^<.<<.>vv<.><>.vvvv<^.<<>><<v>>^^>v>^v>v<^^v.<^v<>vv^<><<>vv<v<^^<<><v>^<vv.^<>v<>.><vv>>vv^.>.>v>v>^v>^.><v<.v><^>#
#>.>>vv>><<>^v^^v>^<<.^^>>><v<v>>><<^^^<^vv<>v<v^>.<^<^<>v<^><>v.v^.>>v^^^^>.v.><v^^^vv<^>v^.^>v<>v.^^.^^v^v<v>>.^><<.^<>#
#<>v.^>>>>^^^>v<^<>v>^>v>vv^^>v.v<>>.>^><<>v^v.<v>^..v.>vv.^>^^v<v^^v>vvvvv>>^<^v.<>><<.v^>vv>>>vv><^.><.<^^^v^>^v<>v<v^>#
#<^<v^.>>.^<^^v^v.<v<<vv^.^.><vv^vv<>v^>.<.<<^<vv^>><<^^v^v^<v^vv.^^^>vv^<>v^>v^vv<>v.^v.<>^>vv>.^<^.v.>v>v>>v<v<^v>><v<<#
#>.<<>^^vvv>>v^^>^<^>.<<.v^>vv>>v<vv<<^v.<.v^^^.^>v>>.>>.^<<^v>.vvv><<<>^.^v>vvv^^^^<vv.><v<>v<<<><^^<v<.><<^><<>><><v^<<#
#<<<<..^v>v^>v^>^.<<^<>>v.vv>>>^^v^.vv^>><<<<.<<>^>^v>><>.>><>^><v^<v<^^v^>^>^^>>v>^>v.<v>>^<<^><<v>^v^<>v<>^^>>v<vv^vv>.#
#..^>^v.>.<^>^>.v>>.<<..<<>v^vvv<<vvv<.<>v><.<^^>^<^^<^>><>^<.vv<<<>^^v^><><^<^vv<<.<<v^^v^<<vv^<.v>^>v.v<^^<>>>.>^^v<^v>#
#<.>vv<.<>^<<.>.v<<><vvv^<<v>><<.>.vv^^<>vv^v..^<>>.^<>^>^^<^^^<v^>>>><><>^^.vv<<>v>^.v.^^<<^v<>.^>>^^>v>v^^^>v^>^>><v>><#
#<>v>vv<<<><<v><<v>v>>^.<vvvv<^^<^<>^<<^>>^^>^v.<vv^vv<>v^<>^^<>>^v.>.<.>>>.<<^><.<^^>^>>.><^>.^>v<^>^>v>.^^v>.v^>>>>>v>>#
#<.<<^>><<^>.v>v^^.v^>v<^<vv^>>>^.>>>^>^v<^v<v>.>^^<<<>v.^.v^v.^>.<v<<v^^^<<><>^><<<<>v^^><v^<>..>v.><^^.<<<^.>^<>>>vv><>#
#>^v.>vvv^^.^<>^><vv>^>v^<>.^.v<v>.^v<<v^^>^v><^v<>^>>v.^<^><<>^>>>><^^<v<<><<>^^><<<^vvv>><.<v>^>>v^^<^><>.<v^>>..^^v>v>#
#.<^^><<<^^^v<>^.>v>v^><v<>v^^.v^.^<<<^^<vvv^<^^v.<vvv<>v.v^<^>.<>><<><^v^v.^^<>^v^vvvv><<^^><<>vv<v^v^.^v<<<^v<<<^<v>v^>#
#.<^..v^^^>>^v^^.><v><>v^.>v^^<<><^^<.<>>v^>.<>>.^>vv>v>^v.<^^^<<^<vv>.^>^.<<<.^^>.^^^.v<<>v<.vv^^<>v>>>><>^>^^.<<^^<>><<#
#<^<^^>>^.<v>^^^>v><^><.v>>v^>vv>v.>^>^<^^^^v<<<^>.>v^<v.<v^^^^>v^..<<<<>^<<<>^<v^^>^vv^v>.<^v<><>^<<>^<>>v>><<>^>vvvv<>>#
#>>^.^^<v<<vvv^^<<vv>>^^<<>^^vv>>><v>^>v<v>v.><><^^v<<<.<vv>v<^^>><^v>^<>^<v<vv<v^>v<^.<<>^v<.^<.v.><.<^>^vvvvvv^v^^<^.<>#
#<><<^<.<^>^^^<v>.^v>>vv.vv<v..<^vv<>.^vv^.^<vv<>^vvv<v^>v.<v<v<.^>.<.v^>^>>>vv<>^>.>>^^^<<^v<^.vv>>v.v<v><<<^^^v^vvv..^>#
########################################################################################################################.#

3
main.go
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@@ -20,6 +20,7 @@ import (
"github.com/acw/advent2022/solutions/day21" "github.com/acw/advent2022/solutions/day21"
"github.com/acw/advent2022/solutions/day22" "github.com/acw/advent2022/solutions/day22"
