Toronto Code Retreat Jan 16, 2014

Secret Santa

Part 1: Assign people to a "Secret Santa" gift giving:

• Nobody must be assigned to themself;
• Everybody must give a gift to someone;
• Everybody must receive a gift from someone.

Part 2: Support additional constraints:

• Spouses can't be assigned to each other;
• If Alice gave to Bob last year, don't assign Bob to her again this year.
• Don't have Alice giving to Bob and Bob giving to Alice.

This C solution constructs a graph of people and who they can give to. The solver automatically removes everyone from their own set of possible givers, and also randomly generates a set of spousal pairings to make the problem more interesting. It recursively backtracks through possible pairings, keeping track of whether each person has been assigned as a giver, a receiver, or both.

Usage: ./santa alice bob charlie dave eddie freddie