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package langtonsant | |
import scala.annotation.tailrec | |
import scala.collection.immutable.Map | |
object Ants extends App { | |
val columnNb = 80 | |
val rowNb = 80 | |
val grid = Array.fill(rowNb * columnNb)(0) | |
loop(State(grid, c2dtoc1d(25, 25), "n")) | |
def flip(grid: Seq[Int], index: Int): Seq[Int] = { | |
val state = grid(index) | |
grid.updated(index, if (state == 0) 1 else 0) | |
} | |
def step(oldState: State): State = { | |
render(oldState.grid) | |
// println(oldState) | |
val newDirection = if (oldState.grid(oldState.position) == 1) turnRight(oldState.direction) | |
else turnLeft(oldState.direction) | |
val newPosition = move(oldState.position, newDirection) | |
State(flip(oldState.grid, oldState.position), newPosition, newDirection) | |
} | |
@tailrec | |
def loop(state: State): State = { | |
loop(step(state)) | |
} | |
def render(grid: Seq[Int]) { | |
println(grid.sliding(rowNb, columnNb).map(_.map(x => if (x == 0) "." else "#").mkString(" ")).mkString("\n")) | |
println | |
} | |
def c1dtoc2d(index: Int): Position = { | |
Position((index % columnNb), (index / columnNb)) | |
} | |
def c2dtoc1d(x: Int, y: Int) = { | |
x + (y * columnNb) | |
} | |
def move(position: Int, direction: String): Int = { | |
val pos = c1dtoc2d(position) | |
direction match { | |
case "w" => c2dtoc1d((pos.x - 1) % rowNb, pos.y) | |
case "e" => c2dtoc1d((pos.x + 1) % rowNb, pos.y) | |
case "n" => c2dtoc1d(pos.x, (pos.y - 1) % columnNb) | |
case "s" => c2dtoc1d(pos.x, (pos.y + 1) % columnNb) | |
} | |
} | |
def turnLeft = Map("w" -> "s", "s" -> "e", "e" -> "n", "n" -> "w") | |
def turnRight = Map("w" -> "n", "s" -> "w", "e" -> "s", "n" -> "e") | |
case class State(grid: Seq[Int], position: Int, direction: String) | |
case class Position(x: Int, y: Int) | |
} |
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