Bandit Problem
https://gist.github.com/syhw/a51cd8e45f0fed2b49f0
http://nbviewer.jupyter.org/github/CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers/blob/master/Chapter6_Priorities/Chapter6.ipynb
>bandit
,
UCB