func (this *CentriodPriorityQueue) compare(centroid1 types.Centroid, centroid2 types.Centroid) int {
	count1 := centroid1.GetCount()
	count2 := centroid2.GetCount()
	if count1 > count2 {
		return 1
	} else if count1 < count2 {
		return -1
	}
	return 0
}