Reference count

Weighted reference counting

In weighted reference counting, each reference is assigned a weight, and each object tracks not the number of references referring to it, but the total weight of the references referring to it. The initial reference to a newly created object has a large weight, such as 2. Whenever this reference is copied, half of the weight goes to the new reference, and half of the weight stays with the old reference. Since the total weight does not change, the object's reference count does not need to be updated.