object SquaresWithOne1Rule extends SlitherlinkRule {
      def isMatch(x:Int, y:Int, req:Char): Boolean = {
        return req == '1' && x > 0 && (x - 1) < width && y > 0 && (y - 1) < height
      }

      def apply (x:Int, y:Int, req:Char): Unit = {
        if (hasWall(x - 1, y, Direction.North) && blacklist.contains((x - 1, y - 1, Direction.East))) {
          blacklist = blacklist :+ (x, y, Direction.South)
          blacklist = blacklist :+ (x, y, Direction.East)
        }
        if (hasWall(x + 1, y, Direction.North) && blacklist.contains((x + 1, y - 1, Direction.West))) {
          blacklist = blacklist :+ (x, y, Direction.South)
          blacklist = blacklist :+ (x, y, Direction.West)
        }
        if (hasWall(x - 1, y, Direction.South) && blacklist.contains((x - 1, y + 1, Direction.East))) {
          blacklist = blacklist :+ (x, y, Direction.North)
          blacklist = blacklist :+ (x, y, Direction.West)
        }
        if (hasWall(x + 1, y, Direction.South) && blacklist.contains((x + 1, y - 1, Direction.West))) {
          blacklist = blacklist :+ (x, y, Direction.North)
          blacklist = blacklist :+ (x, y, Direction.East)
        }
      }

      def unapply (x:Int, y:Int, req:Char): Unit = {
        blacklist = blacklist.filter(_ != (x, y, Direction.East))
        blacklist = blacklist.filter(_ != (x, y, Direction.West))
        blacklist = blacklist.filter(_ != (x, y, Direction.South))
        blacklist = blacklist.filter(_ != (x, y, Direction.North))
      }
    }

    object SquaresWithOne2Rule extends SlitherlinkRule {
      def isMatch(x:Int, y:Int, req:Char): Boolean = {
        return req == '1' && x > 0 && (x - 1) < width && y > 0 && (y - 1) < height
      }

      def apply (x:Int, y:Int, req:Char): Unit = {
        if (hasWall(x - 1, y, Direction.North) && blacklist.contains((x, y, Direction.East)) && blacklist.contains((x, y, Direction.South))) {
          blacklist = blacklist :+ (x - 1, y - 1, Direction.East)
        }
        if (hasWall(x + 1, y, Direction.North) && blacklist.contains((x, y, Direction.West)) && blacklist.contains((x, y, Direction.South))) {
          blacklist = blacklist :+ (x + 1, y - 1, Direction.West)
        }
        if (hasWall(x - 1, y, Direction.South) && blacklist.contains((x, y, Direction.East)) && blacklist.contains((x, y, Direction.North))) {
          blacklist = blacklist :+ (x - 1, y + 1, Direction.East)
        }
        if (hasWall(x + 1, y, Direction.South) && blacklist.contains((x, y, Direction.West)) && blacklist.contains((x, y, Direction.North))) {
          blacklist = blacklist :+ (x + 1, y + 1, Direction.West)
        }
      }

      def unapply (x:Int, y:Int, req:Char): Unit = {
        blacklist = blacklist.filter(_ != (x - 1, y - 1, Direction.East))
        blacklist = blacklist.filter(_ != (x + 1, y - 1, Direction.West))
        blacklist = blacklist.filter(_ != (x - 1, y + 1, Direction.East))
        blacklist = blacklist.filter(_ != (x + 1, y + 1, Direction.West))
      }
    }