题目网址: http://www.puzzleup.com/2019/
http://www.puzzleup.com/2019/puzzle/?08
答题时限: 09月12日７ＰＭ－比赛结束
加分时限: 09月12日７ＰＭ－09月18日６：５９ＰＭ
答对可得基本分１００分。答案可上传５次，每改１次答案从基本分扣２０分。
比赛期间内可随时上传答案，加分时限内答对第ｎ天加（６－ｎ）分
另依题目的难易有额外加分（如有８０％的人这题答错，答对者加８０分）
◆SIT AND STAND
In a meeting there are 32 participants around a round table, some are
sitting, and some are standing. Every hour there will be a new session.
In each session participants will behave according to the following rule:
-The participants whose neighbors in the previous session being in the
same state will sit, and the participants whose neighbors being in the
opposite state will stand up.
What is the minimum number of sessions needed to guarantee that everyone
will be sitting at the table?
If the problem was asked for 4 people, the answer would be 3.
Example: If the positions are A,A,A,B in the first session, it will be
B,A,B,A in the second session, and A,A,A,A in the third session.
(A: sitting, B: standing)
在一场聚会中，有32位参与者围绕着一个圆桌，或站或坐。每个小时会进行新的活
动。每次活动参与者将依据以下规则行事：
- 参与者的左右邻居如果在上个活动同为站起或同为坐下，则参与者将会在新活动
坐下；而如果左右邻居当时是一站一坐的话，则参与者将在新活动站起来。
问至少要第几次活动，才能保证每个人都是坐下的？
如果问题是问四个人的话，答案会是3次活动。
例：如果首动是A,A,A,B,将第二动会是B,A,B,A,第三动为A,A,A,A。(A:坐着，B:站着)