import java.awt.*;
import java.util.*;

class Circle {
  Point center; 
  Color color; 
  int radius; 
  Foam foam; 
  Circle(Foam foam) {
    this( new Point( (int) (300 * Math.random()), 0), 
          new Color( (float) Math.random(), (float) Math.random(), (float) Math.random()), 
          10 + (int) (60 * Math.random()), 
          foam
        ); 
  }
  Circle(Point center, Color color, int radius, Foam foam) {
    this.center = center;
    this.color = color; 
    this.radius = radius;
    this.foam = foam; 
  }
  ArrayList<Circle> neighbors = new ArrayList<Circle>(); 
  boolean fall() {
    if (this.neighbors.size() == 0 && this.center.y <= 560 - this.radius) {
      this.center.y += 5;  
      for (Circle c : foam) {
        if (this != c && c.overlaps(this)) {
          this.neighbors.add(c); 
          c.neighbors.add(this);  
        }
      }
      return true;
    } else {
      return false;  
    }
  }
  void draw(Graphics g) {
    g.setColor(this.color); 
    g.fillOval(this.center.x - this.radius, 
               this.center.y - this.radius, 
               2 * this.radius, 
               2 * this.radius);
    g.setColor(Color.BLACK); 
    g.drawOval(this.center.x - this.radius, 
               this.center.y - this.radius, 
               2 * this.radius, 
               2 * this.radius);
    
  }
  boolean overlaps(Circle other) {
    return this.center.distanceTo(other.center) <= this.radius + other.radius; 
  }
}