sigongzi

摘要： 题解 一道非常神仙的计数题 如果只有一个点，就是非常简单的树型dp $f_{u} = (siz_{u} 1)! \prod_{v \in son_{u}} \frac{f_{v}}{siz_{v}!}$ $\frac{f_{u}}{siz_{u}!} = \frac{1}{siz_{u}} \pro 阅读全文