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Today’s puzzle is a new twist on a classic genre: the “common knowledge” hat riddle in which logicians deduce facts about their hats based on what they know, and what they know others know.
，更多细节参见51吃瓜
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Data centers need huge crews during construction—and far fewer workers once they’re up and running. There will be maintenance, retrofits, and expansions, but not at the same scale as the initial build-outs. For workers, that can mean moving on when a project wraps, or facing periods without a job lined up. During the 2008 recession, for example, nearly one in four of IBEW’s construction members were out of work.