Every Christmas in my family, each of us gives a present to only one other person. To organize who should offer a gift to whom (I call it the chain of presents), we introduced a few rules:
- There should be a single chain where every person in the family is present,
- Couples should not give to one another,
- Every person should give a gift to a different person than they had in previous years
So the problem would be to find and list the longest list of chains of presents. ...