按位或考点:min - max 容斥 , FWT, FMT这一题一看就知道是Min-Max容斥,下面讲一下如何求$E(minS)$$$E(minS) = \frac{1}{\Sigma_{T \cap S \not= \phi}P_T}$$$$= \frac{1}{1 - \Sigma_{T \c