code: @Override
  	int compare(Treap treap, int left, int node) {
  		// Compares two segments on a sweep line passing through m_sweep_y,
  		// m_sweep_x.
  		if (m_b_intersection_detected)
  			return -1;
  
  		int right = treap.getElement(node);
  		m_current_node = node;
  		return compareSegments(left, left, right, right);
  	}
docs: intersection at the same time.