"github.com/acw/advent2022/solutions/day23" "github.com/acw/advent2022/solutions/day23"
"github.com/acw/advent2022/solutions/day24"
"github.com/acw/advent2022/solutions/day3" "github.com/acw/advent2022/solutions/day3"
"github.com/acw/advent2022/solutions/day4" "github.com/acw/advent2022/solutions/day4"
"github.com/acw/advent2022/solutions/day5" "github.com/acw/advent2022/solutions/day5"
@@ -82,6 +83,8 @@ func main() {
day22.Run(os.Args[2]) day22.Run(os.Args[2])
case "day23": case "day23":
day23.Run(os.Args[2]) day23.Run(os.Args[2])
case "day24":
day24.Run(os.Args[2])
default: default:
fmt.Println("PANIC! Unknown day.") fmt.Println("PANIC! Unknown day.")
} }

313
solutions/day24/day24.go Normal file
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package day24
import (
"bufio"
"fmt"
"os"
)
type Direction int
const (
Up Direction = iota
Down
Left
Right
Stay
)
type Point struct {
x int
y int
}
type Directions []Direction
func listContains(dirs Directions, x Direction) bool {
for _, v := range dirs {
if x == v {
return true
}
}
return false
}
func sameBoard(board1 map[Point]Directions, board2 map[Point]Directions) bool {
if len(board1) != len(board2) {
return false
}
for point, vals1 := range board1 {
vals2 := board2[point]
if len(vals1) != len(vals2) {
return false
}
for _, v := range vals1 {
if !listContains(vals2, v) {
return false
}
}
}
return true
}
type Map struct {
minute int
width int
height int
elf Point
entrance Point
target Point
}
var boardStates []map[Point]Directions
func printState(state Map) {
board := boardStates[state.minute%len(boardStates)]
for y := 0; y < state.height; y++ {
for x := 0; x < state.width; x++ {
if x == state.elf.x && y == state.elf.y {
fmt.Printf("E")
} else if x == state.target.x && y == state.target.y {
fmt.Printf(".")
} else if x == state.entrance.x && y == state.entrance.y {
fmt.Printf(".")
} else if y == 0 {
fmt.Printf("#")
} else if y == state.height-1 {
fmt.Printf("#")
} else if x == 0 || x == state.width-1 {
fmt.Printf("#")
} else {
dir, exists := board[Point{x, y}]
if exists && len(dir) == 1 {
switch dir[0] {
case Left:
fmt.Printf("<")
case Right:
fmt.Printf(">")
case Up:
fmt.Printf("^")
case Down:
fmt.Printf("v")
default:
fmt.Printf("?")
}
} else if exists {
fmt.Printf("%d", len(dir))
} else {
fmt.Printf(".")
