实现全局状态的快照算法，并监控下列程序：两个进程P和Q用两个通道连成一个环，它们不断地轮转消息m。在任何一个时刻，系统中仅有一份m的拷贝。每个进程的状态是指由它接收到m的次数。P首先发送m。在某一点，P得到消息且它的状态是101。在发送m之后，P启动快照算法，要求记录由快照算法报告的全局状态。(The snapshot algorithm of global state is implemented, and the following programs are monitored: two processes P and Q are connected into a ring by two channels, and they continuously rotate the message M. At any time, there is only one copy of m in the system. The state of each process is the number of times it receives M. P sends m first. At some point, P gets the message and its status is 101. After M is sent, P starts the snapshot algorithm, and records the global status reported by the snapshot algorithm.)