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QOJ

Time Limit: 1 s Memory Limit: 512 MB Total points: 100

#7792. Tree Topological Order Counting

Statistics

给定一颗 $ n $ 个点的有根树,$ 1 $ 是根,记 $ u $ 的父亲是 $ fa_u $。另给出一长度为 $ n $ 的权值序列 $ b $。

称一个长度为 $ n $ 的排列 $ a $ 为这颗树的合法拓扑序,当且仅当 $ \forall 2 \le u \le n,a_u > a_{fa_u} $。

对每个点 $ u $,定义 $ f(u) $ 为,在所有这颗树的合法拓扑序中,$ b_{a_u} $ 之和。

现在对 $ 1 \le u \le n $,求 $ f(u) \bmod 10^9+7 $。

输入格式

第一行一个整数 $ n $ 表示树的点数。

第二行 $ n-1 $ 个整数,第 $ i $ 个表示 $ fa_{i+1} $,描述树的结构。

第三行 $ n $ 个整数,第 $ i $ 个表示 $ b_i $,描述权值序列。

输出格式

一行 $ n $ 个整数,第 $ i $ 个表示 $ f(i) \bmod 10^9+7 $。

样例

样例输入 1

5
1 1 3 2 
3 5 4 4 1 

样例输出 1

18 27 27 15 15 

样例输入 2

5
1 1 3 1
1 2 3 4 5

样例输出 2

12 42 32 52 42

数据范围

Subtask$ n \le $特殊限制分值
$ 1 $$ 10 $$ 5 $
$ 2 $$ 20 $$ 10 $
$ 3 $$ 100 $$ 15 $
$ 4 $$ 350 $$ 15 $
$ 5 $$ 3000 $A$ 15 $
$ 6 $$ 3000 $$ 20 $
$ 7 $$ 5000 $$ 20 $

特殊限制 A:$ \forall 1 \le i \le n,b_i=i $。

对于所有数据:$ 2 \le n \le 5000 $,$ 1 \le fa_i < i $,$ 0 \le b_i < 10^9+7 $。

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