Crazy tea party，这是一个数论中排列组合的问题，问题是围在一个圆桌坐着的多个人如何能在最短时间内完成座位的对换-Crazy tea party, this is a permutation and combination of number theory, the problem is sitting around a round table on how much individuals can in the shortest time to complete the seat

解决大数阶乘最后非零位的问题。涉及数论知识。-Solve the problem of large number factorial at last nonzero. It requires Knowledge of number theory.