sclass ManyCirclePainter {
  int w, int h;
  new L<Circle> circles;
  int[] pixels;

  L<Circle>[] startCircle, stopCircle;
  
  srecord Circle(Pt center, int radius) {}

  run {
    pixels = new int[w*h];
    if (pixels.length == 0) ret;
    
    startCircle = new L[h];
    stopCircle = new L[h];
    for (circle : circles) {
      int y1 = max(0, circle.center.y-radius);
      int y2 = circle.center.y+radius+1;
      if (y1 >= y2) continue;
      startCircle[y1] = addOrCreate(startCircle[y1], circle);
      if (y2 < h)
        stopCircle[y2] = addOrCreate(stopCircle[y2], circle);
    }
    
    for y to h: {
    }
  }
}