Submission #2482667

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Source Code Expand

object Main extends App {
  val Array(n, k) = io.StdIn.readLine().split(' ').map(_.toInt)
  val k2 = k*2  
  // 0 ≦ x,y ≦ 2K に圧縮
  val squares = Array.fill(k2)(Array.fill(k2)(0))
  for (i <- 1 to n) {
    val Array(x, y, color) = io.StdIn.readLine().split(' ')
    // 'W'はY方向にKずらした'B'と同値
    squares(x.toInt % k2)((y.toInt + (if (color == "B") 0 else k)) % k2) += 1
  }
  // 計算量削減のために累積和を事前算出
  for {
    i <- 0 until k2
    j <- 1 until k2
  } squares(i)(j) += squares(i)(j-1)
  for {
    j <- 0 until k2
    i <- 1 until k2
  } squares(i)(j) += squares(i-1)(j)
  var max = 0
  val end = k2-1
  for {
    i <- 0 until k
    j <- 0 until k
  } {
    // ex) k = 2
    //      ■ □ □ ■ 
    //  j+k □ ■ ■ □
    //      □ ■ ■ □
    //    j ■ □ □ ■
    //      i   i+k
    val cnt =
      (squares(i)(j)) +
      (squares(end)(j) - squares(i+k)(j)) +
      (squares(i+k)(j+k) - squares(i+k)(j) - squares(i)(j+k) + squares(i)(j)) +
      (squares(i)(end) - squares(i)(j+k)) +
      (squares(end)(end) - squares(end)(j+k) - squares(i+k)(end) + squares(i+k)(j+k))
    max = Math.max(Math.max(cnt, n - cnt), max)
  }
  print(max)
}

Submission Info

Judge Result