Who Buys The Croissants?
July 30, 2013
There was a big buzz on Stack Overflow recently when a question about buying croissants was asked:
At my office someone buys croissants for everybody every Friday. Sometimes we have problems arranging a suitable schedule because of absences — illness, vacation, training, customer meetings — so we’re looking for an algorithm that randomly chooses the person who should bring croissants so that everyone buys and consumes about as many croissants as everyone else.
The question caused a big ruckus at Stack Overflow, and is currently locked while the community decides if the question is appropriate; I personally think that it is, and further, that the question is both fun and practical.
Your task is to devise a suitable algorithm for deciding who should buy croissants, and demonstrate by simulation that your algorithms is fair. When you are finished, you are welcome to read or run a suggested solution, or to post your own solution or discuss the exercise in the comments below.
Programming Praxis 
so it sounds like your just looking for a uniform rng.
here’s one that outputs a random schedule.
http://pastebin.com/yUV1kEDT