How to make check points in a message passing system?

如何在一个消息传递系统进行检查？

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System to facilitate the selection of students and check points.

系统方便了学生选课和查分。

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While paying tickets, they must provide their personal payment information. They might also check points for their offense in a catalog.

在支付票费时，他们必须提供他们私人的支付信息。

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a I'm not, so come down here check palindrome that the two end points a and a are the same and call this again also.

判断两端都是,然后再次调用,注意发生了什么。

麻省理工公开课 - 计算机科学及编程导论课程节选

There's the base case. If it's longer than one, what do I want to do? Well I'd like to check the two end points to see are they the same character? And if they are, then oh, I just need to know is everything else in the middle a palindrome?

如果只有一个元素也是回文，这是基本事件,如果比一个长的话那么我应该怎么做？,我将会查看两头是否相同？,如果是的,我只要知道中间剩下的部分是不是回文即可？

麻省理工公开课 - 计算机科学及编程导论课程节选

The police set up vehicle check points, and detectives went door to door in the vicinity looking for witnesses but were baffled that no one had reported the apparent victims missing.

WSJ: 'Abduction' Was a Prank, Police Find

Nigerians are increasingly questioning the police and military response, one that relies more on labor-intensive check points rather than intelligence operations that could provide tips on weapons or the composition of the group.

WSJ: Attacks in Nigeria Kill at Least 143

Most of these are caravans and prefabs, some smuggled in piecemeal past the army's check-points.

ECONOMIST: Israel