📅  最后修改于: 2022-03-11 14:58:58.480000             🧑  作者: Mango
This problem is a special case of the b-matching problem, and hence can be solved in polynomial time. Extensive information on b-matchings can be found for instance in the book:
László Lovász and Michael D. Plummer:
Matching Theory
ISBN-10: 0-8218-4759-7
ISBN-13: 978-0-8218-4759-6