}
}
}
fmt.Println()
}
}
func okMove(state Map) bool {
if state.elf.x == state.target.x && state.elf.y == state.target.y {
return true
}
if state.elf.x <= 0 || state.elf.y <= 0 {
return false
}
if state.elf.x == state.width-1 || state.elf.y == state.height-1 {
return false
}
board := boardStates[state.minute%len(boardStates)]
_, exists := board[Point{state.elf.x, state.elf.y}]
return !exists
}
func nextBoard(width int, height int, board map[Point]Directions) map[Point]Directions {
newBoard := map[Point]Directions{}
// start with the snow move
for point, dirs := range board {
for _, dir := range dirs {
switch dir {
case Left:
newX := point.x - 1
if newX == 0 {
newX = width - 2
}
newPoint := Point{newX, point.y}
newBoard[newPoint] = append(newBoard[newPoint], Left)
case Right:
newX := point.x + 1
if newX == width-1 {
newX = 1
}
newPoint := Point{newX, point.y}
newBoard[newPoint] = append(newBoard[newPoint], Right)
case Up:
newY := point.y - 1
if newY == 0 {
newY = height - 2
}
newPoint := Point{point.x, newY}
newBoard[newPoint] = append(newBoard[newPoint], Up)
case Down:
newY := point.y + 1
if newY == height-1 {
newY = 1
}
newPoint := Point{point.x, newY}
newBoard[newPoint] = append(newBoard[newPoint], Down)
}
}
}
return newBoard
}
func nextStates(state Map) []Map {
retval := []Map{}
newMinute := state.minute + 1
stay := Map{newMinute, state.width, state.height, state.elf, state.entrance, state.target}
if okMove(stay) {
retval = append(retval, stay)
}
left := Map{newMinute, state.width, state.height, Point{state.elf.x - 1, state.elf.y}, state.entrance, state.target}
if okMove(left) {
retval = append(retval, left)
}
right := Map{newMinute, state.width, state.height, Point{state.elf.x + 1, state.elf.y}, state.entrance, state.target}
if okMove(right) {
retval = append(retval, right)
}
up := Map{newMinute, state.width, state.height, Point{state.elf.x, state.elf.y - 1}, state.entrance, state.target}
if okMove(up) {
retval = append(retval, up)
}
down := Map{newMinute, state.width, state.height, Point{state.elf.x, state.elf.y + 1}, state.entrance, state.target}
if okMove(down) {
retval = append(retval, down)
}
return retval
}
func search(initialState Map) int {
queue := []Map{initialState}
minute := -1
for len(queue) > 0 {
workState := queue[0]
if workState.minute > minute {
minute = workState.minute
filteredStates := []Map{}
pointsFound := map[Point]bool{}
for _, state := range queue {
if state.minute != minute {
fmt.Println("PANIC: WEIRD")
}
_, exists := pointsFound[state.elf]
if !exists {
filteredStates = append(filteredStates, state)
pointsFound[state.elf] = true
}
}
queue = filteredStates
continue
}
if workState.elf.x == workState.target.x && workState.elf.y == workState.target.y {
return workState.minute
}
queue = append(queue[1:], nextStates(workState)...)
}
return -1
}
func Run(filename string) {
file, err := os.Open(filename)
if err != nil {
fmt.Println("Error opening file:", err)
return
}
scanner := bufio.NewScanner(file)
scanner.Split(bufio.ScanLines)
var entrance, exit Point
board := map[Point]Directions{}
width := 0
y := 0
for scanner.Scan() {
line := []rune(scanner.Text())
if line[3] == '#' {
for x, r := range line {
if r == '.' {
if y == 0 {
entrance = Point{x, 0}
} else {
exit = Point{x, y}
}
}
}
} else {
for x, r := range line {
switch r {
case '>':
board[Point{x, y}] = Directions{Right}
case '<':
board[Point{x, y}] = Directions{Left}
case '^':
board[Point{x, y}] = Directions{Up}
case 'v':
board[Point{x, y}] = Directions{Down}
case '.', '#':
continue
default:
fmt.Println("PANIC: Unexpected character", string(r))
}
}
}
if width == 0 {
width = len(line)
}
y += 1
}
file.Close()
boardStates = []map[Point]Directions{board}
for {
nextBoard := nextBoard(width, y, boardStates[len(boardStates)-1])
if sameBoard(nextBoard, boardStates[0]) {
break
}
boardStates = append(boardStates, nextBoard)
}
fmt.Println("Pre-computed", len(boardStates), "boards.")
initialState := Map{0, width, y, entrance, entrance, exit}
printState(initialState)
foundExit := search(initialState)
fmt.Println("Found exit after", foundExit, "minutes")
backToEntrance := search(Map{foundExit, initialState.width, initialState.height, initialState.target, initialState.entrance, initialState.entrance})
fmt.Println("Made it back to the exit at", backToEntrance, "minutes")
backToExit := search(Map{backToEntrance, initialState.width, initialState.height, initialState.elf, initialState.entrance, initialState.target})
fmt.Println("And then back to the exit at", backToExit, "minutes")
}