xjk:降智题。orz
\[\begin{align} \sum_{i=1}^{n}\sum_{j=1}^{n}\sum_{k=1}^{n}(x_i \ \operatorname{and}\ x_j)\times(x_j\ \operatorname{or}\ x_k) &= \sum_{i=1}^{n}\sum_{j=1}^{n}(x_i \ \operatorname{and}\ x_j)\times\sum_{k=1}^{n}(x_j\ \operatorname{or}\ x_k) \\ &= \sum_{j=1}^{n}(\sum_{i=1}^{n}x_i \ \operatorname{and}\ x_j)\times(\sum_{k=1}^{n}x_j\ \operatorname{or}\ x_k) \\ \end{align} \]对于\(x_i\)按位求和，复杂度\(O(n)\)
标签：versus,sum,times,align,CF1466E,Apollo,operatorname,Pan From： https://www.cnblogs.com/fox-konata/p/17723287.html