Submission #423541

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Source Code Expand

import scala.collection.mutable
import scala.annotation.tailrec
import collection.JavaConversions._

object Main {

  private[this] val Array(h,w,_*) = readLine.split(" ").map(_.toInt)
  private[this] val grid = (for(i <- 0 until h) yield readLine).toArray

  type Cell = (Int,Int)

  def next(now: Cell, used: mutable.Set[Cell]): List[Cell] = {
    List((0,-1), (1,0), (0,1), (-1,0))
    .flatMap{case (dx:Int, dy:Int) => List((now._1 + dx, now._2 + dy))}
    .filter((d:Cell) => 0 <= d._1 && 0 <= d._2 && d._1 < w && d._2 < h)
    .filter((d:Cell) => grid(d._2)(d._1)!='#' && !used.contains(d))
  }

  @tailrec
  def dfs(stk: mutable.Stack[Cell], used: mutable.Set[Cell] = mutable.Set.empty[Cell]): Boolean = {

    val now = stk.pop

    if(grid(now._2)(now._1)=='g') true
    else {
      val nx = next(now,used)
      if(stk.size + nx.size == 0) false
      else dfs(stk.pushAll(nx), used + now)
    }
  }

  def main (args: Array[String]): Unit = {
    val res = for{
      sy <- 0 until h
      sx <- 0 until w
      if(grid(sy)(sx)=='s')
    } yield dfs(mutable.Stack((sx,sy)))

    println(if(res.fold(false)(_ | _))"Yes" else "No")
  }
}

Submission Info

Compile Error

warning: there were two deprecation warnings; re-run with -deprecation for details
one warning found

Judge Result