class Node
  @@nodes = []
  attr_accessor :x, :y
  attr_accessor :id, :label
  def initialize(id, x, y)
    @id = id
    @x = x
    @y = y
    @@nodes.push self
  end
  def self.find_nodes(x, y, r)
    @@nodes.clone.reject { |n| (x-n.x)**2 + (y-n.y)**2 > r**2 }  # Do i really need the clone() here?
  end
  def get_neighbors(r)
    self.class.find_nodes(@x, @y, r) - [self]
  end
end