排列组合问题 6人围成一桌
问题描述：
排列组合问题 6人围成一桌
How many ways are there to seat six people around a circular table where seatings are considered to be the same if they can be obtained from each other by rotating the table
答
The answer is (6-1)!=120
If there are n people,then the answer is (n-1)!